I treat the spoons and ladles I carve with food grade organic flax/linseed oil and roast in a fan oven at 180 deg C, giving a robust coating that is also very safe. A few coats are required to fill all the pores in the wood for a beautiful satin finish but all the coats can be completed in a couple of hours total. Colours start at a something slightly darker than the natural oil colour and darken to the colour of chocolate depending on how long they’re in the oven for. The smell is of hot cooking oil unless you go for full chocolate brown in which case it starts to smell of burnt oil and a bit smoky. Fully dry your item first and heat it up slowly in the oven to 180 deg C before applying the first coat so that all areas cure and colour equally. Saturate the wood initially then wipe off all excess with a paper towel which you can then use to add the subsequent coats. Check on the spoon and remove any drips that appear during roasting before they harden. Silicone oven mitts are great for handling the spoons while hot.
Author here, I also bought a dehydrator to keep my finished spoons at 70C (158F) for 10 hours to speed up the curing of the tung oil. It really works wonders!
I prefer to keep the original color of the wood I sell, so lower temperatures are better for me, but I like the look of toasted wood as well.
My problem with just oil is that the finish is very matte, hence the wax and resin complication I'm going through in the article. But matte is also a look that people look for so there's no problem in that, it's just my personal preference and style that's different.
Do those oils polymerize at that temperature and are those polymers food safe? Also how stable are they since spatulas routinely come into contact with high temperatures?
I honestly do not know because while I have read that specifically boiled linseed oil does cure to be safe it was not clear to me whether it was safe for skin contact or fully food safe and food safe isn’t the same thing as safe for e.g. stirring pasta as it boils or stirring food that is frying in oil.
Boiled linseed oil is because the additives make it look like boiling - this contradicts the article but I believe the article is wrong. One of the traditional additives was lead, but even the modern lead free versions are not all that safe for food unless the manufacture claims otherwise (most don't)
You can still get actual "proper" double boiled linseed oil. It's not even especially expensive, just mildly annoying to source. It's a surprisingly durable finish for outdoor furniture etc, just takes an age to cure compared to the chemically boiled linseed oil.
Could you deep fry the spoons in your oil of choice? Imagine a commercial fry cook from a fast food restaurant. The heat would open the wood pores there by removing moisture content replaced with penetrant from the oil bath. Remove, let cool, and wipe off. In theory I don't believe there's anything wrong with the idea.
Deep frying works well when the oil is held well above water's boiling point, keeping excessive amounts of oil from soaking in because steam escaping from the food keeps excessive oil from entering. That doesn't work with wood.
Just a heads up, rags used with raw linseed oil will ignite if you aren't careful with them. People say that only the rags used with boiled linseed oil will start fires, but I've seen rags used with raw oil ignite on two occasions.
Also...most linseed coatings will mold if they're not kept dry. If you'd like to avoid that, look for purified linseed oil -- it's regular linseed oil, but the proteins that mold feeds on have been removed. If you really want to go crazy, look for the stuff made from food grade oil.
Absolutely, very good of you to add. The idea of using a drying/boiled linseed oil did not occur to me till now, and the idea is equal parts funny and scary to entertain. Would a wood utensil soaked with wet drying oil even survive the toasting process without turning the oven - and my shop - into an impromptu fireplace? If it did make it, would the heavy metals and charred surface oils add off-flavors to my stew?
Some recommend non-edible petrol-based mineral oil (aka liquid parrafin) because it doesn’t go rancid, but has the same effect of not actually doing much for protection and will leak into hot liquids.
Why even use wood if you’re going to cover it in a layer of clear plastic?
I find it amusing that those who will use wood or "natural" (petroleum is also naturally occurring...) products for some sort of weird misguided eco-virtue-signaling, inevitably end up needing to basically reinvent the chemistry of finding an inert, durable material that brought us modern plastics. All these drying oils create a layer of polymerised material, which can be classed as plastic anyway. Waxes, regardless of source, attribute their properties to long hydrocarbon chains, just like polyethylene.
Author here, I was mostly referring to the practice of coating the wood in a layer of smooth plastic that makes the wood not feel and look like wood anymore. It's like something that you want to keep encased forever.
I'm of the same opinion as you, drying oil polymers are still plastic, it's just that their method of curing makes them look better on wood, most likely because of the very thin layer that remains at the surface, but also because of the polymer surface texture.
Every epoxy resin, even the more penetrant ones, end up looking like plastic on wood, not sure how else to describe it.
But in terms of chemistry, food safety and how inert they are, they are indistinguishable.
I'm also aware mineral oil is food safe, I was trying to say that it will leak into the hot food and not stay in the wood fibers, which renders the finish useless after just one use.
I really enjoyed your article. In regard to the parent comment: it’s also enough to say “I enjoy this and this is how I want to spend my time”. So what if it’s reinventing the wheel - the act of learning and crafting itself can be immensely satisfying regardless of the end result.
I came at your article from a slightly different perspective. Rubio monocoat is quite expensive, especially if you’re trying to run a business selling products coated in it. You’re probably already aware, but I think base Rubio is essentially oil + carnauba + a small amount of paraffin. I make large pieces of furniture, and finishing with Rubio can go through multiple cans! So making my own finish has become a priority. That’s not even accounting for Blacktail Studio coating too.
There is a large difference between extracting fossil fuels from the ground and using substances extracted from plants. Only one of them is renewable, and hence the only sustainable way for the human species to live.
Yes but it is important not to confuse the source with the form.
For example we can create hydrocarbons using solar/wind energy and that is still "renewable" even though hydrocarbons are involved. They are merely the medium of energy storage.
Call me when the hydrocarbons we buy off the shelf are actually made from wind and solar. Until that day you’re still arguing for the artificiality of a real distinction.
How much are you willing to pay? https://renewablelube.com/ mostly plant based for the solar source. In general about 5x the price of pumped oil, and they may not last as long. I've bought for them before, no other relation
Prices of products are a very strong function of total production. Solar panel electricity once was 20x the price of other ways - now its 0.5x or less. In competitive industries the price will come down to only a small multiplier on raw input price.
Technologies of making synthetic fuel using energy, water and carbon dioxide are a century old and they have been used for producing great quantities is special circumstances when the price did not matter, e.g. by Germany during WWII (though at that time they produced cabon monoxide by burning coal, instead of reducing carbon dioxide from air, because this was cheaper).
The only reason why they are not used now is that the current price of fossil oil is significantly lower.
There is research to develop more efficient methods for the synthesis of hydrocarbons, based on the electrolytic reduction of carbon dioxide, but their progress is slow, in good part because such critical research is funded much less than frivolous research, such as that for AGI.
marine plankton and algae in the Mesozoic & Cenozoic eras mostly. Hardly considered renewable unless you plan to cover the earth in large warm shallow seas with the right tectonic conditions to deposit dead marine life instead of allowing it to rapidly decompose
I have used a 50/50 blend of food-safe mineral oil and beeswax with good success on my little hobby projects (and as a regular treatment for my cutting board) but admittedly I'm not making ladles you'd dip into boiling soup, so I paid less attention to the extreme temperature issue
well, it's an arts and crafts project and they may value avoiding petrochemical products in the end-product. regardless it's interesting to work through that whole process instead of just accepting it.
My biggest grief with wooden utensils replaceing plastic ones and cardboard(-ish) cup lids replacing plastic lids is the texture - I almost shudder everytime these environmentally friendly replacements touch my mouth, to the point that I eat in the most ridiculous way in order to avoid having to touch the wooden fork when I'm trying to get the food off of it.
And the reason is exactly the finish. Metal and plastic spoons, forks, lids, etc. are nice and smooth and don't get in your way. Cheaply made wood or cardboards ones are rough and tacky.
Of course you could argue that from an environmental standpoint, that's not a bug but a feature: now I'm using even less disposable stuff (first, no plastic because it's been replaced by other stuff; and second also the replacements because I hate using them).
Try bamboo chopsticks. They are smooth because they are made parallel to the grain. There is minimal end grain surface area, so you rarely have to interact with the rough bits. And they do almost everything you'd want a consumer-oriented utensil to do.
This is the hardest thing about selling wooden spoons and especially cups. Like you, most people think about the rough texture they felt when using cheap or disposable wooden utensils.
My spoons and cups feel more like warm textured ceramic. They are sanded to a high 600 grit, water popped multiple times to make sure the grain doesn't raise and the texture stays smooth, and finished with drying oils as you see in the article to keep the surface highly hydrophobic.
I really can't describe it in words, but everyone I know who tried eating with my wooden spoons and drank from my coffee cups, was pleasantly surprised of the feeling.
That's why most of my sales happen in person at local craft markets, because there, people can take the cup into their hand, they can feel the smoothness, and they can ask about the same things you are worried about.
All I can recommend is find a spoon carver in your area, or one that ships there, and try a hand carved eating spoon. I'm not saying it's better than metal, ceramic or plastic, it's just a different experience that some people enjoy.
My partial solution is to look a bit silly and shove the utensil in my mouth while I walk around setting up the meal (finding a seat, opening the package etc). Wetting the eating surface with your saliva for ~30-60 seconds helps a lot.
Yeah people fuss over wooden spoons way too much. My wooden spoons cost me $1-2 each at Walmart, and I abuse the hell out of them knowing that if I ever need to replace them, I have more than got my money's worth.
>You can use soap if you want, but studies have shown it doesn’t make a difference.
(...no links provided). Really? "Studies show" you don't need to use soap to rinse off the wooden cutting board you just chopped up raw chicken on? Without a citation there I'm extremely skeptical
Not sure where you read that, but the person is obviously wrong (EDIT: oh I see, they say it in the otherwise very good article linked in GP). Soap helps reduce pathogens just like does in washing hands: it doesn't sterilize, but it removes a huge amount, and makes it so subsequent proper sterilization (bleach, heat, etc) properly reaches the surface.
But, yes, if you just soap a board and rinse after cutting raw chicken on it, and then immediately (i.e. without allowing drying overnight) put on e.g. raw vegetables, and then e.g. throw those raw veggies in the fridge to be consumed / eaten hours or days later, then indeed the simple washing may not in general be enough, or may not be practically much different than using lots of very hot running water. E.g. some epidemiological studies fail to find washing habits predict outbreaks (https://academic.oup.com/jaoac/article-abstract/89/2/538/565...).
But the conclusion to draw from this is not to skip the soap, but, rather, that the drying is often a more crucial part of good washing than the particular washing method.
> The current scientific consensus as far as I can see is that wooden is less safe than plastic or glass as it results in more biofilm formation, and more absorption than plastic or glass.
Actually, the myth is still that plastic is safer. That "debunking" you linked is extremely biased and poor, uses very dated and selective sources, and at least one of the papers it cites is irrelevant nonsense (testing for contamination from raw chicken without even washing the boards: https://doi.org/10.1111/j.1472-765X.2011.03039.x) and the conclusion is broadly contradicted by numerous modern reviews (see [1-3] below) and other papers, including ones that look at actual epidemiological data and find no difference or more safety from wooden boards [2]. Biofilm also generally takes days or 24 hours minimum to form, and requires constant moisture, so claims that any kind of cutting board develop "more biofilm" are immediately suspect as well, and clearly do not reflect any kind of sane real-world usage.
It is trivial to search Google Scholar for this topic and see that, in most cases, there are no meaningful practical differences for bacterial safety between wood vs. plastic boards, and, if anything, the anti-microbial properties and self-healing nature of wood boards probably in general do make them safer than plastic boards, which quickly get permanent gouges that harbor more bacteria.
Wood cutting boards can also be rapidly sterilized in a microwave, which is more convenient for cooking dishes with multiple ingredients than e.g. the dishwasher for plastic boards, or dilute bleach, for either. And in fact the whole argument is moot precisely because the real clear factor is obviously proper washing and sterilizing. Given the astounding lack of evidence for plastic superiority, and the clear evidence that cutting boards produce non-trivial micro-plastics [4], it is still quite reasonable to prefer wood overall, at least in the home.
References:
[1] Aviat, F., Gerhards, C., Rodriguez-Jerez, J.-j., Michel, V., Bayon, I.L., Ismail, R. and Federighi, M. (2016), Microbial Safety of Wood in Contact with Food: A Review. COMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, 15: 491-505. https://doi.org/10.1111/1541-4337.12199
[2] Dean O Cliver, Cutting Boards in Salmonella Cross-Contamination, Journal of AOAC INTERNATIONAL, Volume 89, Issue 2, 1 March 2006, Pages 538–542, https://doi.org/10.1093/jaoac/89.2.538
[3] Boursillon D, Riethmüller V (2007), "The safety of wooden cutting boards: Remobilization of bacteria from pine, beech, and polyethylene". British Food Journal, Vol. 109 No. 4 pp. 315–322, doi: https://doi.org/10.1108/00070700710736561
[4] Özuluğ, O., Şarlak, İ., Sarcan, F., … Yürekli, Ö. D. (2025). Health Risks and Environmental Threats of the Food Prepared on Plastic Cutting Boards. Turkish Journal of Bioscience and Collections, 9(2), 65-75. https://doi.org/10.26650/tjbc.1745221
Oh and actually, the stackexchange debunking is just full of even more flat out nonsense. His link to the USDA actually also says there is no reason to prefer plastic to wood, and his link to the "Canadian Institute of Food Safety" literally advises people against dilute bleach, and tells people to "wipe [wooden cutting boards] down with a solution of vinegar and water". Dilute vinegar doesn't kill anything, and bleach is universally recommended, so this should tell you something about the stackexchange poster's complete and total inability to judge research and the reputability of sources.
All the reasons he gives for wooden boards being worse are literally directly opposite to the truth (plastic gouges more easily because wood self-heals; the absorbent properties of wood is actually a plus that promotes drying and kills bacteria). It is shocking how horribly uninformed that post is.
Okay, probably no one cares, but I wanted to look into this "biofilm" claim, because it is quite incredible but makes no real sense, but on the surface, seems to be from a legitimate paper that is reasonably well-cited. Looking into it, I would say it is clear the stackexchange poster definitely doesn't know what they are talking about, and seriously misrepresents the study [1], which is quite terrible.
As a first bad sign, though this paper is published in 2018, the authors fail to cite any of the numerous prior studies showing no differences or superior behavior of wood relative to plastic, indicating some pretty glaring biases right at the outset. Moving on:
> "Formation and quantification of biofilm. To verify if all 10 strains were biofilm producers, we used plastic, wood, and glass circles with a diameter of 1 cm. These materials were washed, dried, and autoclaved in a Petri dish. Next, with sterilized tweezers, each circle was placed on the bottom of a well in a 24-well plate. Plastic and wood circles were obtained by cutting samples from commercially sold boards. [...] The Salmonella strains were incubated in Luria-Bertani (LB) broth at 35°C/24 h. Next, the culture was diluted [...]. Aliquots of 300 lL were distributed in triplicate into the wells, and the plates were incubated at 35°C/96h."
Obviously no cutting board is ever in such conditions, and even still, their Table 1 shows in fact that there is NO significant difference (4 plastic vs 6 wood) in samples in biofilm growth. At no point do they ever show meaningful growth of biofilm on a washed cutting board allowed to dry.
They also don't mention if these are new cutting boards, which invalidates the whole thing, since the problem is that plastic cutting boards gouge and then don't wash properly. Every decent study looks at used or gouged boards as well, otherwise they don't reflect real-world usage.
> "Each Salmonella strain was incubated in BHI broth at 35°C/24 h and diluted [...], and 1 mL was uniformly spread on a chicken breast surface, previously thawed, and Salmonella-free. Next, each [cutting board] surface was contaminated by rubbing with the contaminated chicken for 30s. This step was performed in duplicate to assure the transfer of Salmonella from the cutting surface to the cucumber because a cotton swab would capture most cells on the first rub (item a, below mentioned), leading to an undetectable count in the vegetable due to the low number of residual cells (item b, below mentioned)"
You can judge if this is realistic or not. Also, if a simple swab is removing so much cells that they couldn't detect anything in the vegetables later, how could washing not possibly be removing the same? This is an extremely suspicious comment in general. Let's see:
> "the contaminated boards were washed before they were exposed to the cucumber. The washing was performed with hot running water for 10s, vigorously scrubbed with a new sponge moistened with neutral liquid detergent, rinsed in hot running water, and dried"
Surely not, but it sounds like they are washing with a dry sponge moistened only with detergent? Dried for how long? Because we already know it needs to be hours in all cases, this is nothing new. Was the sponge abrasive or a soft one? You need an abrasive and lots of hot water, not a dry, soft sponge "moistened" only with pure detergent, and ten seconds of scrubbing if you want washing to do anything at all, especially smeared chicken breast. Smeared chicken always needs a two-phase wash, once with a harsh abrasive tool (scouring pad or brush) with soap, then a rinse, and then again with a normal sponge, or you obviously have chicken bits left behind. Nothing about the procedure sounds adequate.
> "As expected, when the surfaces were unwashed after contact with the contaminated poultry, all strains were recovered. Regarding the washed surfaces, the wooden one showed the highest positivity in recovery of pathogens, occurring in 9 out of 10 tested strains. Fewer positive samples were observed on plastic and glass surfaces, 3 of 10 and 1 of 10, respectively. According to the Cochran test, both surfaces differed significantly from wood, showing them to be the easier materials to be sanitized, in the absence of biofilm ( p < 0.05)."
The inexact and high p-value means this is exceedingly weak evidence (actually not significant if you account for multiple comparisons), and what is a "positive sample" in terms of actual counts is not defined, which is also highly suspect. Also why are we using such a weird statistical test? Real studies will have log reductions or actual counts (e.g. [3] - which also looks to find plastic to be worse, from what I can read). Very p-hacky.
"All samples of cucumbers displayed the presence of Salmonella Enteritidis, regardless of the cutting surface material unwashed [sic]. After washing, the wooden cutting surface showed the highest transfer of bacterial cells to cucumber, followed by plastic and glass surfaces, which again were shown to be the more hygienic materials, differing statistically from wood. On the contrary, all cucumber samples were contaminated with Salmonella Enteritidis, even after washing the cutting surface in the presence of biofilm [emphasis mine]"
So in one case (salmonella without biofilm) wood looks worse with marginal significance, but in all cases where the salmonella is biofilm-producing, it doesn't matter what the board is made of. Pretty unconvincing.
So, yeah, nope. Use plastic or wood, just clean properly.
[1] Dantas, S. T., Rossi, B. F., Bonsaglia, E. C., Castilho, I. G., Hernandes, R. T., Fernandes, A., & Rall, V. L. (2018). Cross-contamination and biofilm formation by Salmonella enterica serovar Enteritidis on various cutting boards. Foodborne Pathogens and Disease, 15(2), 81-85. https://scholar.google.ca/scholar?output=instlink&q=info:H9T...
[2] Bischoff, A., Alter, T., & Schoenknecht, A. (2025). Hygienic Evaluation of Wooden Cutting Boards: Microbiological Parameters. Journal of food protection, 88(9), 100576. https://doi.org/10.1016/j.jfp.2025.100576
[3] Pegueros-Valencia, C. A., Lucero-Mejía, J. E., Hernández-Iturriaga, M., & Godínez-Oviedo, A. (2025). Assessing Salmonella enterica biofilm formation in frequent scenarios of chicken handling in domestic kitchen environments. Food microbiology, 132, 104849. https://doi.org/10.1016/j.fm.2025.104849
Sure, but the article is mainly about looks (and in the case of wood cups, which seem fairly impractical, although sake cups are ok unfinished, taste transfer). They can look nicer with a finish. I generally dont care, I keep my salad spoons with some oil, and my cooking spoons plain.
Woodworker and person who has spent a tremendous amount of time on wood finishing chemistry here.
This is very confused.
First, all wood finishes you can buy are food-safe once cured. They aren't allowed to be sold otherwise, at least in the US/Europe/et al.
If you are using them once heated, this is not always as true (and regulations vary a bit), but if we are talking about food prep/salad/you name it, they are all safe.
Heat wise, if we are talking about using it in boiling water to stir something, most finishes would be fine from a safety standpoint (not all can withstand this though).
As a general rule of thumb, if you aren't heating the wood above 200F, you aren't really going to get a finishes to release toxic fumes[1]
Second, as for solvents - smell is not everything. The HDI he mentions rubio having will not smell like anything until the concentration is way way way way too high. If you can smell it, you are in trouble. HDI is also much more dangerous than most solvents[2].
The oil is also a solvent.
Solvents are just things that you can dissolve something else in.
If they want to avoid certain types of solvents for some reason, that should be about safety or something, and if they want to evaluate that, smell is probably the wrong evaluation criteria.
To give one example of solvent elimination with a purpose, let's take VOC's, which are about pollution[3].
Avoiding VOC solvents makes for cleaner air, but again, VOC compliant/exempt/etc solvents vary wildly in whether they are safer for people or not than non-VOC exempt solvents.
If you are trying instead to avoid human-toxic solvents, you would choose a different set, etc.
[1] There are so many finishes with so many different properties that i can't 100% guarantee this, but non-professional stuff you can buy at a woodworking store or a big box store is going to be fine
[2] The lack of smell of isocyanate's is main the reason you can get service life indicating respirator catridges from 3m/et al - otherwise you would not be able to determine if your cartridge is working or not, since you would not smell it when spray finishing/etc until the concentration is way too high, even if your cartridge is spent. Sane folks just use supplied air anyway, rather than risk it at all.
[3] not safety to humans, though often highly confused with being safer.
I expect most would count baking and candy making among "food prep." the latter of which routinely reaches temperatures around 200-300°F. If stirring a mixture of boiling sugar for 20 minutes at 230°F exceeds the expected food-safety threshold, it seems like there shouldn't be as casual a usage of terms as this:
> If you are using them once heated, this is not always as true (and regulations vary a bit), but if we are talking about food prep/salad/you name it, they are all safe.
Also, spatula hits the pan quite often and the pan surface routinely goes way above 200F. Talking searing and it's what 400F to 500F? Boiling too, the pan surface gets much hotter than boiling water.
I've been using Osmo oils. This top oil and also their butcher block. Besides what they say that it is food safe, would this be fine for utensils which may get exposure to cooking temperatures ? Whether mixing soup or stir fry ?
Osmo topoil is actually mostly what it says on the can - wax + oil. The wax part will melt/degrade very quickly at cooking temps. the oil portion will not.
If you are exposing it to cooking temps, and want something very natural, i'd just use an oil and not a "hardwax". The wax part is not going to buy anything.
"hardwax" is just a made up term that means nothing for real, some of them are harder waxes (carnauba), some of them are not.
In any case, none of them will survive heat, because the wax won't.
Honestly I just use the utensils unfinished. They work fine and survive dishwashing fine. I still have over 20 years old cooking spoons that go through this kind of abuse.
They deliberately label the not food safe ones as "not food safe" and "not a wood finish". They have to.
So if you are using that as a wood finish, you get what you get?
Also most of it is still food safe when cured anyway, it just does't always fully cure and it's hard to tell when it's cured.
But once the polymerization/etc has actually finished, there are no oxidizing agents or driers or ... left.
If you look at the law suits that lead to it being labeled the way it is, it's not about food safe when cured, it's about the inability to tell when curing actually finished, and final curing taking a very long time.
- most finishes are indeed "food safe after curing", I'm aware of that. How they look on wood, how they perform when being dipped in hot soup or when drinking hot liquids from them, that's harder to assess without buying cans of finish that I have to store forever if I don't like them.
- HDI doesn't smell indeed, I never said it did. In fact two-component hardwax oils would have been perfect if it was easier to mix and apply in small quantities. Unfortunately for the few drops of oil I need on a spoon, it's too messy
- I'm talking about solvents in the definition that most consumers know about them: volatile solvents that usually smell strongly. I used low-VOC solvent-based finishes and they still smell. Organic components aren't the only smelly things in solvents, and I simply can't stand them anymore, that's all. It's not all about the dangers, it's for my own comfort.
If you can point me to a solvent-based hardwax oil that smells of only the oils and waxes inside, I'll buy it in a pinch and forget about melting waxes in my microwave. Google search doesn't help here, I need to hear it from someone with experience
"Sane folks just use supplied air anyway, rather than risk it at all."
For small one-time projects it's generally fine to just use a brand new filter and toss it afterwards. Hobbyists painting a car panel aren't using supplied air.
People often put the cartridges in a plastic (or sometimes mylar if they are advanced) bag to save money, and change them when they can smell stuff. This is a bad plan with isocyanate.
Auto finishes are moving towards iso-free 2k urethanes anyway.
(wood will get there, but tends to lag)
PU is about the last coating I'd like to see on my food utensils. Not very interested in a daily dose of microplastics injected directly into my food...
Depends wildly on the finish. For boiling, i just wouldn't worry.
Most of the toxic fumes/etc come from breaking molecular bonds. There is a minimum temperature, and below that temperature, it just doesn't really occur.
If it starts happening, regardless of whether there is visible smoke/vapor, the finish will quite obviously visibly degrade. Either it will flake off, slough off, or you will just be able to remove it with your fingernail.
Take polyurethanes - they mostly start releasing toxic fumes at 300-400F just about the second they get to that temperature.
Below that, nothing.
This is because that's the temperature at which the isocyanate bonds start to break, even if there is no flame. You will not see smoke or vapor. But it will become essentially non-protective and flake off or otherwise visibly degrade.
At a much higher temperature (700-800F) you would break down the polyol, which point it will likely flat out ignite, and burn with a very thick, toxic smoke. People used to actually think polyurethane foam was non-flammable. It's highly flammable. It just has a high ignition temperature. In houses, you are now required to cover it with some form of fire barrier or otherwise meet E-84 criteria through additives, etc.
We don't worry too much about this for wood pieces, because the only time they are exposed to this level of heat is when something is already on fire :)
Also keep in mind that things that are called polyurethanes may or may not actually be polyurethanes.
There is the "colloquial" name that you often find for a finish in marketing literature, and then the actual chemistrsy.
A good example is water-based lacquers, which are usually just acrylic resins.
Most polyurethanes are actually polyurethanes of some sort. Everything else is often a wacky mix.
> Some carvers use urushi lacquer which is the sap from a tree common to Japan.
Urushi is the name of the Japanese tree, Toxicodendron verniciflua (the genus formerly was named Rhus), and of the lacquer of which its sap is the main constituent.
The lacquer is also called urushiol (note, not urushoil), which is also the resinous substance found in other members of the Toxicodendron genus: T. radicans and T. rydbergii, or poison ivy; T. diversilobum and T. pubescens, poison oak; and T. vernix, poison sumac. The resinous oil is what causes allergic reactions.
Which finally gets to my point: What are the allergic affects of the tree, its raw sap, the liquid lacquer, and maybe for hypersenstive/reactive urushiol allergies, the finished lacquer?
I don't meant to be alarmist - people have been eating off urushi lacquer for centuries. I'm thinking more about working with it.
EDIT: For those interested in the scientific aspects of the resin, plants, and allergic reaction:
Aaron C. Gladman MD. Toxicodendron Dermatitis: Poison Ivy, Oak, and Sumac. Wilderness & Environmental Medicine vol 17 #2 (June 2006)
> Which finally gets to my point: What are the allergic affects of the tree, its raw sap, the liquid lacquer, and maybe for hypersenstive/reactive urushiol allergies, the finished lacquer?
The Wood Database can be a useful practical site for this sort of thing. I found [0], a page for a different wood which is said to contain the same allergen:
> The sap contains urushiol (the same allergen found in Poison Ivy), and can still be irritating to some sensitized individuals even after the wood has been dried, and sap can also seep through some wood finishes to the surface of the wood.
Same as poison ivy? Count me out if true: I react badly.
> What are the allergic affects of the tree, its raw sap, the liquid lacquer, and maybe for hypersenstive/reactive urushiol allergies, the finished lacquer?
Essentially the same as for any other urushiol.
I'm highly sensitive and had to ask my partner not to get into kintsugi with the traditional lacquers because even the tiniest spot of urushiol and I will be considering a trip to the burn unit.
I've gotten a very mild reaction from ~century old lacquerware but I wouldn't expect that to be common, once it's fully cured. And just because it's mild doesn't mean it's any less itchy, trust me.
> What are the allergic affects of the tree, its raw sap, the liquid lacquer, and maybe for hypersenstive/reactive urushiol allergies, the finished lacquer?
Answering my own question, based on reading my own source more carefully (Gladman 2006 p.122):
The Japanese urushi tree, T. verniciflua, is among "plants containing uroshiol cross-reacting chemicals", which are described as follows (note that genus Toxicodendron is in family Anacardiaceae):
"Similar compounds found in other members of the Anacardiaceae family, as well as in several non-Anacardiaceae plants, can lead to cross-reactions and to an identical clinical picture (Table 2). However, dermatitis induced by these cross-reactors is rare compared with the frequency of dermatitis from Toxicodendron species. The allergens in the non-Toxicodendron plants listed in Table 2 are generally noncatechol phenols and resorcinols, and not the highly allergenic catechols in poison ivy, oak, and sumac. The hypothesis that early skin exposure to catechols may allow cross-reaction to other Anacardiaceae, whereas early oral exposure to phenols and resorcinols may induce tolerance, has been expressed."
Regarding the chemical composition, urushiol (in poison ivy/oak/sumac): "is a mixture of 3-n-pentadecylcatechols, which contain a catechol ring moiety substituted with different aliphatic side chains at position 3 or 4."
Some people react very badly, some are immune. But to be honest I just don't like my spoons and cups to look lacquered and I don't prefer the process of application.
Nothing wrong with that though, I like reading and watching people do the process and seeing them enjoy the calmness in doing dozens of layers over multiple days. Some end up with very beautiful shimmery brown wooden pieces [0] and I would love to own some of them. It's just not my style.
If you're interested in Urushi, here's an account from an artist who went to Japan to learn how to work with it - https://garlandmag.com/lacquer-god/
"Essentially a concentrated form of poison ivy, uncured lacquer causes blistering rashes which cause its sufferer almost unbearable itch and many sleepless nights. Building tolerance typically takes up to two years and has students living in constant fear of the very material they eventually hope to use on a daily basis."
Ouch. Rereading my source above (Gladman 2006), they say hyposensitization (desensitization, if I understand correctly) generally doesn't work, but ...
"Lasting natural hyposensitization has been reported, however, among Japanese woodworkers who use lacquer derived from Toxicodendron verniciflua, the Japanese lacquer tree. In a 1991 survey, 81% of craftsmen developed dermatitis from the lacquer but 83% of these reactions resolved with continued exposure."
As a child, my grandmother once accidentally used a poison oak stem to roast a hotdog over a campfire. She hadn't cooked it hot enough to denature the oil, and she reacted to it internally, which required a hospital visit.
Granted, consuming it is the worst-case scenario, but exposure to those oils can be life threatening.
> There’s also Rubio Monocoat and other two-component hardwax oils where the base component is usually a solvent-free blend of drying oils and waxes, and the accelerator component is Hexamethylene diisocyanate or HDI. The base component can cure on its own in about 3 weeks and the accelerator shortens the curing time to less than a day.
I find it bizarre that these finishes market the HDI component as an “accelerator”. It seems quite clearly to be a crosslinking agent — it’s a longish molecule with a rather reactive isocyanate group at either end. If you mix it with things it can react with, which likely includes both some waxes (those with hydroxyl groups) and some of the modified oils in “hardwax” oil, it will turn them into something akin to polyurethane.
Rubio Monocoat will cure into a different substance with the “accelerator” added than without it. In either case, it cures quite slowly and IMO has a nasty, penetrating chemical smell for weeks. I like how it looks, but the finish is not as stain resistant as many other options are, with or without the HDI.
P.S. the SDSes and some common sense suggest that this stuff is actually HDI oligomers, not plain HDI. The oligomers are rather less nasty.
P.P.S. Isocyanates are, AIUI, not persistently nasty, as they are too reactive. They react with water to form amines, and unreacted isocyanates will react with the amines to form polyurea, which is reasonably inert.
P.P.P.S. The “molecular bonding” stuff that Rubio talks about seems to be nonsense. The part A + part B mix will cure into a fairly hard and tough plasticky substance even if it’s a millimeter or two thick. Don’t do that — it’s not so easy to get the resulting mess off of whatever surface it cured on!
Author here! Since the article publishing, I have found a widely available finish that's very similar to what I'm doing called Walrus Oil Furniture Butter: https://walrusoil.com/products/furniture-butter
It's still a combination of polymerizing oils, hard waxes and resin, it's just different plants (linseed instead of tung, pine resin instead of damar etc.) Again, no solvents, people say it smells good.
I still have way too much tung oil, wax and resin around because I could only buy high quantities, so I guess I'll keep using my own finish for a long while. But I'd love to hear from others how the Furniture Butter fares for wooden spoons and cups.
This is an interesting article, though I wish they had relaxed some of the requirements. Demanding something that both cures fast and is free of solvents seems unnecessarily specific. For hobby projects finishing on a tight deadline is usually not a high priority so longer cure times are an acceptable tradeoff. For larger scale or business oriented projects the use of a solvent can be fine because proper VOC protective gear is not that expensive.
Even for hobby work it’s not hard to get reasonable VOC protective gear or establish a fume extraction hood out of some cardboard and a cheap box fan next to a window in the shop space.
The author of the article has a woodworking business (linked on the bottom of their homepage: https://gospodaria.com/). So they do need fast turnaround times for profitability.
However, as they mention, they do this work from home, and they don't really have a good setup for VOC protection. From the article:
> In the winter months I carve indoors and have to finish the pieces indoors as well, and the horrible solvent smell fills my house for a whole day.
A jury-rigged fume hood will work if you're doing one item at a time, but it doesn't work if you're doing work in batches.
(I get the impression that the best next step for the author, would be to consider building themselves a humidity-controlled drying shed, which would live at least a few feet from their building's air envelope. Doesn't need to be anything fancy; build an ordinary shed, and then get the small-space HVAC equipment from e.g. a marijuana grow-tent supplier.)
I always wondered whether the wooden spatulas and spoons they sell at IKEA are safe to use. I never know what that wood was treated with or coated with.
Perhaps I’m naive, but buying from an IKEA (in Norway) or another big store feels less risky than buying something handmade.
Several people are involved in making every product at IKEA. At least one of them must be an expert in compliance. They can expect scrutiny and product recalls, fines and bad sales if they’re found out.
The one person making the hand-made spoon does not necessarily know all the environmental regulations that should be followed.
I had a ceramic coffee mug that I loved and used very regularly. I bought it at a fair from a local potter and it had a very unique glaze, lots of blues and greens.
A friend who is a potter saw me drinking out of it and said that the glaze looked suspicious. He said it looked loaded with heavy metals, and that I should probably not use it or at least get it tested.
At the time I knew a guy who worked in a lab that tested certain substances for hazardous materials. He was intrigued and brought it in to work one day, and later texted me asking if I wanted it back, because it was very likely leaching cobalt, lead, and cadmium, and it was probably also very mildly radioactive.
I feel much better drinking out of mugs from IKEA and other big name stores.
They are raw wood, unfinished. I usually give them a little sanding and a layer of beeswax - doesn't last very long but makes them feel new for a while :)
Well unless you are getting solid wood utensils (much more $$ and most aren’t) then you are starting with bamboo glued together with adhesives. So at that point if you are worried about the finish I’d be worried about the glues as well
I get solid wood (olive wood or other woods ) tools and I don’t finish them. But if I did I might just use beeswax
Cooking utensils are mostly one piece, otherwise wood glue is PVA, same as school glue, that's about as non-toxic as you can get. I'd be more concerned about some kind of supply-chain issue contaminating the raw wood - hopefully they do frequent control checks on the material.
These are strips glued together aka laminated. The binder is not PVA (which is water soluble and not suitable for the task), it’s most commonly a formaldehyde resin such as phenol- , urea- or melamine urea formaldehyde
That’s plain bambu, the dark areas are the nodes/rings in the plant.
I don’t build cutting boards myself, but have never heard of using anything but food-safe PVA glue. Those resins are used for laminating plywood etc, probably not even legal to use in kitchen utensils, at least in the EU.
That is a terrible assumption to make. Regular lacquer for example does poorly under temperatures commonly encountered when preparing food and it’s basically a mix of solvents.
The solvents evaporate when the lacquer cures, right? A lacquered spatula or spoon could leach some plasticizers when heated up. But who on earth would go to the trouble of spray lacquering a spatula? It doesn't seem like a real concern. Wooden spoons from IKEA aren't gonna poison you!
Flexner's "Understanding Wood Finishing" has a section about "the myth of food safety" that pretty directly states that food safety isn't a serious concern for fully cured finishes.
I use wood only for my non-stick pans. Metal for the metal pans. I sometime put some olive oil on the utensils, but generally, I just use them, put them in the dishwasher, repeat, until they break. They are ~50 cents at Ikea. And so I don't eat any plastics anymore.
Of course, the article is about high end stuff, but I just want to put everything in the dishwasher. Which I presume you can't do with even the best coated high end utensils?
We also switched to wooden Cutting boards, I find them to be pretty annoying as they really go bad fast in the dishwasher and can be quite expensive. We just wash them with boiling water, a bit of soap every now and then.
Seems a little extreme to pour boiling water on wooden cutting boards to clean? Do you live in really cold and snowy place without much access to sunlight hours? Just washing them with soap and drying them in sunlight is all we do and it’s been good. We also don’t cut meat on the wooden board. I would use hot water if it were meat on the board.
Great blog post. I like the emd look of the experimental finish.
Couple of years back I went to all wooden spoons in the kitchen. My all time favourite is the most traditional of all: boxwood. This is what wooden utensils are made in my home country for centuries. It's light but dense, hard, and durable. It doesn't absorb color or smells easily as other hardwood. Beautiful too!
What does that mean? It's tough enough that you can make it thinner? It dries out more fully? Or does "dense" refer to something other than density, like tightness of the grain?
It's indeed the tightness of the grain, but also volumetric density (975 kg/m³) is higher than oak or spruce. What I mean with light is, indeed you can make very thin utensils and they won't break, bemd etc so at the end the product is lighter than the obe made with a softer/less dense wood.
Boxwood was for centuries the choice of wind instrument makers because of its stability and hardness, which made it possible to create thinner more practical instruments (clarinets, flute etc). till humans discovered granadillo wood, which is as dense as boxwood but much more humidity and temperature stable.
If you use the appropriate wood, you can wet and sand many times to get a smooth finish. You can burnish it (rub with hard metal) to close the surface well. But it will still stain and absorb smells, just to a lessor extent. You'll notice if you use the same spoon for coffee and tea, or the same spoon for curry and miso soup.
Why would you use a wooden spoon for those? I use wooden utensils for frying and stirring in metal pots and pans. Everything else is just the usual stainless steel type suitable for utensils.
I don't have a problem. if they get a little funky I just sand them down. and let them soak in food-grade mineral oil for a while. same with cutting boards and butcher block tables.
When the wood fibers get wet they swell and become soft. When soft, the surface will be very sensitive to damage. Fibers on the surface will raise and then not return to their original position, causing surface roughness. Repeated cycles of wet/dry will cause cracks.
Alin (OP), what a wonderful article. I've had the same problem and had given up experimenting for similar reasons to you. I'm now thinking to finish the cup I've half carved and have sitting on the shelf in the shed. Thanks!
Your shop looks great too. Others might enjoy folowing the link buried towards the bottom of the article.
Thank you for the kind words! Do try to finish your cup, it's a great experience both to drink from something made by your hands, and to drink from a wooden cup if it's finished well.
Make sure you do water popping after finishing the carving and sanding process. It's what makes the difference between wood that catches your lips and wood that feels like ceramic. The process is simple: sand with 600 or 400 grit, whichever you have, then get all the wood wet with water (faucet is fine), let dry completely (hairdryer helps), sand again with 600/400 grit and repeat about 3 times until wetting the wood no longer makes it feel rough.
Great advice thanks, and a new technique to learn too. When making walking sticks I usually go to 1200 grit, or 2500 where finish is really important. Finishing is my favourite part of the job, similar to your point about epoxy (why would you want to interface with a layer of plastic?)
The timing of this is sort of uncanny as it's been on my mind a lot lately.
Generally I use a beeswax and mineral oil finish, sometimes this other product I can't remember the name of made from flax oil.
I've been wondering why jojoba oil doesn't get mentioned more in these discussions, either in combination with something else or on its own? It's a wax but liquid at room temperature, and seems to be stable for a long long time, long enough at least that it would probably need some refinishing before it might go bad.
The problem with jojoba oil is that it doesn't polymerize or cure. It stays wet in the fibers. Nothing bad with that on wood that doesn't contact hot food and beverages.
But if you put wood treated with non-polymerized oil in a hot soup or if you pour hot tea into a cup finished with jojoba oil, the oil will get out of the fibers and into your hot liquid, the fiber will raise and the wood will start to feel rough after a few uses and start to get stained from your food and beverage.
I make wooden cups. I use water-based polyurethane out of a spray can to waterproof the interiors. I find it a lot easier to use than epoxy in almost every aspect.
For the exterior and for cutting boards, I use a hard wax oil I make from linseed oil and beeswax. It's easy to prepare and I usually provide a small cup of it to whomever I'm gifting the cutting board.
I reuse small, glass jelly jars with screw-on metal lids, about 1/2 a cup in size. You do need to leave a layer of water on top, though, because otherwise the top layer will polymerize and leave a rubbery layer you have to remove the next time you use it.
Can't a spatula be just untreated wood? Or some very light oiling just to reduce the absorption of food. And then solve the problem by disposing of them fairly often. They make a lot of heat in the fireplace since they've absorbed so much fat...
Team tung oil here. Wooden-handled knives and wooden utensils get a light coat and left outside on a nice day. Repeat for 3-5 days and you're good for at least a year or two, depending on how you treat the items. The coating needs to be light else you get a shellac/lacquer finish. I use Walrus brand, pure tung oil.
Osmo Polyx is what I already had around from other wooden furniture projects, that's all. I try to not store too many cans of unused finishes around my house so I try to use what I already have first.
Top Oil indeed seems very similar to what I did (hardwax, drying oils, driers) but half of it is still white spirit solvent, which I'm guessing will give it the same smell as Polyx.
I finished a bunch of cutlery handles with tung oil a bunch of years ago. I easily found a bottle of it at Lee Valley Tools. It was the polymerized type, which dried pretty quickly, comparable to oil paint or varnish. The finish was prety glossy. I just used a paper towel to apply several thin coats.
Taking the advice of a pro at my local makerspace, I finished a cutting board with filtered ghee. Has been great so far without turning rancid as i thought it might
Dude already found the perfect thing, but wanted an excuse to play with random metallic driers and resins instead. Fine, but don't pretend it was necessary.
But it’s really hard to mix properly and apply on small wooden objects like spoons and cups. I almost always use too much accelerator,
Just use a precision scale. Pharmacists give me side-eye when I mention cutting my medicine. No, I do small-scale epoxy mixing!
Author here, it's not that it's not possible, it's just annoying to do. Indeed, two-component hardwax oils are close to perfect (although the resulting polymer is not ideal), but having to do the precise pouring and mixing, and trying to smear that thick blend onto the wood, hundreds and hundreds of times, is not something I want to do.
I want to enjoy the process of making the wooden utensil as much as I want to see the end result, hence my excuse to play with random metallic driers and resins.
I have only used Rubio once and didn't bother with accelerant at all. For my use case it worked out fine.
Although it's the only time I've done any sort of wood finishing so take it with a grain of salt.
Kids toys, wooden kitchen utensils etc. are to be sanded and used coating free. If you really need to close off the pores, burnish the surface.
Burnishing for spatulas for example can be done on a drill press. Just use a smooth rounded end steel bar and a low speed on the drill. You’ll have the concave part done in minutes. For the handle and convex part it’s usually easiest to burnish with a smooth steel rod and move the piece along the side. I can get my hard maple spatula burnished in under 15 minutes.
If you really want to keep the fibers from rising a lot post burnishing- water pop the wood, sand with 220, slightly dampen the wood again and then burnish.
I haven’t tried this but apparently you can automate the burnishing by using antlers/smooth stones in a rock tumbler.
Interesting, I'll have to give that a detailed read later. It might be applicable to 3D prints.
To head off the people who will jump up-and-down calling me paranoid for not considering untreated printed works food safe, and accusing me of accusing them of poisoning family & friends (in some circles the discussion can get more cantankerous than the vi/emacs thing!): you keep using printed things for food without treatment if you like, and I won't judge, but I prefer to remain paranoid because if printed items were food safe it would be a selling point and I don't see any manufacturers using food based examples in their advertising.
> To head off the people who will jump up-and-down calling me paranoid for not considering untreated printed works food safe,
I’ve been involved with consumer 3D printing for over a decade and I don’t recall ever seeing a conversation where anyone suggested 3D printer parts were default food safe. It’s one of the more common FAQs you see on 3D printing forums.
I'm happy that the down-vote-y anger here is on the correct side! (unless you are the only one who agrees and the other downs are from the “how dare you suggest I might do something wrong” mob)
I treat the spoons and ladles I carve with food grade organic flax/linseed oil and roast in a fan oven at 180 deg C, giving a robust coating that is also very safe. A few coats are required to fill all the pores in the wood for a beautiful satin finish but all the coats can be completed in a couple of hours total. Colours start at a something slightly darker than the natural oil colour and darken to the colour of chocolate depending on how long they’re in the oven for. The smell is of hot cooking oil unless you go for full chocolate brown in which case it starts to smell of burnt oil and a bit smoky. Fully dry your item first and heat it up slowly in the oven to 180 deg C before applying the first coat so that all areas cure and colour equally. Saturate the wood initially then wipe off all excess with a paper towel which you can then use to add the subsequent coats. Check on the spoon and remove any drips that appear during roasting before they harden. Silicone oven mitts are great for handling the spoons while hot.
Author here, I also bought a dehydrator to keep my finished spoons at 70C (158F) for 10 hours to speed up the curing of the tung oil. It really works wonders!
I prefer to keep the original color of the wood I sell, so lower temperatures are better for me, but I like the look of toasted wood as well.
My problem with just oil is that the finish is very matte, hence the wax and resin complication I'm going through in the article. But matte is also a look that people look for so there's no problem in that, it's just my personal preference and style that's different.
Do those oils polymerize at that temperature and are those polymers food safe? Also how stable are they since spatulas routinely come into contact with high temperatures?
I honestly do not know because while I have read that specifically boiled linseed oil does cure to be safe it was not clear to me whether it was safe for skin contact or fully food safe and food safe isn’t the same thing as safe for e.g. stirring pasta as it boils or stirring food that is frying in oil.
Boiled linseed oil is because the additives make it look like boiling - this contradicts the article but I believe the article is wrong. One of the traditional additives was lead, but even the modern lead free versions are not all that safe for food unless the manufacture claims otherwise (most don't)
You can still get actual "proper" double boiled linseed oil. It's not even especially expensive, just mildly annoying to source. It's a surprisingly durable finish for outdoor furniture etc, just takes an age to cure compared to the chemically boiled linseed oil.
Could you deep fry the spoons in your oil of choice? Imagine a commercial fry cook from a fast food restaurant. The heat would open the wood pores there by removing moisture content replaced with penetrant from the oil bath. Remove, let cool, and wipe off. In theory I don't believe there's anything wrong with the idea.
Deep frying works well when the oil is held well above water's boiling point, keeping excessive amounts of oil from soaking in because steam escaping from the food keeps excessive oil from entering. That doesn't work with wood.
That's exactly why it will work great, allowing deep oil penetration, no?
As a hobbyist woodworker, I've been wondering how to protect my projects. I need to try this, great idea, thanks for sharing.
Just a heads up, rags used with raw linseed oil will ignite if you aren't careful with them. People say that only the rags used with boiled linseed oil will start fires, but I've seen rags used with raw oil ignite on two occasions.
Also...most linseed coatings will mold if they're not kept dry. If you'd like to avoid that, look for purified linseed oil -- it's regular linseed oil, but the proteins that mold feeds on have been removed. If you really want to go crazy, look for the stuff made from food grade oil.
Just make sure it's a linseed oil without dryer's; they're usually heavy metal compounds.
Absolutely, very good of you to add. The idea of using a drying/boiled linseed oil did not occur to me till now, and the idea is equal parts funny and scary to entertain. Would a wood utensil soaked with wet drying oil even survive the toasting process without turning the oven - and my shop - into an impromptu fireplace? If it did make it, would the heavy metals and charred surface oils add off-flavors to my stew?
Some recommend non-edible petrol-based mineral oil (aka liquid parrafin) because it doesn’t go rancid, but has the same effect of not actually doing much for protection and will leak into hot liquids.
Highly-refined mineral oil is food-safe.
https://en.wikipedia.org/wiki/Mineral_oil#Food_preparation
Why even use wood if you’re going to cover it in a layer of clear plastic?
I find it amusing that those who will use wood or "natural" (petroleum is also naturally occurring...) products for some sort of weird misguided eco-virtue-signaling, inevitably end up needing to basically reinvent the chemistry of finding an inert, durable material that brought us modern plastics. All these drying oils create a layer of polymerised material, which can be classed as plastic anyway. Waxes, regardless of source, attribute their properties to long hydrocarbon chains, just like polyethylene.
Author here, I was mostly referring to the practice of coating the wood in a layer of smooth plastic that makes the wood not feel and look like wood anymore. It's like something that you want to keep encased forever.
I'm of the same opinion as you, drying oil polymers are still plastic, it's just that their method of curing makes them look better on wood, most likely because of the very thin layer that remains at the surface, but also because of the polymer surface texture.
Every epoxy resin, even the more penetrant ones, end up looking like plastic on wood, not sure how else to describe it.
But in terms of chemistry, food safety and how inert they are, they are indistinguishable.
I'm also aware mineral oil is food safe, I was trying to say that it will leak into the hot food and not stay in the wood fibers, which renders the finish useless after just one use.
I really enjoyed your article. In regard to the parent comment: it’s also enough to say “I enjoy this and this is how I want to spend my time”. So what if it’s reinventing the wheel - the act of learning and crafting itself can be immensely satisfying regardless of the end result.
I came at your article from a slightly different perspective. Rubio monocoat is quite expensive, especially if you’re trying to run a business selling products coated in it. You’re probably already aware, but I think base Rubio is essentially oil + carnauba + a small amount of paraffin. I make large pieces of furniture, and finishing with Rubio can go through multiple cans! So making my own finish has become a priority. That’s not even accounting for Blacktail Studio coating too.
There is a large difference between extracting fossil fuels from the ground and using substances extracted from plants. Only one of them is renewable, and hence the only sustainable way for the human species to live.
Yes but it is important not to confuse the source with the form.
For example we can create hydrocarbons using solar/wind energy and that is still "renewable" even though hydrocarbons are involved. They are merely the medium of energy storage.
Call me when the hydrocarbons we buy off the shelf are actually made from wind and solar. Until that day you’re still arguing for the artificiality of a real distinction.
How much are you willing to pay? https://renewablelube.com/ mostly plant based for the solar source. In general about 5x the price of pumped oil, and they may not last as long. I've bought for them before, no other relation
Prices of products are a very strong function of total production. Solar panel electricity once was 20x the price of other ways - now its 0.5x or less. In competitive industries the price will come down to only a small multiplier on raw input price.
Technologies of making synthetic fuel using energy, water and carbon dioxide are a century old and they have been used for producing great quantities is special circumstances when the price did not matter, e.g. by Germany during WWII (though at that time they produced cabon monoxide by burning coal, instead of reducing carbon dioxide from air, because this was cheaper).
The only reason why they are not used now is that the current price of fossil oil is significantly lower.
There is research to develop more efficient methods for the synthesis of hydrocarbons, based on the electrolytic reduction of carbon dioxide, but their progress is slow, in good part because such critical research is funded much less than frivolous research, such as that for AGI.
>"Only one of them is renewable, and hence the only sustainable way for the human species to live"
Irrelevant for spoon making, too few of those ;)
Guess where the fossil fuels came from...?
marine plankton and algae in the Mesozoic & Cenozoic eras mostly. Hardly considered renewable unless you plan to cover the earth in large warm shallow seas with the right tectonic conditions to deposit dead marine life instead of allowing it to rapidly decompose
From biological matter. You are made of hydrocarbons as is every other living thing on this planet.
I have used a 50/50 blend of food-safe mineral oil and beeswax with good success on my little hobby projects (and as a regular treatment for my cutting board) but admittedly I'm not making ladles you'd dip into boiling soup, so I paid less attention to the extreme temperature issue
>All these drying oils create a layer of polymerised material, which can be classed as plastic anyway.
No, that is absolutely not the case.
Do you care to say why not?
Ah yes: "Congratulations! You have just completed the cycle of recapitulating the collection of processes which have brought us the present!"
well, it's an arts and crafts project and they may value avoiding petrochemical products in the end-product. regardless it's interesting to work through that whole process instead of just accepting it.
Wood is rigid and won’t melt or scratch
100% - this sort of insanity is just silly.
My biggest grief with wooden utensils replaceing plastic ones and cardboard(-ish) cup lids replacing plastic lids is the texture - I almost shudder everytime these environmentally friendly replacements touch my mouth, to the point that I eat in the most ridiculous way in order to avoid having to touch the wooden fork when I'm trying to get the food off of it.
And the reason is exactly the finish. Metal and plastic spoons, forks, lids, etc. are nice and smooth and don't get in your way. Cheaply made wood or cardboards ones are rough and tacky.
Of course you could argue that from an environmental standpoint, that's not a bug but a feature: now I'm using even less disposable stuff (first, no plastic because it's been replaced by other stuff; and second also the replacements because I hate using them).
Try bamboo chopsticks. They are smooth because they are made parallel to the grain. There is minimal end grain surface area, so you rarely have to interact with the rough bits. And they do almost everything you'd want a consumer-oriented utensil to do.
Cooking chopsticks also replace a bunch of cookware for me.
This article is talking about high-end hand-carved kitchen utensils. Spoons you cook with, not spoons you eat with.
The article also has a whole section on a wooden coffee cup!
This is the hardest thing about selling wooden spoons and especially cups. Like you, most people think about the rough texture they felt when using cheap or disposable wooden utensils.
My spoons and cups feel more like warm textured ceramic. They are sanded to a high 600 grit, water popped multiple times to make sure the grain doesn't raise and the texture stays smooth, and finished with drying oils as you see in the article to keep the surface highly hydrophobic.
I really can't describe it in words, but everyone I know who tried eating with my wooden spoons and drank from my coffee cups, was pleasantly surprised of the feeling.
That's why most of my sales happen in person at local craft markets, because there, people can take the cup into their hand, they can feel the smoothness, and they can ask about the same things you are worried about.
All I can recommend is find a spoon carver in your area, or one that ships there, and try a hand carved eating spoon. I'm not saying it's better than metal, ceramic or plastic, it's just a different experience that some people enjoy.
My partial solution is to look a bit silly and shove the utensil in my mouth while I walk around setting up the meal (finding a seat, opening the package etc). Wetting the eating surface with your saliva for ~30-60 seconds helps a lot.
I get plastic, but what's wrong with metal utensils?
Nothing, you might have misread my comment.
[flagged]
Sir, yes sir, will do.
Later.
I'm personally on team Robinson. For wooden objects actually used with food, the best finish is no finish.
https://www.finewoodworking.com/2024/10/10/the-best-food-saf...
Yeah people fuss over wooden spoons way too much. My wooden spoons cost me $1-2 each at Walmart, and I abuse the hell out of them knowing that if I ever need to replace them, I have more than got my money's worth.
>You can use soap if you want, but studies have shown it doesn’t make a difference.
(...no links provided). Really? "Studies show" you don't need to use soap to rinse off the wooden cutting board you just chopped up raw chicken on? Without a citation there I'm extremely skeptical
I believe this is the paper they based the article on.
https://www.researchgate.net/publication/369940932_Wood_Cutt...
Not sure where you read that, but the person is obviously wrong (EDIT: oh I see, they say it in the otherwise very good article linked in GP). Soap helps reduce pathogens just like does in washing hands: it doesn't sterilize, but it removes a huge amount, and makes it so subsequent proper sterilization (bleach, heat, etc) properly reaches the surface.
But, yes, if you just soap a board and rinse after cutting raw chicken on it, and then immediately (i.e. without allowing drying overnight) put on e.g. raw vegetables, and then e.g. throw those raw veggies in the fridge to be consumed / eaten hours or days later, then indeed the simple washing may not in general be enough, or may not be practically much different than using lots of very hot running water. E.g. some epidemiological studies fail to find washing habits predict outbreaks (https://academic.oup.com/jaoac/article-abstract/89/2/538/565...).
But the conclusion to draw from this is not to skip the soap, but, rather, that the drying is often a more crucial part of good washing than the particular washing method.
You're right to be: it's a common myth. Here's a write-up debunking it, with 6 citations: https://cooking.stackexchange.com/a/130364/57154
> The current scientific consensus as far as I can see is that wooden is less safe than plastic or glass as it results in more biofilm formation, and more absorption than plastic or glass.
Actually, the myth is still that plastic is safer. That "debunking" you linked is extremely biased and poor, uses very dated and selective sources, and at least one of the papers it cites is irrelevant nonsense (testing for contamination from raw chicken without even washing the boards: https://doi.org/10.1111/j.1472-765X.2011.03039.x) and the conclusion is broadly contradicted by numerous modern reviews (see [1-3] below) and other papers, including ones that look at actual epidemiological data and find no difference or more safety from wooden boards [2]. Biofilm also generally takes days or 24 hours minimum to form, and requires constant moisture, so claims that any kind of cutting board develop "more biofilm" are immediately suspect as well, and clearly do not reflect any kind of sane real-world usage.
It is trivial to search Google Scholar for this topic and see that, in most cases, there are no meaningful practical differences for bacterial safety between wood vs. plastic boards, and, if anything, the anti-microbial properties and self-healing nature of wood boards probably in general do make them safer than plastic boards, which quickly get permanent gouges that harbor more bacteria.
Wood cutting boards can also be rapidly sterilized in a microwave, which is more convenient for cooking dishes with multiple ingredients than e.g. the dishwasher for plastic boards, or dilute bleach, for either. And in fact the whole argument is moot precisely because the real clear factor is obviously proper washing and sterilizing. Given the astounding lack of evidence for plastic superiority, and the clear evidence that cutting boards produce non-trivial micro-plastics [4], it is still quite reasonable to prefer wood overall, at least in the home.
References:
[1] Aviat, F., Gerhards, C., Rodriguez-Jerez, J.-j., Michel, V., Bayon, I.L., Ismail, R. and Federighi, M. (2016), Microbial Safety of Wood in Contact with Food: A Review. COMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, 15: 491-505. https://doi.org/10.1111/1541-4337.12199
[2] Dean O Cliver, Cutting Boards in Salmonella Cross-Contamination, Journal of AOAC INTERNATIONAL, Volume 89, Issue 2, 1 March 2006, Pages 538–542, https://doi.org/10.1093/jaoac/89.2.538
[3] Boursillon D, Riethmüller V (2007), "The safety of wooden cutting boards: Remobilization of bacteria from pine, beech, and polyethylene". British Food Journal, Vol. 109 No. 4 pp. 315–322, doi: https://doi.org/10.1108/00070700710736561
[4] Özuluğ, O., Şarlak, İ., Sarcan, F., … Yürekli, Ö. D. (2025). Health Risks and Environmental Threats of the Food Prepared on Plastic Cutting Boards. Turkish Journal of Bioscience and Collections, 9(2), 65-75. https://doi.org/10.26650/tjbc.1745221
Oh and actually, the stackexchange debunking is just full of even more flat out nonsense. His link to the USDA actually also says there is no reason to prefer plastic to wood, and his link to the "Canadian Institute of Food Safety" literally advises people against dilute bleach, and tells people to "wipe [wooden cutting boards] down with a solution of vinegar and water". Dilute vinegar doesn't kill anything, and bleach is universally recommended, so this should tell you something about the stackexchange poster's complete and total inability to judge research and the reputability of sources.
All the reasons he gives for wooden boards being worse are literally directly opposite to the truth (plastic gouges more easily because wood self-heals; the absorbent properties of wood is actually a plus that promotes drying and kills bacteria). It is shocking how horribly uninformed that post is.
Okay, probably no one cares, but I wanted to look into this "biofilm" claim, because it is quite incredible but makes no real sense, but on the surface, seems to be from a legitimate paper that is reasonably well-cited. Looking into it, I would say it is clear the stackexchange poster definitely doesn't know what they are talking about, and seriously misrepresents the study [1], which is quite terrible.
As a first bad sign, though this paper is published in 2018, the authors fail to cite any of the numerous prior studies showing no differences or superior behavior of wood relative to plastic, indicating some pretty glaring biases right at the outset. Moving on:
> "Formation and quantification of biofilm. To verify if all 10 strains were biofilm producers, we used plastic, wood, and glass circles with a diameter of 1 cm. These materials were washed, dried, and autoclaved in a Petri dish. Next, with sterilized tweezers, each circle was placed on the bottom of a well in a 24-well plate. Plastic and wood circles were obtained by cutting samples from commercially sold boards. [...] The Salmonella strains were incubated in Luria-Bertani (LB) broth at 35°C/24 h. Next, the culture was diluted [...]. Aliquots of 300 lL were distributed in triplicate into the wells, and the plates were incubated at 35°C/96h."
Obviously no cutting board is ever in such conditions, and even still, their Table 1 shows in fact that there is NO significant difference (4 plastic vs 6 wood) in samples in biofilm growth. At no point do they ever show meaningful growth of biofilm on a washed cutting board allowed to dry.
They also don't mention if these are new cutting boards, which invalidates the whole thing, since the problem is that plastic cutting boards gouge and then don't wash properly. Every decent study looks at used or gouged boards as well, otherwise they don't reflect real-world usage.
> "Each Salmonella strain was incubated in BHI broth at 35°C/24 h and diluted [...], and 1 mL was uniformly spread on a chicken breast surface, previously thawed, and Salmonella-free. Next, each [cutting board] surface was contaminated by rubbing with the contaminated chicken for 30s. This step was performed in duplicate to assure the transfer of Salmonella from the cutting surface to the cucumber because a cotton swab would capture most cells on the first rub (item a, below mentioned), leading to an undetectable count in the vegetable due to the low number of residual cells (item b, below mentioned)"
You can judge if this is realistic or not. Also, if a simple swab is removing so much cells that they couldn't detect anything in the vegetables later, how could washing not possibly be removing the same? This is an extremely suspicious comment in general. Let's see:
> "the contaminated boards were washed before they were exposed to the cucumber. The washing was performed with hot running water for 10s, vigorously scrubbed with a new sponge moistened with neutral liquid detergent, rinsed in hot running water, and dried"
Surely not, but it sounds like they are washing with a dry sponge moistened only with detergent? Dried for how long? Because we already know it needs to be hours in all cases, this is nothing new. Was the sponge abrasive or a soft one? You need an abrasive and lots of hot water, not a dry, soft sponge "moistened" only with pure detergent, and ten seconds of scrubbing if you want washing to do anything at all, especially smeared chicken breast. Smeared chicken always needs a two-phase wash, once with a harsh abrasive tool (scouring pad or brush) with soap, then a rinse, and then again with a normal sponge, or you obviously have chicken bits left behind. Nothing about the procedure sounds adequate.
> "As expected, when the surfaces were unwashed after contact with the contaminated poultry, all strains were recovered. Regarding the washed surfaces, the wooden one showed the highest positivity in recovery of pathogens, occurring in 9 out of 10 tested strains. Fewer positive samples were observed on plastic and glass surfaces, 3 of 10 and 1 of 10, respectively. According to the Cochran test, both surfaces differed significantly from wood, showing them to be the easier materials to be sanitized, in the absence of biofilm ( p < 0.05)."
The inexact and high p-value means this is exceedingly weak evidence (actually not significant if you account for multiple comparisons), and what is a "positive sample" in terms of actual counts is not defined, which is also highly suspect. Also why are we using such a weird statistical test? Real studies will have log reductions or actual counts (e.g. [3] - which also looks to find plastic to be worse, from what I can read). Very p-hacky.
"All samples of cucumbers displayed the presence of Salmonella Enteritidis, regardless of the cutting surface material unwashed [sic]. After washing, the wooden cutting surface showed the highest transfer of bacterial cells to cucumber, followed by plastic and glass surfaces, which again were shown to be the more hygienic materials, differing statistically from wood. On the contrary, all cucumber samples were contaminated with Salmonella Enteritidis, even after washing the cutting surface in the presence of biofilm [emphasis mine]"
So in one case (salmonella without biofilm) wood looks worse with marginal significance, but in all cases where the salmonella is biofilm-producing, it doesn't matter what the board is made of. Pretty unconvincing.
So, yeah, nope. Use plastic or wood, just clean properly.
[1] Dantas, S. T., Rossi, B. F., Bonsaglia, E. C., Castilho, I. G., Hernandes, R. T., Fernandes, A., & Rall, V. L. (2018). Cross-contamination and biofilm formation by Salmonella enterica serovar Enteritidis on various cutting boards. Foodborne Pathogens and Disease, 15(2), 81-85. https://scholar.google.ca/scholar?output=instlink&q=info:H9T...
[2] Bischoff, A., Alter, T., & Schoenknecht, A. (2025). Hygienic Evaluation of Wooden Cutting Boards: Microbiological Parameters. Journal of food protection, 88(9), 100576. https://doi.org/10.1016/j.jfp.2025.100576
[3] Pegueros-Valencia, C. A., Lucero-Mejía, J. E., Hernández-Iturriaga, M., & Godínez-Oviedo, A. (2025). Assessing Salmonella enterica biofilm formation in frequent scenarios of chicken handling in domestic kitchen environments. Food microbiology, 132, 104849. https://doi.org/10.1016/j.fm.2025.104849
Same. I have a wood cutting board and I always use hot water and dish soap to clean it after.
Sure, but the article is mainly about looks (and in the case of wood cups, which seem fairly impractical, although sake cups are ok unfinished, taste transfer). They can look nicer with a finish. I generally dont care, I keep my salad spoons with some oil, and my cooking spoons plain.
Woodworker and person who has spent a tremendous amount of time on wood finishing chemistry here.
This is very confused.
First, all wood finishes you can buy are food-safe once cured. They aren't allowed to be sold otherwise, at least in the US/Europe/et al.
If you are using them once heated, this is not always as true (and regulations vary a bit), but if we are talking about food prep/salad/you name it, they are all safe.
Heat wise, if we are talking about using it in boiling water to stir something, most finishes would be fine from a safety standpoint (not all can withstand this though).
As a general rule of thumb, if you aren't heating the wood above 200F, you aren't really going to get a finishes to release toxic fumes[1]
Second, as for solvents - smell is not everything. The HDI he mentions rubio having will not smell like anything until the concentration is way way way way too high. If you can smell it, you are in trouble. HDI is also much more dangerous than most solvents[2].
The oil is also a solvent.
Solvents are just things that you can dissolve something else in.
If they want to avoid certain types of solvents for some reason, that should be about safety or something, and if they want to evaluate that, smell is probably the wrong evaluation criteria.
To give one example of solvent elimination with a purpose, let's take VOC's, which are about pollution[3].
Avoiding VOC solvents makes for cleaner air, but again, VOC compliant/exempt/etc solvents vary wildly in whether they are safer for people or not than non-VOC exempt solvents.
If you are trying instead to avoid human-toxic solvents, you would choose a different set, etc.
[1] There are so many finishes with so many different properties that i can't 100% guarantee this, but non-professional stuff you can buy at a woodworking store or a big box store is going to be fine
[2] The lack of smell of isocyanate's is main the reason you can get service life indicating respirator catridges from 3m/et al - otherwise you would not be able to determine if your cartridge is working or not, since you would not smell it when spray finishing/etc until the concentration is way too high, even if your cartridge is spent. Sane folks just use supplied air anyway, rather than risk it at all.
[3] not safety to humans, though often highly confused with being safer.
I expect most would count baking and candy making among "food prep." the latter of which routinely reaches temperatures around 200-300°F. If stirring a mixture of boiling sugar for 20 minutes at 230°F exceeds the expected food-safety threshold, it seems like there shouldn't be as casual a usage of terms as this:
> If you are using them once heated, this is not always as true (and regulations vary a bit), but if we are talking about food prep/salad/you name it, they are all safe.
Also, spatula hits the pan quite often and the pan surface routinely goes way above 200F. Talking searing and it's what 400F to 500F? Boiling too, the pan surface gets much hotter than boiling water.
I've been using Osmo oils. This top oil and also their butcher block. Besides what they say that it is food safe, would this be fine for utensils which may get exposure to cooking temperatures ? Whether mixing soup or stir fry ?
https://osmo.ca/product/topoil-high-solid/
Osmo topoil is actually mostly what it says on the can - wax + oil. The wax part will melt/degrade very quickly at cooking temps. the oil portion will not.
If you are exposing it to cooking temps, and want something very natural, i'd just use an oil and not a "hardwax". The wax part is not going to buy anything.
"hardwax" is just a made up term that means nothing for real, some of them are harder waxes (carnauba), some of them are not. In any case, none of them will survive heat, because the wax won't.
Honestly I just use the utensils unfinished. They work fine and survive dishwashing fine. I still have over 20 years old cooking spoons that go through this kind of abuse.
First, all wood finishes you can buy are food-safe once cured.
Standard BLO is not food-safe and is sold everywhere.
They deliberately label the not food safe ones as "not food safe" and "not a wood finish". They have to.
So if you are using that as a wood finish, you get what you get?
Also most of it is still food safe when cured anyway, it just does't always fully cure and it's hard to tell when it's cured.
But once the polymerization/etc has actually finished, there are no oxidizing agents or driers or ... left.
If you look at the law suits that lead to it being labeled the way it is, it's not about food safe when cured, it's about the inability to tell when curing actually finished, and final curing taking a very long time.
Author here, to address some of your points:
- most finishes are indeed "food safe after curing", I'm aware of that. How they look on wood, how they perform when being dipped in hot soup or when drinking hot liquids from them, that's harder to assess without buying cans of finish that I have to store forever if I don't like them.
- HDI doesn't smell indeed, I never said it did. In fact two-component hardwax oils would have been perfect if it was easier to mix and apply in small quantities. Unfortunately for the few drops of oil I need on a spoon, it's too messy
- I'm talking about solvents in the definition that most consumers know about them: volatile solvents that usually smell strongly. I used low-VOC solvent-based finishes and they still smell. Organic components aren't the only smelly things in solvents, and I simply can't stand them anymore, that's all. It's not all about the dangers, it's for my own comfort.
If you can point me to a solvent-based hardwax oil that smells of only the oils and waxes inside, I'll buy it in a pinch and forget about melting waxes in my microwave. Google search doesn't help here, I need to hear it from someone with experience
"Sane folks just use supplied air anyway, rather than risk it at all."
For small one-time projects it's generally fine to just use a brand new filter and toss it afterwards. Hobbyists painting a car panel aren't using supplied air.
Sure, i meant if you are doing work repeatedly.
People often put the cartridges in a plastic (or sometimes mylar if they are advanced) bag to save money, and change them when they can smell stuff. This is a bad plan with isocyanate.
Auto finishes are moving towards iso-free 2k urethanes anyway. (wood will get there, but tends to lag)
PU is about the last coating I'd like to see on my food utensils. Not very interested in a daily dose of microplastics injected directly into my food...
What if you're using it as a serving spoon from a boiling dish? How much heat can it withstand (or for how long) before it's unsafe
Depends wildly on the finish. For boiling, i just wouldn't worry.
Most of the toxic fumes/etc come from breaking molecular bonds. There is a minimum temperature, and below that temperature, it just doesn't really occur.
If it starts happening, regardless of whether there is visible smoke/vapor, the finish will quite obviously visibly degrade. Either it will flake off, slough off, or you will just be able to remove it with your fingernail.
Take polyurethanes - they mostly start releasing toxic fumes at 300-400F just about the second they get to that temperature. Below that, nothing.
This is because that's the temperature at which the isocyanate bonds start to break, even if there is no flame. You will not see smoke or vapor. But it will become essentially non-protective and flake off or otherwise visibly degrade.
At a much higher temperature (700-800F) you would break down the polyol, which point it will likely flat out ignite, and burn with a very thick, toxic smoke. People used to actually think polyurethane foam was non-flammable. It's highly flammable. It just has a high ignition temperature. In houses, you are now required to cover it with some form of fire barrier or otherwise meet E-84 criteria through additives, etc.
We don't worry too much about this for wood pieces, because the only time they are exposed to this level of heat is when something is already on fire :)
Also keep in mind that things that are called polyurethanes may or may not actually be polyurethanes.
There is the "colloquial" name that you often find for a finish in marketing literature, and then the actual chemistrsy.
A good example is water-based lacquers, which are usually just acrylic resins.
Most polyurethanes are actually polyurethanes of some sort. Everything else is often a wacky mix.
> Some carvers use urushi lacquer which is the sap from a tree common to Japan.
Urushi is the name of the Japanese tree, Toxicodendron verniciflua (the genus formerly was named Rhus), and of the lacquer of which its sap is the main constituent.
The lacquer is also called urushiol (note, not urushoil), which is also the resinous substance found in other members of the Toxicodendron genus: T. radicans and T. rydbergii, or poison ivy; T. diversilobum and T. pubescens, poison oak; and T. vernix, poison sumac. The resinous oil is what causes allergic reactions.
Which finally gets to my point: What are the allergic affects of the tree, its raw sap, the liquid lacquer, and maybe for hypersenstive/reactive urushiol allergies, the finished lacquer?
I don't meant to be alarmist - people have been eating off urushi lacquer for centuries. I'm thinking more about working with it.
EDIT: For those interested in the scientific aspects of the resin, plants, and allergic reaction:
Aaron C. Gladman MD. Toxicodendron Dermatitis: Poison Ivy, Oak, and Sumac. Wilderness & Environmental Medicine vol 17 #2 (June 2006)
https://journals.sagepub.com/doi/10.1580/pr31-05.1
> Which finally gets to my point: What are the allergic affects of the tree, its raw sap, the liquid lacquer, and maybe for hypersenstive/reactive urushiol allergies, the finished lacquer?
The Wood Database can be a useful practical site for this sort of thing. I found [0], a page for a different wood which is said to contain the same allergen:
> The sap contains urushiol (the same allergen found in Poison Ivy), and can still be irritating to some sensitized individuals even after the wood has been dried, and sap can also seep through some wood finishes to the surface of the wood.
Same as poison ivy? Count me out if true: I react badly.
[0] https://www.wood-database.com/rengas/
The Wood Database? Thank you for once again reminding me how incredible the Information Highway once was, and could be.
I lament our detour onto the Commercial Highway.
It's still out there! It only _seems_ distant.
> What are the allergic affects of the tree, its raw sap, the liquid lacquer, and maybe for hypersenstive/reactive urushiol allergies, the finished lacquer?
Essentially the same as for any other urushiol.
I'm highly sensitive and had to ask my partner not to get into kintsugi with the traditional lacquers because even the tiniest spot of urushiol and I will be considering a trip to the burn unit.
I've gotten a very mild reaction from ~century old lacquerware but I wouldn't expect that to be common, once it's fully cured. And just because it's mild doesn't mean it's any less itchy, trust me.
see https://news.ycombinator.com/item?id=46268130
> What are the allergic affects of the tree, its raw sap, the liquid lacquer, and maybe for hypersenstive/reactive urushiol allergies, the finished lacquer?
Answering my own question, based on reading my own source more carefully (Gladman 2006 p.122):
The Japanese urushi tree, T. verniciflua, is among "plants containing uroshiol cross-reacting chemicals", which are described as follows (note that genus Toxicodendron is in family Anacardiaceae):
"Similar compounds found in other members of the Anacardiaceae family, as well as in several non-Anacardiaceae plants, can lead to cross-reactions and to an identical clinical picture (Table 2). However, dermatitis induced by these cross-reactors is rare compared with the frequency of dermatitis from Toxicodendron species. The allergens in the non-Toxicodendron plants listed in Table 2 are generally noncatechol phenols and resorcinols, and not the highly allergenic catechols in poison ivy, oak, and sumac. The hypothesis that early skin exposure to catechols may allow cross-reaction to other Anacardiaceae, whereas early oral exposure to phenols and resorcinols may induce tolerance, has been expressed."
Regarding the chemical composition, urushiol (in poison ivy/oak/sumac): "is a mixture of 3-n-pentadecylcatechols, which contain a catechol ring moiety substituted with different aliphatic side chains at position 3 or 4."
Some people react very badly, some are immune. But to be honest I just don't like my spoons and cups to look lacquered and I don't prefer the process of application.
Nothing wrong with that though, I like reading and watching people do the process and seeing them enjoy the calmness in doing dozens of layers over multiple days. Some end up with very beautiful shimmery brown wooden pieces [0] and I would love to own some of them. It's just not my style.
[0] https://www.youtube.com/shorts/j1YHhsHZOGk
If you're interested in Urushi, here's an account from an artist who went to Japan to learn how to work with it - https://garlandmag.com/lacquer-god/
"Essentially a concentrated form of poison ivy, uncured lacquer causes blistering rashes which cause its sufferer almost unbearable itch and many sleepless nights. Building tolerance typically takes up to two years and has students living in constant fear of the very material they eventually hope to use on a daily basis."
Ouch. Rereading my source above (Gladman 2006), they say hyposensitization (desensitization, if I understand correctly) generally doesn't work, but ...
"Lasting natural hyposensitization has been reported, however, among Japanese woodworkers who use lacquer derived from Toxicodendron verniciflua, the Japanese lacquer tree. In a 1991 survey, 81% of craftsmen developed dermatitis from the lacquer but 83% of these reactions resolved with continued exposure."
As a child, my grandmother once accidentally used a poison oak stem to roast a hotdog over a campfire. She hadn't cooked it hot enough to denature the oil, and she reacted to it internally, which required a hospital visit.
Granted, consuming it is the worst-case scenario, but exposure to those oils can be life threatening.
There are people eating poison oak salad to try to make themselves immune:
https://www.wsj.com/style/eat-poison-ivy-oak-immunity-3207ec...
> There’s also Rubio Monocoat and other two-component hardwax oils where the base component is usually a solvent-free blend of drying oils and waxes, and the accelerator component is Hexamethylene diisocyanate or HDI. The base component can cure on its own in about 3 weeks and the accelerator shortens the curing time to less than a day.
I find it bizarre that these finishes market the HDI component as an “accelerator”. It seems quite clearly to be a crosslinking agent — it’s a longish molecule with a rather reactive isocyanate group at either end. If you mix it with things it can react with, which likely includes both some waxes (those with hydroxyl groups) and some of the modified oils in “hardwax” oil, it will turn them into something akin to polyurethane.
Rubio Monocoat will cure into a different substance with the “accelerator” added than without it. In either case, it cures quite slowly and IMO has a nasty, penetrating chemical smell for weeks. I like how it looks, but the finish is not as stain resistant as many other options are, with or without the HDI.
P.S. the SDSes and some common sense suggest that this stuff is actually HDI oligomers, not plain HDI. The oligomers are rather less nasty.
P.P.S. Isocyanates are, AIUI, not persistently nasty, as they are too reactive. They react with water to form amines, and unreacted isocyanates will react with the amines to form polyurea, which is reasonably inert.
P.P.P.S. The “molecular bonding” stuff that Rubio talks about seems to be nonsense. The part A + part B mix will cure into a fairly hard and tough plasticky substance even if it’s a millimeter or two thick. Don’t do that — it’s not so easy to get the resulting mess off of whatever surface it cured on!
Author here! Since the article publishing, I have found a widely available finish that's very similar to what I'm doing called Walrus Oil Furniture Butter: https://walrusoil.com/products/furniture-butter
It's still a combination of polymerizing oils, hard waxes and resin, it's just different plants (linseed instead of tung, pine resin instead of damar etc.) Again, no solvents, people say it smells good.
I still have way too much tung oil, wax and resin around because I could only buy high quantities, so I guess I'll keep using my own finish for a long while. But I'd love to hear from others how the Furniture Butter fares for wooden spoons and cups.
I don’t have the time pressure, so I just use tung oil.
I throw it in a bag and vacuum seal the spoon (with tung oil) for a day or two, then remove, wipe, and let cure for a month.
The resulting finish is largely dishwasher safe for a year or so before I have to reapply. Without the vacuum sealing stage, it doesn’t last as long.
This is an interesting article, though I wish they had relaxed some of the requirements. Demanding something that both cures fast and is free of solvents seems unnecessarily specific. For hobby projects finishing on a tight deadline is usually not a high priority so longer cure times are an acceptable tradeoff. For larger scale or business oriented projects the use of a solvent can be fine because proper VOC protective gear is not that expensive.
Even for hobby work it’s not hard to get reasonable VOC protective gear or establish a fume extraction hood out of some cardboard and a cheap box fan next to a window in the shop space.
The author of the article has a woodworking business (linked on the bottom of their homepage: https://gospodaria.com/). So they do need fast turnaround times for profitability.
However, as they mention, they do this work from home, and they don't really have a good setup for VOC protection. From the article:
> In the winter months I carve indoors and have to finish the pieces indoors as well, and the horrible solvent smell fills my house for a whole day.
A jury-rigged fume hood will work if you're doing one item at a time, but it doesn't work if you're doing work in batches.
(I get the impression that the best next step for the author, would be to consider building themselves a humidity-controlled drying shed, which would live at least a few feet from their building's air envelope. Doesn't need to be anything fancy; build an ordinary shed, and then get the small-space HVAC equipment from e.g. a marijuana grow-tent supplier.)
I always wondered whether the wooden spatulas and spoons they sell at IKEA are safe to use. I never know what that wood was treated with or coated with.
Perhaps I’m naive, but buying from an IKEA (in Norway) or another big store feels less risky than buying something handmade.
Several people are involved in making every product at IKEA. At least one of them must be an expert in compliance. They can expect scrutiny and product recalls, fines and bad sales if they’re found out.
The one person making the hand-made spoon does not necessarily know all the environmental regulations that should be followed.
I had a ceramic coffee mug that I loved and used very regularly. I bought it at a fair from a local potter and it had a very unique glaze, lots of blues and greens.
A friend who is a potter saw me drinking out of it and said that the glaze looked suspicious. He said it looked loaded with heavy metals, and that I should probably not use it or at least get it tested.
At the time I knew a guy who worked in a lab that tested certain substances for hazardous materials. He was intrigued and brought it in to work one day, and later texted me asking if I wanted it back, because it was very likely leaching cobalt, lead, and cadmium, and it was probably also very mildly radioactive.
I feel much better drinking out of mugs from IKEA and other big name stores.
maybe. Or maybe they are just buying from China and trusting it to be good and not change formula once you accept the sample.
They are raw wood, unfinished. I usually give them a little sanding and a layer of beeswax - doesn't last very long but makes them feel new for a while :)
Well unless you are getting solid wood utensils (much more $$ and most aren’t) then you are starting with bamboo glued together with adhesives. So at that point if you are worried about the finish I’d be worried about the glues as well
I get solid wood (olive wood or other woods ) tools and I don’t finish them. But if I did I might just use beeswax
Cooking utensils are mostly one piece, otherwise wood glue is PVA, same as school glue, that's about as non-toxic as you can get. I'd be more concerned about some kind of supply-chain issue contaminating the raw wood - hopefully they do frequent control checks on the material.
They aren’t one piece. See the dark seams? https://www.everythingkitchens.com/totally-bamboo-all-natura...
These are strips glued together aka laminated. The binder is not PVA (which is water soluble and not suitable for the task), it’s most commonly a formaldehyde resin such as phenol- , urea- or melamine urea formaldehyde
That’s plain bambu, the dark areas are the nodes/rings in the plant.
I don’t build cutting boards myself, but have never heard of using anything but food-safe PVA glue. Those resins are used for laminating plywood etc, probably not even legal to use in kitchen utensils, at least in the EU.
Ikea sells solid wood spoons and spatulas starting at like $3.
I think all wood finishes are "food safe" once they're cured.
That is a terrible assumption to make. Regular lacquer for example does poorly under temperatures commonly encountered when preparing food and it’s basically a mix of solvents.
The solvents evaporate when the lacquer cures, right? A lacquered spatula or spoon could leach some plasticizers when heated up. But who on earth would go to the trouble of spray lacquering a spatula? It doesn't seem like a real concern. Wooden spoons from IKEA aren't gonna poison you!
It's not a terrible assumption - it's a requirement to sell a wood finish in the US/Europe.
Under temperature, sure, they differ a bunch. But in terms of food prep, no, they are all non-toxic and edible once cured.
Flexner's "Understanding Wood Finishing" has a section about "the myth of food safety" that pretty directly states that food safety isn't a serious concern for fully cured finishes.
I use wood only for my non-stick pans. Metal for the metal pans. I sometime put some olive oil on the utensils, but generally, I just use them, put them in the dishwasher, repeat, until they break. They are ~50 cents at Ikea. And so I don't eat any plastics anymore.
Of course, the article is about high end stuff, but I just want to put everything in the dishwasher. Which I presume you can't do with even the best coated high end utensils?
We also switched to wooden Cutting boards, I find them to be pretty annoying as they really go bad fast in the dishwasher and can be quite expensive. We just wash them with boiling water, a bit of soap every now and then.
Seems a little extreme to pour boiling water on wooden cutting boards to clean? Do you live in really cold and snowy place without much access to sunlight hours? Just washing them with soap and drying them in sunlight is all we do and it’s been good. We also don’t cut meat on the wooden board. I would use hot water if it were meat on the board.
Never put a wooden cutting board in the dish washer.
Never use boiling water. Use warm water and a little bit of soap.
Great blog post. I like the emd look of the experimental finish.
Couple of years back I went to all wooden spoons in the kitchen. My all time favourite is the most traditional of all: boxwood. This is what wooden utensils are made in my home country for centuries. It's light but dense, hard, and durable. It doesn't absorb color or smells easily as other hardwood. Beautiful too!
> It's light but dense,
What does that mean? It's tough enough that you can make it thinner? It dries out more fully? Or does "dense" refer to something other than density, like tightness of the grain?
It's indeed the tightness of the grain, but also volumetric density (975 kg/m³) is higher than oak or spruce. What I mean with light is, indeed you can make very thin utensils and they won't break, bemd etc so at the end the product is lighter than the obe made with a softer/less dense wood.
Boxwood was for centuries the choice of wind instrument makers because of its stability and hardness, which made it possible to create thinner more practical instruments (clarinets, flute etc). till humans discovered granadillo wood, which is as dense as boxwood but much more humidity and temperature stable.
Incredible analysis, great blog post! What’s wrong with using raw wood? Will that go bad quickly?
If you use the appropriate wood, you can wet and sand many times to get a smooth finish. You can burnish it (rub with hard metal) to close the surface well. But it will still stain and absorb smells, just to a lessor extent. You'll notice if you use the same spoon for coffee and tea, or the same spoon for curry and miso soup.
Why would you use a wooden spoon for those? I use wooden utensils for frying and stirring in metal pots and pans. Everything else is just the usual stainless steel type suitable for utensils.
I don't know either, but the article is about wooden coffee cups.
I don't have a problem. if they get a little funky I just sand them down. and let them soak in food-grade mineral oil for a while. same with cutting boards and butcher block tables.
When the wood fibers get wet they swell and become soft. When soft, the surface will be very sensitive to damage. Fibers on the surface will raise and then not return to their original position, causing surface roughness. Repeated cycles of wet/dry will cause cracks.
From experience, even the cheapest wood spoons won't bulge, as long as you don't leave them immerged in water for a long time.
Could that be because they are treated somehow?
They were likely treated with mineral oil, but the finish has been gone for a long time now.
Depending on the climate, it can go moldy very quickly.
Alin (OP), what a wonderful article. I've had the same problem and had given up experimenting for similar reasons to you. I'm now thinking to finish the cup I've half carved and have sitting on the shelf in the shed. Thanks!
Your shop looks great too. Others might enjoy folowing the link buried towards the bottom of the article.
Thank you for the kind words! Do try to finish your cup, it's a great experience both to drink from something made by your hands, and to drink from a wooden cup if it's finished well.
Make sure you do water popping after finishing the carving and sanding process. It's what makes the difference between wood that catches your lips and wood that feels like ceramic. The process is simple: sand with 600 or 400 grit, whichever you have, then get all the wood wet with water (faucet is fine), let dry completely (hairdryer helps), sand again with 600/400 grit and repeat about 3 times until wetting the wood no longer makes it feel rough.
Great advice thanks, and a new technique to learn too. When making walking sticks I usually go to 1200 grit, or 2500 where finish is really important. Finishing is my favourite part of the job, similar to your point about epoxy (why would you want to interface with a layer of plastic?)
The timing of this is sort of uncanny as it's been on my mind a lot lately.
Generally I use a beeswax and mineral oil finish, sometimes this other product I can't remember the name of made from flax oil.
I've been wondering why jojoba oil doesn't get mentioned more in these discussions, either in combination with something else or on its own? It's a wax but liquid at room temperature, and seems to be stable for a long long time, long enough at least that it would probably need some refinishing before it might go bad.
The problem with jojoba oil is that it doesn't polymerize or cure. It stays wet in the fibers. Nothing bad with that on wood that doesn't contact hot food and beverages.
But if you put wood treated with non-polymerized oil in a hot soup or if you pour hot tea into a cup finished with jojoba oil, the oil will get out of the fibers and into your hot liquid, the fiber will raise and the wood will start to feel rough after a few uses and start to get stained from your food and beverage.
I make wooden cups. I use water-based polyurethane out of a spray can to waterproof the interiors. I find it a lot easier to use than epoxy in almost every aspect.
For the exterior and for cutting boards, I use a hard wax oil I make from linseed oil and beeswax. It's easy to prepare and I usually provide a small cup of it to whomever I'm gifting the cutting board.
I reuse small, glass jelly jars with screw-on metal lids, about 1/2 a cup in size. You do need to leave a layer of water on top, though, because otherwise the top layer will polymerize and leave a rubbery layer you have to remove the next time you use it.
Can't a spatula be just untreated wood? Or some very light oiling just to reduce the absorption of food. And then solve the problem by disposing of them fairly often. They make a lot of heat in the fireplace since they've absorbed so much fat...
Team tung oil here. Wooden-handled knives and wooden utensils get a light coat and left outside on a nice day. Repeat for 3-5 days and you're good for at least a year or two, depending on how you treat the items. The coating needs to be light else you get a shellac/lacquer finish. I use Walrus brand, pure tung oil.
Doesn't make sense to use Osmo Polyx oil as the baseline when Osmo Top oil is the slightly friendlier and equally beautiful food-safe version.
Osmo Polyx is what I already had around from other wooden furniture projects, that's all. I try to not store too many cans of unused finishes around my house so I try to use what I already have first.
Top Oil indeed seems very similar to what I did (hardwax, drying oils, driers) but half of it is still white spirit solvent, which I'm guessing will give it the same smell as Polyx.
The closest thing I found to what I want is Walrus Oil Furniture Butter (https://walrusoil.com/products/furniture-butter) but I didn't know about it at the time.
Walrus product looks good. Here's another one worth knowing but may be difficult to acquire outside UK: https://workshopheaven.com/alfie-shine-hard-wax-polish-fragr...
I finished a bunch of cutlery handles with tung oil a bunch of years ago. I easily found a bottle of it at Lee Valley Tools. It was the polymerized type, which dried pretty quickly, comparable to oil paint or varnish. The finish was prety glossy. I just used a paper towel to apply several thin coats.
It should be noted that this article belongs to a series starting with "Woodworking as an escape from the absurdity of software" :-)
Taking the advice of a pro at my local makerspace, I finished a cutting board with filtered ghee. Has been great so far without turning rancid as i thought it might
The solution is, use a metal spoon.
Wood is great for serving spoons, I have some fancy French ones, you just never dishwash and every few months wipe down with grapeseed or canola oil.
For eating? Wood just is not a good material.
Russian wooden spoons, Khokhloma style in articular are pretty much food safe. One can find a finish recipe for those online.
This is great! I’m going to try the melting carnauba wax in tung oil one. I tried pure tung but it’s too matte for what I want.
I've been using pure walnut oil on wooden chopping boards. Anyone else had experience good/bad using walnut?
Thank you for selling your version online!
Dude already found the perfect thing, but wanted an excuse to play with random metallic driers and resins instead. Fine, but don't pretend it was necessary.
Just use a precision scale. Pharmacists give me side-eye when I mention cutting my medicine. No, I do small-scale epoxy mixing!Author here, it's not that it's not possible, it's just annoying to do. Indeed, two-component hardwax oils are close to perfect (although the resulting polymer is not ideal), but having to do the precise pouring and mixing, and trying to smear that thick blend onto the wood, hundreds and hundreds of times, is not something I want to do.
I want to enjoy the process of making the wooden utensil as much as I want to see the end result, hence my excuse to play with random metallic driers and resins.
I have only used Rubio once and didn't bother with accelerant at all. For my use case it worked out fine. Although it's the only time I've done any sort of wood finishing so take it with a grain of salt.
You're apparently referring to Rubio Monocoat.
What's wrong with metal spoons?
Nothing, I'm just not a metal worker.
Check out volvox and auro products
Works well for me
Wooden spoons are inherently food-safe. Do not put any coating on them.
Kids toys, wooden kitchen utensils etc. are to be sanded and used coating free. If you really need to close off the pores, burnish the surface.
Burnishing for spatulas for example can be done on a drill press. Just use a smooth rounded end steel bar and a low speed on the drill. You’ll have the concave part done in minutes. For the handle and convex part it’s usually easiest to burnish with a smooth steel rod and move the piece along the side. I can get my hard maple spatula burnished in under 15 minutes.
If you really want to keep the fibers from rising a lot post burnishing- water pop the wood, sand with 220, slightly dampen the wood again and then burnish.
I haven’t tried this but apparently you can automate the burnishing by using antlers/smooth stones in a rock tumbler.
Interesting, I'll have to give that a detailed read later. It might be applicable to 3D prints.
To head off the people who will jump up-and-down calling me paranoid for not considering untreated printed works food safe, and accusing me of accusing them of poisoning family & friends (in some circles the discussion can get more cantankerous than the vi/emacs thing!): you keep using printed things for food without treatment if you like, and I won't judge, but I prefer to remain paranoid because if printed items were food safe it would be a selling point and I don't see any manufacturers using food based examples in their advertising.
> To head off the people who will jump up-and-down calling me paranoid for not considering untreated printed works food safe,
I’ve been involved with consumer 3D printing for over a decade and I don’t recall ever seeing a conversation where anyone suggested 3D printer parts were default food safe. It’s one of the more common FAQs you see on 3D printing forums.
I'm obviously in the wrong groups on facebook.
Oh, there is some passion the other way.
I'm happy that the down-vote-y anger here is on the correct side! (unless you are the only one who agrees and the other downs are from the “how dare you suggest I might do something wrong” mob)