What Wood Treatment Is Food Safe?

What Wood Treatment Is Food Safe?

With all the many factors in play when it comes to choosing a wood coating (colour, durability, price, resistances), you can often forget about the many hazardous chemicals at play in particular coatings. While most of the time this isn’t a health issue (so long as you’re careful when applying them), there are certain occasions where these useful chemics (biocides, carcinogens, etc) pose an imminent health risk. Perhaps you have young children or pets in the house, and you’re worried about their safety? Or maybe the product you’re looking to coat will come into regular contact with food items, such as chopping boards, salad tongs, or even wooden cutlery. 

Most wood coatings aren’t rated food-safe, and can therefore be very dangerous to apply to wooden kitchen items. Food safety standards in the industry are exacting, and a lot of ‘natural’ products you’d think would be safe actually aren’t. However, there are a number of products available on the market that are, each with their own benefits and issues as coatings. Let’s compare some of them.

Qualities:

  1. Entirely food-safe, free from toxins, and professionally certified for a wide number of products;
  2. Water-resistant, and dirt and dust can be easily removed;
  3. Easy to apply;
  4. Use of other Treatex products (Wax Polish, hardener) can clean and strengthen it without much extra effort. 

Problems:

  1. Make sure not to over-apply the oil (follow manufacturer’s instructions);
  2. Relies on ventilation to dry more than other coatings;
  3. If the product needs to be hard-wearing (like flooring), you’ll need other products to clean (Wax Polish) and strengthen (hardener) that are not food-safe.

In terms of a professional-grade, high-quality treatment, Treatex’s Hardwax Oil Ultra definitely stands out from the pack. Whilst still retaining food-safe credentials (having been cleared for use with children’s toys and food items) and being completely free from biocides, preservatives or carcinogens, the Hardwax Oil brings in some of the consistency, durability and reliability you would expect in a professional product. 

While many of the products listed here might take a good day or so to dry, the Hardwax is very quick drying (taking only an hour if you buff it, and three to six if you leave it). It’s very water-resistant, can be applied by buffing, brushing, or rolling, meets with emissions regulations, both dirt and dust wipe away easily, and it’s very temperature-resistant. This mixture of qualities has made it a desirable product for craftspeople, and it’s been used for a whole range of artisan products that you might only ever have considered natural coatings for before (most notably cutlery, plates, cups, and other items with heavy contact with food and drink). 

Of course, making a professional-grade product like this entirely food-safe came with some challenges. When speaking with Neil Clark, Sales Director of Treatex, about the Hardwax Oil, he had this to say about the process:

‘We spent a lot of time making sure we had all the relevant certificates, including Safe for Children’s Toys. The Food Certificate was more of a challenge, as very few laboratories are set up to run tests. We only found one that would undertake the intensity of testing we required. The tests involved submerging treated samples in various liquids (which were substitutes for compounds found in food, but at a much higher concentration) for up to 24 hours. The liquids were then tested to see if any of the Treatex had leached out. 

Treatex Hardwax Oil Ultra passed these tests with flying colours – and unlike our competitors, we at Treatex are happy to display all the certificates on our website.’

The combination of sustainable oils that make up the wax contains many of the other coatings seen here in this list, granting it many of their strengths whilst not suffering from some of their unfortunate drawbacks. However, do be careful to not over-apply the oil on whatever surface you’re treating, as that can increase the drying time; just one coat should be enough. The oil’s drying process is also reliant on good ventilation more than some of the other methods listed here, so make sure you can get good air-flow over the room you’re coating. While the Hardwax Oil can also be easily strengthened or cleaned through other Treatex products (Wax Polish for cleaning, hardener for strengthening), these other products are not rated food-safe, meaning that you’ll need to be careful when maintaining kitchen items.

Qualities:

  1. Entirely food-safe, free from toxins, and safe for food and children’s toys;
  2. Water and spillage resistant;
  3. Breathable finish;
  4. Durable, hardwearing, and craftsperson-approved;
  5. Available in a wide range of colours.

 

Problems:

  1. Only rated for kitchen worktops and interior joinery, limiting its use;
  2. Requires other products for maintenance which aren’t food safe;
  3. Preparation of surface is more complicated, and product takes longer to dry;
  4. Suitable only with a smaller range of timber choices.

 

Much like Treatex’s Oil, this product is similarly well-regarded as a food-safe coating option, and is equally used and regarded by craftspeople as an effective, high-quality preservation option for wood crafts that come into ready contact with food. Unlike the Hardwax Oil Ultra, which is available in a small range of sheens, the TopOil comes in a diverse range of finishes. It’s similarly water-resistant, resistant to liquid spillages, has a breathable finish (reducing the likelihood of cracks in the coating), and is tested for food safety and applicability for children’s toys to the same standards as Treatex. 

However, Osmo’s TopOil comes with some other issues that Treatex doesn’t have. While the Hardwax Oil is applicable to most indoor wood items (floors, doors, stairs, etc), the TopOil is rated only for wooden kitchen worktops and interior joinery, making it a little less generally versatile. It also requires other products for consistent maintenance, such as Osmo’s Spray Cleaner and Liquid Wax Cleaner, which are not food-safe. Preparing the surface for TopOil and maintaining it is also a much more involved process than with Hardwax, and the product takes longer to dry upon coating. The central issue, however, is that while the Treatex product is cleared for all timbers, TopOil is not recommended for a wide number of timbers, including common furniture woods like mahogany and cedar.

Linseed oil

Qualities:

  1. Deep penetration;
  2. High level of protection (scratch and humidity);
  3. Brings natural sheen to many wood types;
  4. Works well with wax.

Problems:

  1. The most effective type of linseed oil is BLO, which isn’t food-safe;
  2. It requires fairly consistent re-oiling.

Linseed oil is a very popular hand-rubbed wood finish, which, when applied, permeates deep into the wood grain. This grants the wood a high level of protection against scratches and changes in humidity. Prior to the invention of synthetic resins, linseed was often considered a default wood finish; but now, with many homeowners looking for non-toxic options for wood protection, linseed is seeing a modest revival. Linseed has the potential to provide a high-quality finish for your wood products, as it can bring out the depth of colour and texture in wood grain with its natural sheen – a sheen that can be enhanced further by use of wax (see below).

Linseed oil comes in three distinct types – Raw, Polymerized, and Boiled. Raw linseed is itself used in nutritional supplements, and is distinctly food-safe. It provides a great finish if layered thinly, but takes a while to set in. Polymerized oil, which has been subject to rapid heating over several days, has an increased viscosity and takes less time to dry, while still being equally food-safe. Boiled Linseed Oil (or BLO) contains toxic drying agents, which make the oil more applicable for treating wood furniture due to it drying much faster; however, doing so makes the oil not food-safe at all, and it can emit unsafe compounds while drying. 

However, linseed oil does have certain problems. It requires fairly consistent re-oiling, is susceptible to water rings (marks left by wet glasses or mugs) and can stain if it’s subject to spills. Also, changes in temperature and humidity can cause the oil to run. It’s a great product to use if you don’t mind re-oiling the item fairly frequently. Keep to polymerized (if you want it food-safe) or BLO (if you just want the colour properties) for the best overall results.

Vegetable Oil

Qualities:

  1. Naturally protective against scratches, dust, mould and rot;
  2. Entirely food-safe (and very edible);
  3. Cheaply and easily available everywhere, and easily to ethically source;
  4. A good base to later apply paint.

 

Problems:

  1. Can easily stain wood if applied poorly;
  2. Often attracts dirt and dust;
  3. Requires more frequent maintenance, and even stripping and re-applying;
  4. Darkens lighter woods over time, making it unsuitable for certain timbers.

 

Vegetable oils, including soybean oil, rapeseed oil, and olive oil, can very much be used as a wood finish. If applied properly, the oil can have a natural protective effect, drying quickly and providing scratch and dust protection, as well as some basic protection against mould and rot. It’s also, as you might imagine, cheaply and easily available at any given supermarket, and easy to source sustainably and ethically. If you’re planning on painting the wood, it can also help paint adhere to the surface better.  As for its food-safe credentials; well, it is food, or at least a very common cooking ingredient. Apply the oil evenly over the entire surface of the product, and for the glossiest result, buff it off with a cloth after a few minutes. Make sure the wood’s clean before you try this, though. 

However, this simple solution isn’t quite as conclusive as you might hope for. For one thing, vegetable oil can easily stain wood, penetrating porous timbers, leaving permanent, nasty stains, and a greasy sheen. It can also attract dirt and dust particles, meaning that, if too may get trapped inside the coating, you might have to wipe it off and begin again. If you prefer your wood a lighter colour, you also might have to continually remove it and re-apply it, as it can darken the colour of lighter timbers over time.

French Polish

Qualities:

  1. Beautiful, signature sheen, that brings out the quality of the wood-grain like few other products;
  2. Entirely non-toxic and food-safe;
  3. Naturally durable, and resistant to abrasion and wear;
  4. After application, relatively low-maintenance in terms of additional polishing;
  5. Doesn’t yellow over time;
  6. Easy to repair faulty patches.

Problems:

  1. Incredibly complicated application method, requiring multiple precise steps, specialist equipment, and very specific temperature and humidity;
  2. Very sensitive to heat and humidity; burns off with former, can grow white rings with latter;
  3. Damaged by alcohol.

French polish isn’t a product itself, but rather a process that comes about from coating wood products with shellac, a resin secreted by the female lac bug. Shellac used in this way was once the world’s dominant wood polish method, replacing natural oils and waxes and only being replaced itself by lacquer in the 1920’s. When applied properly, French polish has a significant number of benefits – most signature of all, however, is the impressive sheen it grants. It handily brings out all the beautiful intricacies of the wood’s grain and hue with an understated old-world flair and can be a very worthy investment for a statement piece of furniture such as a dining-room table. Once you’ve applied the polish, it’s very durable, doesn’t require much additional polishing, and it also resists cracking, scratches, and wear very well. As a natural resin, it’s entirely non-toxic and food-safe, and it also dries relatively quickly when the coating is done. It doesn’t yellow over time, and it’s also easy to patch up weak spots in the coating later on. 

However, the process of that application is the real downside to French polish. Properly applying French polish to any given wood product might take days (depending upon the size), requires specialist equipment, contains over a dozen complicated steps with precise requirements, and is also incredibly temperamental. While some polishes require decent ventilation to dry properly, French polish demands entirely neutral humidity and room-temperature conditions. Forget about applying it on any day (or in any environment) that comes with the risk of heat, rain, or high humidity. Shellac’s suitability for food-related matters (such as kitchen tables) is also reduced by it burning off in the presence of high heat (even hot plates), and it develops white rings in the presence of high humidity or liquids. It can also be damaged by alcohol, making a French-polished table a risky choice to host any sort of signature meal on.

Wax

Qualities:

  1. Number of pleasant aesthetic qualities (scent, sheen);
  2. Naturally lubricating, thus good for joinery/furniture;
  3. Very low-cost, and easy to produce and source ethically;
  4. Entirely food-safe and without toxins (even safe to eat itself).
  5. Provides better UV protection than oil.

 

Issues:

  1. Often difficult to remove if you want a different coating (needing a toxic solvent);
  2. Relatively weak, compared to other coatings;
  3. Can easily melt if room is above 21°C;
  4. Can stain items and yellow over time;
  5. Needs to be re-applied very frequently.

 

The most common type of wax used for wood finishes is beeswax. Commonly, other oils, such as mineral, linseed, walnut, or olive oil, are incorporated into the wax before use, but it can also be used on its own. Beeswax as a finish has a number of naturally beneficial properties, not least its easy production; low cost; pleasant scent and appearance; compatibility with ecological concerns (as in, it’s very easy to ensure your wax was sustainably sourced); its ability to act as a natural lubricant with joinery (in cabinets, drawers, etc); and its naturally waterproof nature (so long as it’s well-maintained). When applied, a wax coating also protects wood against UV radiation better than oil does. In addition to all of these, beeswax’s entirely natural composition makes it incredibly food-safe. It’s non-toxic, food-grade, and utterly safe for human consumption. Incorporating other oils also isn’t a problem, so long as you make sure they’re food-safe as well. 

This non-toxic nature has made beeswax a very popular finish for wood products that are expected to be in consistent contact with food, such as chopping boards, salad bowls and tongs. It’s also very pet-safe, making it ideal if you’re worried about your pets ingesting or inhaling a finish. 

However, beeswax has some issues. For instance, it’s very difficult to remove if you want to apply a different coating, and it needs a solvent (which can be toxic) to be removed completely. In terms of protection, it’s relatively weak compared to other coatings, and can be uniquely vulnerable to heat damage. If the ambient temperature of your room gets above 21°C, the wax can start melting and dripping, making it unsuitable for products in rooms with fireplaces – that dripping wax can also be a safety hazard. It can also cause staining on wood items it’s applied to, can yellow over time, and needs to be consistently re-applied. The more the item’s used, the more often you’ll need to re-apply the wax, too, which can be a problem for items like chopping boards that see heavy use, and applying that wax is a simple but very labour-intensive job. Fine dirt and grime can also become embedded in the wax surface, meaning you’ll have to clean it frequently. 

In short, beeswax is a food-safe finish that’s best for three types of products – products that will see infrequent use and can be stored somewhere cool, such as salad bowls; furniture that would benefit from a natural, glossy sheen and smoother operation that you don’t mind waxing frequently; or wooden sculptures or carvings, to bring out their natural sheen in a way that’s safe for children and pets to be around. However, you should be aware of its labour-intensiveness, its sensitivity to heat, and its relatively weak nature as a finish.

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