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I’m using Minwax Pre-Stain Wood Conditioner. I’m trying to find information on whether, after drying, my surface will be safe to prepare food on.

I plan to follow up with Minwax Wood Finish (Oil based) if it’s safe for food, and probably Polyurethane, if that’s safe for food too, and assuming i actually need it.

I’ve found that the pre stain contains “modified linseed oil/hydrocarbon resin” and “mineral spirits”. I’m having trouble finding whether those are safe near food after drying.

My main concern is that the cans of stain and pre stain have lots of scary warnings about brain damage and cancer and other things, which has me on this quest to determine whether it’s safe to use on surfaces in my kitchen.

I just want to have a way to verify that they’re safe.

Does anyone know of a source that can verify that the pre stain is safe in the kitchen, after drying?

Ashlar
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Byron
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    "Does anyone know of a source that can verify that the pre stain is safe in the kitchen, after drying?" No, there isn't one. I haven't checked, but I can promise you that such a source doesn't exist. And it's no good asking the finish maker themselves, because they can't assure you (they're legally prevented from doing so) unless they have had the product tested for this in a lab. However, that doesn't mean you can't rely on this being safe... but you have to make the call yourself. – Graphus Dec 20 '20 at 08:48
  • One key bit of info you've left out here is what this is for! Kinda a big difference if you're talking chopping board, work surface, or just a shelf. Another important thing, for me at least, is what wood(s) are you working with? – Graphus Dec 20 '20 at 08:49
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    What is a pre-stained surface? A surface that has yet to be stained. Is a surface, treated with a pre-stain wood conditioner, food safe? - Is a surface that has been stained and then finished with Minwax Wood Finish (Oil based) and Polyurethane a food safe surface?- What is food safe finish for my wood counter top? – Alaska Man Dec 20 '20 at 21:41
  • According to the State of California's Prop 65 (based on the number of warning labels I've seen), it seems that everything is scary bad for you, even simple things like breathing, so take the government warnings with a smidge of salt... Don't drink your finish, but don't over blow the situation, either. – FreeMan Dec 25 '20 at 00:42

2 Answers2

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I’m using Minwax Pre-Stain Wood Conditioner. I’m trying to find information on whether, after drying, my surface will be safe to prepare food on.

I wouldn't use it. A pre-stain conditioner implies that you'll be following that with a stain of some sort, and then a finish. So to be safe, you'll need to be certain that not only this product, but also the ones that follow it are safe for food contact.

Food prep surfaces take a lot more abuse than do most other indoor woodworking projects. Cutting, scraping, scrubbing, and contact with water, detergents, acids, oils, etc. are all likely to damage any finish you're considering. Furthermore, any film-forming finish you're considering, even if food safe, will be compromised and could end up trapping pathogens. For that reason, wood surfaces meant for food preparation are generally left unfinished or treated only with a food-safe oil, such as food-grade mineral oil.

what if it’s a shelf only meant to hold equipment that comes into contact with food?

A shelf for storing equipment is a very different situation from a surface that comes in direct contact with food. In the case of a shelf, you only need to be concerned about substances transferred to the food by the equipment that was on the shelf. Most sources agree that any commercial finish is "food safe" once it has fully cured, which means that the finish won't transfer to your food just from contact. The idea is that even if the finish contains harmful chemicals, they're locked in the polymerized finish. If those chemicals won't transfer to food, they won't transfer to equipment that will later contact food. Assuming you're going to finish the shelf after the pre-stain conditioner is dry, the finish will form a barrier between the conditioner and the equipment, so the makeup of the conditioner is even less a concern.

From Fine Woodworking: According to the FDA database of approved ingredients for finishes and adhesives, all modern unpigmented finishes (ones that don’t contain lead, mercury or toxic colorants) are technically considered food safe IF they are applied in reasonable amounts and allowed to cure properly.

Bottom line: The pre-finish conditioner is probably fine to use on a shelf or even on surfaces that might come into contact with food or food prep equipment, especially if you cover it with a finish afterward. But I still think it's best to avoid using products like that on surfaces used for cutting, pounding, scrubbing, and other food preparation operations.

Caleb
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  • what if it’s a shelf only meant to hold equipment that comes into contact with food? – Byron Dec 20 '20 at 08:33
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    "For that reason, wood surfaces meant for food preparation are generally left unfinished or treated only with a food-safe oil, such as food-grade mineral oil." That is absolutely not true! The FDA specifically has guidelines on this. – Graphus Dec 20 '20 at 08:45
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    @Byron A shelf that holds equipment that comes into contact with food is not a food prep surface. You asked about making a surface safe to prepare food on, so I took you to mean that the surface would be in direct contact with food and likely used for cutting and other food prep operations. But I'll add to the answer to address that. – Caleb Dec 20 '20 at 20:07
  • @Graphus I've never seen a cutting board finished with polyurethane or other film-forming finishes, and I sure wouldn't use one. You may be interpreting to prepare food on differently than I did. – Caleb Dec 20 '20 at 20:14
  • Caleb I understand the confusion. I was having trouble thinking of how to phrase it, that I had good preparing equipment on it, so I just went with a simpler way to phrase. I figured if it were safe for direct contact with food then it would be safe for equipment. But then you brought up the point about food and cutlery, and I realized it wasn’t necessarily the same. – Byron Dec 20 '20 at 21:43
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    Should i modify my original question to include the full question? Thank you for the wonderful answer. Also, it won’t let me upvote you because I don’t have enough reputation, but I did mark as answered. – Byron Dec 20 '20 at 21:44
  • @Byron Up to you. There's no harm in editing your question to make it more clear. Sometimes when you're editing after answers exists it helps to leave the original question (so that future readers get the context) and add an update with the additional info. – Caleb Dec 20 '20 at 21:45
  • "I've never seen a cutting board finished with polyurethane or other film-forming finishes" While I have (there's actually one awaiting restoration sitting about 2' from me as I type) that's not really of import. You might have come across "salad bowl finish" in your time? Some version of that are poly (in fact they're basically versions of wiping varnish, just thinned even more than a typical wipe-on) and some woodworkers finish cutting boards in that. My personal philosophy is not to use any finish at all on cutting boards (long-grain ones, not end-grain blocks) since they don't need it. – Graphus Dec 21 '20 at 08:44
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Is a Pre-Stained Surface Food Safe?

Yes. In fact it's as safe as if you hadn't used it at all.

The reason is that pre-stain, IF you use it (see below), won't touch the food. So pretty much regardless of what it is it would be fine :-)

But the thing is that "pre-stain conditioner", "stain prep" and other similar products are usually nothing more than dilute versions of final finishes1 which would routinely be used to finish wood surfaces for use in kitchens anyway2. If they're safe for use as a topcoat/final finish they're safe to use under stain and topcoat..... where they can't possibly come into contact with the food.

Don't use pre-stain unless you need to
As covered in previous Answers, pre-stain serves basically one function: to improve the evenness of conventional staining (i.e. using a penetrating stain) on blotch-prone woods.

If you're not using a blotch-prone wood you don't need to use — and actively don't want to use — such a product because it will limit the absorption of the stain (that's how they work) meaning you won't be able to get the full colouring potential from your chosen stain.

Please note does not apply if you're using "gel stain" since this is not a penetrating stain but instead a coloured surface coating (generally, coloured jellied polyurethane).

1 The Minwax product certainly is.

2 As covered in some previous Answers, example, there's no evidence at all that a fully dried and cured wood finish is in any way a risk for direct food contact. Additionally, if needed, as referenced in the Comment I added previously, most normal wood finishes are already passed for direct food contact in FDA guidelines.

Graphus
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