Tag: Oil & Paint

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.

If you’re the kind of person who loves to use their woodworking skills for something practical then you’ve probably put together some sort of cooking utensil or cutting board at some point. When you’re treating something that is used with food you need to use non-toxic and safe products. Here are two of the most well-known food-grade finishes for your wooden crafts: Mineral oil and linseed oil.

So, what differentiates these two oils from each other? They may seem to have a lot in common – food-safety, in particular – but when you compare them you see some differences: Linseed oil is more water-resistant but harder to apply while mineral oil is cheaper and retains the original color of the wood.

We’ll take a moment to go over all the information about both in detail and let you be the judge of which one is best.

What is Linseed Oil?

Linseed oil, or more specifically raw linseed oil, is a nondrying oil. Also known as flaxseed oil, it is used for treating wood, mixing with oil paints and even in food for its excellent nutritional values.

This oil comes from the flax plant. It’s extracted by pressing fully ripe flax seeds until the oil comes out of them. If you’ve ever seen a field full of those bright blue little flax flowers, that’s where this oil starts its life.

Variants of Linseed Oil

There are variants of linseed oil other than the raw kind, but in this article, we will be covering raw linseed oil, as there are some differences between them. One of the main differences is that raw linseed oil is a nondrying oil and the others, such as boiled linseed oil (source), are generally drying oils.

Read more about boiled linseed oil in this article where we also discuss its differences to raw linseed oil.

Linseed Oil and Food-Safety

Raw linseed oil is a big favorite among eco-conscious woodworkers. This is due to the fact that it is a 100 percent naturally sourced oil. The FDA has approved raw linseed oil as a food additive and it’s totally non-toxic (source). What this means is that you can safely use raw linseed oil to finish your chopping boards and wooden spoons alike.

Application of Linseed Oil

This is a really slow-drying oil, definitely not one we’d recommend if you’re in a hurry. Good things often take time and the finish you get from linseed oil is especially beautiful. The slow dry time allows the oil to smooth itself out and reduce the number of visible brush marks.

You can mix linseed oil with mineral oil to thin it down (source). This makes it a little easier to work with and allows it to penetrate the core of the wood more easily.

Remember to always check the product packaging before purchasing linseed oil. Some manufacturers mix linseed oil with chemicals that might affect its food safety. You want to ensure you are getting the right type.

What is Mineral Oil?

Mineral oil can actually refer to a few different oils, although they’re all very much alike. It’s a non-drying oil that is completely transparent, produces no smell and leaves behind no taste. It has a wide range of uses, from woodwork treatment to the production of makeup, it’s even used as a lubricating element in engineering.

The story of how mineral oil gets made is quite fascinating. It’s actually a byproduct of the petroleum refining industry.

Mineral Oil and Food Safety

Not to worry though, it’s completely non-toxic. The oil is taken through a strict distillation process (source) to ensure it’s totally food safe. Read more about its use with food in this article.

Application of Mineral Oil

Mineral oil might just be the easiest to use for wood treatment on the market. You don’t need to thin it down or add anything to it. You can apply it directly to whatever you’re making. Professionals and beginners alike will find the ease of use to be very convenient.

A lot of people like to use mineral oil to treat their woodwork due to the fact that it leaves a very natural look to the finished surface. Generally, mineral oil will not affect the color of the wood much at all.

One of the nicest things about mineral oil is that you can get your hands on it very easily, it’s very reasonably priced too. It’s also worth mentioning that mineral oil is non-toxic and produces a food-grade finish, meaning that there’s no danger in applying it to chopping boards or other kitchen tools.

Keep an eye out for the label before you buy any mineral oil. Typically, the one you want will be called “white mineral oil”. They’re not all food-safe, so it’s important to keep tabs on this.

Differences between Linseed Oil and Mineral Oil for Wood Finishing

When you’re choosing a finish for your woodwork you need to decide just exactly what you’re trying to achieve. Are you going for a traditional look or more of a contemporary one? Does it need to be done fast? Once you know these things you’re ready to choose the right oil.

Even though both of these oils behave quite differently, they’re both non-drying oils. That might sound a little confusing, but we’ll explain everything.

Mineral oil is great for creating a finish that shows off the natural beauty of the wood, but it is a little bit less durable than what you can achieve with linseed oil. One of the downsides of mineral oil is that you do need to go back and touch up the finish occasionally. Evaporation is a little bit of an issue for mineral oil-based finishes and they do just need that extra maintenance. Mineral oil doesn’t tend to do that well with liquids either, it’s not very waterproof. One of the advantages of a consistently maintained mineral oil treatment is that you’re replenishing moisture that helps stop any cracks from forming in the wood.

On the other hand, linseed oil is still a non-drying oil but it creates a radically different surface. You will absolutely need to build this up in thin layers if you want a strong coat, a thick layer of raw linseed oil can take forever to dry. You do get a much smoother and more refined-looking finish for your efforts though.

Both mineral oil and raw linseed oil are very easy to come by. Neither oil is especially expensive.

Mineral oil is generally considered to be the easier one to use of the two oils. It’s less picky about layers and doesn’t take forever to dry. Linseed oil may be a little tougher to use, but the results you get from it produce more richness in the finish of the wood.

Conclusion

Whether you choose mineral or linseed oil, at the end of the day it’s a balance between which appearance you prefer how much time you can spend on the application and if the surface needs to be water-resistant.

You don’t have to worry about food safety with either of these oils, they’re both non-toxic. That means that you can happily use them on any wooden bowls or utensils that you’ve got your eye on.

Whichever suits you best is still going to produce attractive results. Make sure you also check out this article where we compare mineral and linseed oil with other common types of oil.