Is it safe to use diluted lye on a butcher block cutting board?

[Henry Anderson]

I'm making an end grain cutting cutting board using both maple and cherry. I've heard that both a lye solution and potassium dichromate(not mixed..) will "speed up" cherry turning a deeper cherry color. From what I have read about potassium dichromate, I am concerned about using it. However, diluted lye might be a safe option. Does anyone have any thoughts on this"?

[Jim Riseborough]

I'm making an end grain cutting cutting board using both maple and cherry. I've heard that both a lye solution and potassium dichromate(not mixed..) will "speed up" cherry turning a deeper cherry color. From what I have read about potassium dichromate, I am concerned about using it. However, diluted lye might be a safe option. Does anyone have any thoughts on this"?

I would not do it. Lye is a caustic chemical and would not want it mixing with a board that I would prep food on.

[Joe Jensen]

UV Rays darken Cherry. Complete the project and finish sanding it and then put it where it will get sunlight. Intense sun could dry, warp, and crack to indirect is best. I've alsa ready about using UV bulbs to do it in the shop.

[Ryan Mooney]

There are two problems with Lye.

First it is a dangerous caustic as Jim notes. That part doesn't overly concern me in this use case (at least not past the normal "handling lye" concerns) as its a relatively easy problem to solve. First use proper PPE and handling when working with Lye (make sure you mix in the right order to avoid getting boiling lye splashed into your face... wear a face mask and gloves and preferably a rubber apron). Second once you're done with the coloring you can neutralize any residual lye with a simple dilute white vinegar wash. And before anyone says you can't use lye in food, I've made both century eggs (not really recommended but it was .. interesting..) http://www.instructables.com/id/century-eggs/ which are aged in lye, and traditional pretzels which are boiled in a dilute lye bath before baking (that's what makes the really awesome crust) - both of which are fairly well established food prep practices (for some values of "well established" ).

Second, and perhaps more concerning is that industrial lye may not be 100% pure and can include various heavy metals, etc.. So if you do go this route, don't use drain cleaner but spring for some food grade lye from a reputable source (like http://www.essentialdepot.com/catego...omponents.html), its cheap enough and there's no reason to not get the better stuff.

If you're uncomfortable with Lye, you _might_ get a similar reaction with Sodium Carbonate (aka washing soda). You can make Sodium Carbonate from baking soda (so you know its food safe) by cooking it in a glass dish in a 400F-425F oven for 1-2 hours stirring a few times along the way (it should turn kind of grainy). I don't know if its the alkali reaction that's darkening the cherry.. but if you're curious it would be a cheap/safe thing to do a small test run (you can buy washing soda in the grocery store for a couple of bucks.. personally I'd have no worry about using the grocery store version on a food prep surface - and have at my home - but offering the alternative path).

The potassium dichromate OTOH I wouldn't personally let anywhere near anything resembling food prep.

[Steve Demuth]

+1 on all of this. Lye in and of itself is not necessarily a no no. Lye is dangerous when concentrated and must be used carefully, but Lutefisk, e.g., is a Norwegian delicacy (or survival food, depending on who you ask) that is just Cod hydrolized in lye. Pure lye is sodium hydroxide. When dissolved in water, it's literally sodium ions and hydroxide ions separately in solution. Sodium is ubiquitous in food, and hydroxide ions are always present in low concentration in any water. If you use pure lye and dilute appropriately after use, or neutralize with a weak acid, you'll be safe.

But I would not use commercial, non-food-grade lye. It is non-food-grade for a reason, including potential metal and other contaminants. Food-grade sodium hydroxide is available on Amazon if you want to go ahead. Or you can simply use Alum - it'll get you the same ions and free radicals that are doing the work on the cherry, and is commonly used in food prep. Obviously you'd want to verify on a sample of your work before going whole hog, but I'd expect it to have the desired result.

And definitely don't get the Potassium Dichromate anywhere near your kitchen.

[John C Cox]

If it's for a butcher block - just oil it good and let it be. It will age out just fine.

A few days in the sun and it will be that beautiful color we all love in Cherry.

Over time - you will resurface it (cleaning up the hacked up end grain on a butcher block was what a block plane was originally used for)... And it will expose fresh wood. But it will darken soon enough...

[Lee Schierer]

If you apply mineral oil to protect the wood, it will darken you cherry a bit then age will do the rest. You'll be amazed at how quickly it darkens all on its own.

[Brice Rogers]

I have experimented using an iron/vinegar solution on oak. (1 cup of vinegar, throw in a wad of steel wool, leave it sit for a day and dab it on the oak). I turns the oak black almost immediately. I tried it on other varieties of wood and also tried various dilutions. I'm wondering if this might have some positive effect on cherry. I would have experimented myself with a piece of cherry but I don't have any of that wood laying around.

I'm guessing that vinegar and a low concentration of iron oxide isn't going to be a dangerous solution.

Has anyone ever tried this on cherry?

[Lee Schierer]

I'm guessing that vinegar and a low concentration of iron oxide isn't going to be a dangerous solution.

Has anyone ever tried this on cherry?

I've been trying to make some threshold pieces to match some flooring and looked at ebonizing (iron/vinegar). Several of the sites I check said that the solution will also turn cherry black. The solution reacts with the tannins in the wood to produce the black color.

[Steve Demuth]

You probably don't even need the vinegar, at least on oak. The tannins in Northern Red Oak in particular are more than acidic enough that a little iron in solution will turn it ebony black. Happens to the oak skirt board on my old beater bench every time I sharpen on it: water + iron + oak = black, penetrating stain.

[Ryan Mooney]

But I would not use commercial, non-food-grade lye. It is non-food-grade for a reason, including potential metal and other contaminants. Food-grade sodium hydroxide is available on Amazon if you want to go ahead. Or you can simply use Alum - it'll get you the same ions and free radicals that are doing the work on the cherry, and is commonly used in food prep. Obviously you'd want to verify on a sample of your work before going whole hog, but I'd expect it to have the desired result.

Yeah I wasn't sure which ions and/or free radicals were causing the coloration. It would be interesting to try several things and see if you could figure out what the actual reaction was. My initial guess was that it was the sodium or potassium based on the two known sets of chemicals hence the Sodium Carbonate idea as you'd get a free sodium ion there. I've used Sodium Carbonate for pretzels as well and you get a similar increase in the maillard reaction which I ?think? might be vaguely related to what's happening in the cherry.. Its not quite as effective as lye for that purpose but is more than a bit easier to work with

For alum it would be interesting to compare the Potassium and Sodium variants... I suspect that the sodium variant would work better as its a fair bit more reactive (but have been surprised in the past..).