How to fix a warped cutting board

November 01, 2016 9 Comments

How to fix a warped cutting board

There are some truths and a lot of myths out there about wooden cutting boards. This is part 1 in a series of 3 blog posts I’ll be releasing on the topic. I’ll take some time to debunk some popular beliefs about them and shed some light on these three topics in particular:

- How to choose a good cutting board
- How to care for your cutting board
- How to fix a warped cutting board (if you didn't follow the first two!)

It may seem a bit out of order, but I am going to start with “How to fix a warped cutting board.” I was having a conversation with some customers at a recent craft fair about the best way to flatten a warped or cupped (more common) cutting board. It became obvious that there are a lot of old wives’ tales and confusion about the best way to do so. (It reminds me of many a conversation about the proper way to wash, use and season a cast iron pan!) So, I want to take a minute to set the record straight, specifically why we suggest the “turn it over” method and why this super simple method works!

extremely warped cutting board
- this cutting board has seen better days - but could still be flattened!

So, let’s assume that you have a warped board. You do, because your board wasn't built properly, or it has not been taken care of properly. What to do? There are a lot of crazy suggestions out there. Here are a few that I heard during my recent conversation:

Iron method – put a wet towel over your board and iron the towel with a hot iron
Steam method – steam one side of your board over a pot of boiling water
Force and water method – soak the board in water, then set it under a bunch of weight until it’s dry
Grass and sun – lay your board in some wet grass and let the sun beat down on the top
Take it to a woodworker – take it to your neighborhood woodworker and have them fix it

And here is our suggestion:

Just turn it over! – turn your cupped board over so the convex side is facing up (so it is resting on the 4 corners and the middle of the board is raised off of your counter) and leave it there until it is flat.

To shed some light on why we think this is the best method, let’s think about why cutting boards cup anyways. Cutting boards cup because the moisture content on one cutting face is different than that of the other face. It is the same thing that happens when you set a kitchen sponge on the counter and one side dries out before the other - it cups. It’s what happens when mud dries faster on the top surface than on its bottom surface - it cups. It’s what happens when a wet piece of paper dries on a table - it cups. It’s what happens when you leave a piece of bread out and it dries out - it cups. It’s what happens when you leave your cutting board flat on your countertop and the top dries more than the bottom - it cups!

cupped mud
- cupping seen in nature (this is the exact same process that warps cuttingboards)

When one surface of a board, a piece of bread, a sponge, or a piece of mud dries, it shrinks. When a surface soaks up water, it expands. This is what causes things to cup. Look at this 2” thick piece of wood for example. When it was totally dry, it measured 3 7/8" across on both the top and bottom. After one night sitting in a shallow pool of water, the top still measures 3 7/8”, but the bottom now measures 4" across - and the board is visually cupped!

cuttingboard dry width
- dry wood board width - 3 7/8"

cuttingboard wet width
- wet wood board width - 4"

This visual cupping is only across 4" of board. Imagine if you did this to a cutting board that was 4 or 5 times that wide! You could almost eat cereal out of your cutting board! A side note... did you think you could eliminate cupping by buying a super thick cutting board? Think again!

The first four methods I mentioned are different ways of doing the same thing: drying or wetting one side of the cutting board in relation to the other side to get the board to flatten. These methods usually work, but can be bad for your board. Heat and moisture methods have the tendency to flatten your board in the short term, but return to their warped state after as few as 1 or 2 uses. Applying unnecessary heat or moisture to your cuttingboards causes internal stresses in the wood that can eventually cause a board to break too. I admit it, woodworkers aren't the solution to all your problems either! The “take it to a woodworker method” is only a temporary fix. Your board was flat to start with and it got warped, so having a woodworker flatten it out for you won’t solve any of your problems if you keep treating it the same way.

So, if you have a cupped cutting board, skip the iron, skip the steam, skip the grass, skip the trip to the wood shop (although that would be fun) and simply turn your board over. This will expose the wetter side to air and even out the moisture content in the board, thus flattening it out over time. This might take a few days or weeks in the worst cases, but is the gentlest and most permanent way to flatten a warped cutting board.

Here are some pictures from a recent test I ran to test the "turn it over" method. It works amazingly well!

stack of cutting boards
- Stack of 1/4" thick cutting boards fresh from the woodshop

cupped cutting boards
- the same boards after a 12 hour soak in a shallow pool of water

cutting boards wet, then dried out
- The same stack of cutting boards after drying out for about a week.

 cuttingboard soaking tray
- Hey Charlotte... No baking cookies until my experiment is done!

Those boards went all the way back to flat with no heat, no pressure, and no extra water!

When you get your board flat, then follow our best practices for keeping, washing and storing a wooden cutting board (I’ll save that for a future post).


Thanks and let me know how this method works for you in the comments!

 

...and please share if you know someone who could benefit from this info!




9 Responses

Judi
Judi

November 11, 2016

I have a large end-cut cutting board that was warped and am trying this (my daughter did not care for it as I had instructed). It may not work due to the way it was made but it seems to be straightening out. Nothing lost if it doesn’t work but well worth the try. Thanks for the honest information. I LOVE your products and plan to purchase some in the future. Beautiful work. You are a true craftsman. I know what it feels like to work with beautiful wood and finish a product. I spent many hours with my dad in his ‘shop’ and wish everybody could have this opportunity. Keep up the great work!

John
John

November 04, 2016

Wood, is a funny creature and not all wood is created equal. I make wooden ware full time and have done many “experiments” with different woods to see which stands up to every imaginable situation. There are only a few woods that stand up to water. The wood I use for my kitchen ware is virtually, unaffected by moisture. I’ve soaked my utensils in water for over a year to test them. NO HARM to the wood. Maple and cherry will warp like a rope if left in water for any extended period of time.
Like was mentioned in this blog, turn your cutting board over for the best results. One thing that will really help with your cutting boards is to, put rubber feet on the bottom so there will be plenty of air circulation. Make sure you pre drill your hole for the screw or it most likely will split and ruin your cutting board.

Dawn
Dawn

November 04, 2016

I didn’t realize you could fix that problem. Thank you for the information!…..Good to know!

Claire Reishman
Claire Reishman

November 03, 2016

I didn’t know the term “cupping” but that is also what happens to freshly made pottery plates if they are not covered to allow for even drying.

brad at earlywood
brad at earlywood

November 01, 2016

Thanks for the kind words! I hope you remember this and spread the word whenever you see a warped board in someones house!

Melody Hughes
Melody Hughes

November 01, 2016

Wow, Thanks for this information!

Susan
Susan

November 01, 2016

Very informative. Thank you.

Melissa
Melissa

November 01, 2016

Thank you! I learn so much from reading your blog!

Sande
Sande

November 01, 2016

Love reading your “posts,blogs,articles?” Very relevant, not too wordy….A very enjoyable read. :)

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