Is Tung Oil Foodsafe?
When we started making our range of wooden kitchen utensils we spent a lot of time researching what would be the safest coating to use.
We discovered that Tung Oil is completely food safe and this data is supported by the FDA.
Our research had several angles to consider both from a business sense as well as for safety. The research proved that
- Tung oil is Foodsafe.
- Tung oil is easy to care for.
- Tung oil is easy to repair if need be.
- Tung oil is simple to apply.
The time spent researching Tung Oil was a good investment because our research showed conclusively that Tung Oil is the safest and best finish we could use.
We learnt that it is an oil that soaks into the pores of the wood before it cures if applied correctly. This allows the oil once it has cured to become a part of the wood therefore it doesn’t sit on the surface just waiting to be scratched off. It cures 100% hard so there is no risk of it becoming rancid that many cooking style oils have a habit of doing. It simply outperforms most common surface coatings when it is applied to food preparation tools.
Here is some data for the nerds.
From the US FDA website.
“Resinous and polymeric coatings may be safely used as the food-contact surface of articles intended for use in producing, manufacturing, packing, processing, preparing, treating, packaging, transporting, or holding food, in accordance with the following prescribed conditions:
(a) The coating is applied as a continuous film or enamel over a metal substrate, or the coating is intended for repeated food-contact use and is applied to any suitable substrate as a continuous film or enamel that serves as a functional barrier between the food and the substrate. The coating is characterized by one or more of the following descriptions:
(1) Coatings cured by oxidation.
(2) Coatings cured by polymerization, condensation, and/or cross-linking without oxidation.
(3) Coatings prepared from prepolymerized substances.
(b) The coatings are formulated from optional substances that may include:
(1) Substances generally recognized as safe in food.
(2) Substances the use of which is permitted by regulations in this part or which are permitted by prior sanction or approval and employed under the specific conditions, if any, of the prior sanction or approval.
(3) Any substance employed in the production of resinous and polymeric coatings that is the subject of a regulation in subchapter B of this chapter and conforms with any specification in such regulation. Substances named in this paragraph (b)(3) and further identified as required:
(i) Drying oils, including the triglycerides or fatty acids derived therefrom:
Castor (including dehydrated).
End of Quote
We have cut the list at this point and if you are interested here is the link to the FDA data.
Once cured, Tung oil in its pure form is food safe and is even safe for kids toys as well along side your wooden kitchen items like rolling pins, spoons, spats, and spurtles. We don’t recommend it for cutting boards as knives will very likely slice through the oils protective barrier over time and allow moisture to penetrate into the wood potentially staining and possibly splitting the board. Our recommendation is not about safety in this case but more about looking after the board for a longer life. This is primarily applicable to edge grain boards.
End grain boards are a different subject and will be addressed in another article.
Is it easy to care for?
Oh, yes it is. We have a kitchen full of the same utensils we offer here on this website and they are all coated with Tung oil and this is for a couple of reasons. The first is to discover how this finish holds up over time with use…(and some deliberate abuse..) and the second is to gain knowledge on the design aspects; how can we make these better. If we won’t use the item, why should we ask you to consider it?
We can state categorically that this finish will hold up to normal use for years….with an added disclaimer that no dishwashers are used. When it comes to any wooden kitchen utensil be it a spoon, a bowl, or a cutting board…..don’t put them in the dishwasher. If you do this you have ventured out of the kitchen cooking department and have stumbled into the steam-bending of timber department. This will not end well.
To clean your spoon or rolling pin, warm soapy water in the sink with a dish cloth is sufficient. If stubborn food residue plays hard and needs some persuasion a scourer is ok to use, just don’t use it if it’s not required.
A quick side story….This is where the “deliberate abuse” comment above comes into play.
At home here, we have several wooden bowls that we turned on the lathe and coated with Tung oil. These bowls are mostly used for breakfasts and are used daily. They are scrubbed with a scouring pad every morning and this has been going on for at least 18 months. The image of the bowl is one of these and the inner surface is still intact and stable, and it has acquired an aged patina. This bowl is at least 18 months old and has been cleaned daily with a scourer. When it comes to drying the item either drip-dry or wipe down with a tea towel. We have found zero evidence of watermarks left behind after drip-drying on a daily basis.
I don’t have tung oil available to recoat my utensil, can I use a different oil when it needs treatment?
We discuss this very topic with our clients at face-to-face markets.
Yes, once the surface of your spoon, spat, or stirrer becomes jaded you can use a different oil to bring it back to near new. There are a few guidelines to be aware of before you rush off to the pantry and grab the first oil you find. Many of the cooking oils never actually harden so they have a habit of going rancid. The oils that we suggest are the drying oils and the short list would be something like this..
- flaxseed oil
- poppyseed oil
- linseed oil (flaxseed re-named)
- Grapeseed oil
These are the common oils usually available. We recommend buying from the healthfood department or store as this is making sure it is food grade. Hardware versions of linseed oil often have additives that may not be safe.
We suggest checking out the FDA link above as it lists other oils that may already be on your shelf at home.
Ok, I have some oil ready to go. What should I do next?
This is very simple and it’s one of the reasons we use this finish in the first place.
You need a clean fresh dry scouring pad and a paper kitchen wipe.
Make sure that the item to be treated is dry and clean. Take the scourer and scratch the surface of the wood firmly. You don’t want any gloss patches at all. A dull matte look tells you that you have a surface where the new oil can bite into the old surface and “key in”.
Once the surface is dull take the paper towel/wipe and apply a good coat of oil to the surface. Leave it sit for 5-10 minutes and wipe off the excess then put the tool aside somewhere safe for a day or so. The longer the better as some of the oils we listed above can take some time to cure. If you want to apply a second coat then apply it after 12 hrs or so generally speaking. Two thin coats will be better than one thick coat. Every oil will be different and your environment will be different to everyone else. The trick is to just let it harden before putting it back into use.
Below are a few of the utensils and products we have made that are finished with Tung oil. It really is our go-to finish for quality. The vases come with us to the Yungaburra markets once a month and are stroked and caressed by dozens of people, mostly women. They seem to have an innate connection with these vases, moreso than males for some reason. It’s beautiful to see and very heartwarming.
A word of warning.
Not all Tung oil products are equal or natural. We use 100% pure Tung oil and thin it down as we go depending on the task at hand.
The thinner we use is D-Limonene, a natural product created by distilling citrus peels. This product should be treated with caution around children and animals and saftey directions should be followed as with all volatile products.
The citrus aroma is slightly pleasant and not offensive at all. It also make a good cleaner but that’s another story for another time.
The D-Limonene evaporates completely leaving you with a natural result. It is environmentally sound, and ethically derived as well.
Hardware stores supply Tung oil finishes as well but most of these finishes are designed for floors and bench tops. They have a smaller amount of Tung oil and by using other oils they can give harder wearing properties. These other oils usually require hardeners and dryers; in some cases heavy metals are incorporated to achieve the hardness and drying times they need as a commercial high wear finish. This is not a criticism of these products, it is just a heads up so you understand the difference between the different types. The pure oil finish is food safe but we cannot say the same about the floor finish mixes.
So, to finish this article up, there is enough information and data out in the public sphere to recognise Tung oil as a food safe finish.
We test the items that we sell before they are offered to the public and this finish passes the highest test.
We love it.
How do you apply Tung oil as a food safe finish.
This section will detail the method we as professional woodworkers employ to apply this finish to a raw product.
These steps apply to all items in a similar way with size being the only difference.
When we have completed the shaping we sand the item to at least 400 grit. This is our absolute minimum before we can apply a first coat and depending on the item, we will sand up to 600 grit first.
The oil is cut (thinned) depending on the wood involved with very hard wood recieving a 50/50 mix of oil to thinner. A softer wood may get a 70/30 mix. Experience over time will teach you the best mix for the wood in question. This first coat is applied generously and allowed to soak in for 5-10 minutes. Resist the temptation to load up the grain with oil to save time. This causes the oil’s surface to cure and can leave the internal layers of oil to stay in a gel state for quite some time and it can lead to bleeding out in bad cases. Once the time has passed, the excess is wiped away leaving a moist look without any runs or pools. This is allowed to harden for as long as possible with 24 hrs as the minimum.
A second coat of 80/20 is then applied but this coat is now rubbed in with wet and dry sandpaper and the excess wiped away. This mix applies to all woods as the initial different ratio coats will act as a sealer and grain filler layer and will act pretty much the same if you followed step one correctly. If unsure on soft woods then just apply another coat of the same first mix and then apply the above 80/20 mix as described.
The grit used in this second step is one grit higher than the final grit used in the sanding process. If 400g was the last for sanding then 600g is used. If 600g was the last for sanding then 800g is used. This wet and dry rubbing process creates a natural grain filler that disappears into the colours of the item and allows for a wonderful smooth finish that you can be confident of lasting. It will be prudent to let the piece sit for 24 hrs before handling to avoid any surface issues and another 24-48 hrs to let it harden enough to move around. Depending on your climate and humidity it may take longer to achieve a good outcome but it will happen. You can continue to apply coats as you see fit, but understand that it can be overdone if you are after a classic oil finish. We find 3 coats enough on most items, and apply a wax polish blend over the more artistic items.
This article is by Tim Blanch.
He is part-owner-operator of Pickers Ridge Hardwood Designs.