The Literary Workshop Blog

Although I don’t make a lot of spoons these days, I still haunt the spoon-making discussion groups on social media, and this is one of the most common questions I hear. How can you be sure that the wood finish you’re about to use is actually food-safe?

Here are some freshly-finished utensils made from eastern red cedar. Dust from this wood is a known irritant, and the oil finish hasn’t been officially certified as food-safe! Will they poison everyone who cooks with them?!? No, they won’t.

Let’s say you’ve made a cutting board or a wooden spoon, or maybe you’ve built a baby crib, and you want to be extra-sure that the finish won’t poison somebody.

You go down to the home center and start looking at wood finishes, and only a few (mostly expensive oil-based finishes) make any claims to be safe for food contact. What about the rest of them? Can you safely finish that cutting board with Danish oil? If the baby if starts chewing on the crib rails, will a lacquer finish send her into anaphylactic shock? Why on earth don’t companies tell you if their product is or isn’t toxic when cured?

Or maybe, just maybe, we don’t get the answers we want because we’re not asking the right question.

In a classic article, finishing expert Bob Flexner points out that no government agency actually certifies any wood finish as “food-safe.” A company can call its finishing product “food-safe” at its own risk, but that claim has not been verified by anybody.

So does that mean that there’s no safe wood finish on the shelves today? That only raw, unfinished wood is truly food-safe?

Not at all. Here’s what Bob Flexner has to say:

…there is no evidence of any common wood finish being unsafe for food or mouth contact once it has fully cured, so a distinction between food-safe and non-food-safe is speculative.

You can’t be absolutely sure about the food safeness of any finish you put on wood. There could even be problems with mineral oil and walnut oil that we just don’t know of yet. There could also be problems with raw linseed oil, pure tung oil, wax, shellac and salad bowl finish, because we don’t know where these substances have been or what they might have come in contact with. None has met the regulations laid out by the FDA.

But, based on FDA regulations, the way finishes are made, the complete lack of any evidence to the contrary, and the countless other untested objects food and children come in contact with, there’s no reasonable argument for avoiding the use of any finishes.

(The whole article is worth reading in full, though it’s only available on web archive sites now.)

In other words, the question we should be asking ourselves is this: “Which wood finishes are known to be toxic when cured?”

And the answer, at least in the USA, is “none of them.”

According to Bob Flexner, there are some specialized commercial finishes in some industries that come with health hazard warnings, but they aren’t the kinds of products you can find on the shelves at your local home center.

When you think about it, we come into contact with various cured wood finishes pretty frequently–on wooden floors, wooden furniture, wooden paneling, wooden handles, you name it. Have you ever heard of anybody reacting negatively to handling finished wood? I haven’t. Our common experience indicates that, as far as anybody knows, none of the the wood finishes you can usually buy off the shelf at a home center in the USA are toxic when fully cured. (Check the label. Is there a warning that the finish contains heavy metals, like lead or mercury? No? Then you should be good to go.)

That’s not to say that applying finishes is non-toxic. Many common finishes, like lacquer, give off pretty noxious gasses as you apply them. Others, like boiled linseed oil, can cause fires if oil-soaked rags are improperly stored. So you should always take reasonable safety precautions when applying a wood finish. But once the finish has cured, the finished wood is as safe to handle as any other common object in your everyday environment.

There are even a few wood finishing products that are edible: shellac, beeswax, mineral oil, and vegetable oils (e.g. flaxseed oil, hemp oil, and walnut oil). Some purists stick to these products in older to be double-extra, super-safe. I have also known people to just use whatever vegetable oil they have available, like olive oil or sunflower oil, but that’s a mistake because those vegetable oils don’t actually dry. If it doesn’t wash right off of the utensil, it will eventually go rancid. So if you absolutely must use an edible finish, stick with an oil that dries: flaxeed/linseed, hemp, or walnut oil.

For my own wooden spoons and spatulas, however, I use a three-part blend of polyurethane, mineral spirits, and raw linseed (flaxseed) oil. The oil and polyurethane mix and dry in the wood, and the mineral spirits (added only to thin the mixture so it soaks into the wood) evaporate completely.  The finish is extremely easy to apply, and once it’s cured, it stands up to repeated washings in the kitchen. And it has never, ever poisoned anybody who used a utensil that was finished with it.

So yes, it’s fine to finish your cutting board with the boiled linseed oil from your local home center. Just let it dry completely before you start chopping fresh veggies on it. And yes, go ahead and use lacquer or polyurethane on that baby crib.

Unless it’s the mother’s first baby, and she’s a health nut.

In which case, give that crib a coat of food-grade flaxseed oil followed by several coats of shellac topped by a hand-rubbed coat of beeswax. Tell the anxious mother that while the finish won’t exactly be tasty, it is certifiably edible.