Is Tung Oil Food-Safe?

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Finish wood in the kitchen

One of the most common natural finishes is tung oil, an extract from tung tree nuts. It surpasses other oils in terms of durability, water resistance, and hardness. Its characteristics make it a good choice for applying it around the kitchen yet you might wonder: Is Tung oil really food-safe?

Once it is cured, pure Tung oil is generally food-safe. It’s actually a common oil for cutting boards, butcher blocks, wooden countertops, wooden toys, etc. However, some Tung oil brands contain chemical ingredients that require some caution. Therefore, to be on the safer side, wait up to 30 days for it to get cured.

Read on to learn more about the considerations around Tung oil and what you need to consider when buying off-the-shelf mixtures.

Different Tung Oil Finishes and Their Food-Safety

There are three different types of penetrating tung oil finishes. All of them might be labeled as Tung oil but their ingredients differ and some of them are more suitable for wood in the kitchen or children’s room than others.

The most common types are pure tung oil, Tung oil-based wiping varnishes, and oil/varnish blends. However, some manufacturers might not use such terms on their labels and just call their product Tung oil. You can distinguish them by reading the list of ingredients or their safety sheets.

Pure Tung Oil


Example of a pure Tung oil product.

The identification of pure tung oil is easy because it has no solvents, which means there is a minimal chance of getting exposed to the volatile organic compound (VOCs). Natural Tung oil is therefore non-hazardous and can be used where food-safety is required. This is also

However, a weakness of this type of oil is the burdensome application process. To get a robust protective film, the application of several coats (some recommend five coats or more) is required. It may also take a couple of days for it to fully harden.

Its application also requires some skill and experience. A thick coat can result in wrinkling. In that case, you would have to intensely sand it to get a smooth coating.

In any case, you will need to regularly re-finish the wood to retain the protective effect and the enhanced appearance.

The oil/varnish blend and wiping varnishes, on the other hand, are enhanced with chemicals that ease the application process and enhance the drying time and durability of a finish.

According to the US Food and Drug Administration (FDA), Tung oil is generally deemed food-safe (source). However, its use in food packaging requires a letter of no objection issued by the FDA (source).

Oil/Varnish Blends


Example of an oil/varnish blend product.

These Tung oil blends consist of a mixture of Tung oil and solvents (e.g. mineral spirit). They have been developed for making the application easier and to speed up the drying time. You will know it is oil/varnish blend once you see ‘contains petroleum distillates’ on the sheet label.

While this increases the convenience of its application,  it also means that you should be careful in applying it to areas that get in contact with food. According to the US Food & Drug Administration (FDA), Code of Federal Regulations, Title 21 (link to the document), it is generally deemed food safe once it is fully cured though.

During the curing, it may evaporate smelly or even unhealthy fumes, depending on the type of solvent used as an ingredient. Therefore, adhere to the instructions on the back of the can for the recommended curing time. To be on the safe side, you can add a few additional days.

Wiping Varnish


Example of a wiping Varnish for applications around the kitchen.
For such products, refer to the SDS sheet to find out which solvents and ingredients have been used.

Wiping varnish is an oil-based finish that comes with mineral, soybean, linseed or Tung oil that is cooked with resins. Its advantage over pure Tung oil is the faster drying time, the improved resistance and the easier application. These varnishes contain a thinner that allows for wiping them with a cloth, hence the name wiping varnish (source).

Although this product may be labeled as ‘Tung oil finish’ or similar, you can find out whether it is a varnish by checking the ingredients: If it also contains petroleum distillates it is a wiping varnish rather than pure Tung oil.

Similar to other oil/varnish blends, wiping varnish is food-safe once it has fully hardened. However, during the oxidation process, hydrocarbons and aldehydes get released in low concentration – so low though that they do not pose a considerable health risk for a healthy person. Yet, it may be considered unpleasant or even hazardous for an allergic person or one with severe preconditions.

Which Tung Oil Finish Should You Choose Considering Food-Safety?

Although there is no doubt that the Tung oil tree is poisonous (source), it is also true that the Tung oil itself is non-toxic. FDA has approved the use of pure tung oil finishes in surfaces that are in contact with food that includes kitchen tables, furniture, chopping boards, and others.

Non-hardened Tung oil may, however, cause allergic reactions in very rare cases. Therefore, wood treated with Tung oil should only be brought in contact with food when it has fully dried.

Tung oil is often thinned with solvents, either during the application or as an off-the-shelf varnish. While it is still food-safe when it has fully cured, it is even more important to allow for sufficient drying time and store the treated object apart from food and children (e.g. in a workshop). Depending on the solvents used in such blends, smell and unhealthy fumes can occur during the curing period.

Before choosing a specific type of oil finish, there are many things that you should consider before making a decision. This includes:

  • FDA assessment of the food safety of a cured/hardened finish,
  • its curing time, and
  • health risks during application and curing.

Using pure Tung oil without any solvents should be the ‘food-safest’ way to finish wood with Tung oil. However, the application of non-thinned Tung oil is quite burdensome, may affect the appearance and requires long drying time. That’s why oil/varnish blends and wiping varnish have become popular over the years, however, they achieve food-safety only when they have fully dried or cured.

However, there are also other food-safe wood finishes that you may want to consider as well. We are providing an overview of alternatives to Tung oil in the following section.

Comparison with Other Food-Safe Finishes

Besides Tung oil, various other oils and waxes are also food-safe and can also be used as wood finishes. In this section, we compare pure Tung oil with mineral oil (a popular alternative) and beeswax.

Pure Tung Oil Wood

This oil provides a beautiful and resistant finish but it’s hard to apply if it is not mixed with solvents. Its characteristics include:

  • FDA approved
  • Creates a resistant waterproof finish
  • Zero VOCs
  • Natural polymerizing
  • Resists acids and abrasions

Mineral oil

Mineral oil is one of the best food-safe oils for finishing wood. They are transparent and bring out the wood’s natural appearance. Mineral oil is

  • FDA compliant
  • Relatively odor-less
  • Can even be used for skin treatment
  • Made from distilled petroleum and other minerals
  • Available in refined and crude products
  • Requires regular maintenance

Read more in our article on mineral oil.

Beeswax

Beeswax has been a versatile natural material for centuries. It can also be used as a polish or finish for wood. It is an excellent food-safe oil finish because it is natural and lacks harsh chemicals. Compared to other finishes, it requires lots of work though. It should be melted or mixed with oil for its easier application. Other characteristics are:

  • Non-toxic (source)
  • Provides less protection than other finishes
  • Needs regular reapplication
  • Works perfectly with additional lemon as an antibacterial agent

Another alternative is Danish oil which is also food-safe. Read more in this article where we discuss the details.

Conclusion

Tung oil is a food-safe wood finish that can be used in the kitchen and children’s room. However, it should have cured properly which is even more important when it is mixed with solvents or when an oil/varnish blend is used. Using pure Tung oil is probably the best choice when it comes to food safety. However, it is hard to apply without a solvent while solvents may add unhealthy ingredients to the mixture.

There are some other alternatives, such as mineral oil or Danish oil that could be a good choice as well. If you want to learn more about their characteristics, read this ultimate guide to oil as a wood finish.

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