How do I unwarp a cutting board?

I have a very nice wood cutting board made from various hardwoods such as walnut, mahogany, etc., that were laminated together in strips of various widths. Over the years it has become rather U-shaped (if you look down the long axis), which affects its usefulness. What is a good method to flatten this back to at least semi-normal? Logic says to soak it in water and then weight it down, but I thought I’d better check with people who might have actually tackled a similar problem.

To unwarp a board, work in summer. The traditional cure is exposure to wet grass and hot sun. Water a grassy area thoroughly, and set the board curved side up on the wet grass. As the dry side of the board absorbs moisture from the grass, the moist side – the convex side – is dried out by the sun, and the board unwarps. Unless the warp is caused by stress in the wood, the board should straighten out within a day.

When the board has straightened out, clamp it between two straight boards so that it will dry evenly. From there, oil often with neutral, food-safe oils.

That should work. After that, you could perfect it with a planer.

Here’s another method, that essentially dries it, wets it, and flattens it.

The linked info says to place the board warped side down, while Fried Dough Ho says warped side up. Does it make a difference?

They are both saying to place the concave side down (facing the damp grass).

Logically this makes sense. Think of the rounded side as being stretched and the dished side as being compressed. If you allow the dished (concave) side to absorb moisture, it will expand. The rounded side (convex) will dry further in the hot sun.

A cutting board made of laminated blocks should not have internall stresses that cause warping.

In the future take care of the cutting board by cleaning with a damp rag and then immediately drying the surfaces. Water seeping under the cutting board during use will ruin it if allowed to stay there. Also leaving a damp rag/sponge on the cutting board can cause problems.

Mind you these suggestions only work at Unwarp Factor 2. If you want it to go any faster you risk breaking the board.

I must have misread.

I’m wondering if the humidity of the PNW winter might have added to this. This board is only used for cutting bread, buttering toast, etc. It usually gets wiped with a damp sponge just to get the crumbs off. Occasionally, it gets cleaned to remove butter, jam, or the like. I dry it afterwards with a towel, but perhaps not thoroughly enough.

put it on end and let it air dry. a towel will leave moisture on it and if only one side was wetted and wiped it could warp. even if both sides are wiped if both sides don’t dry equally it might warp.

Where are my manners? Thanks, all.

Wow! It’s magic, I tells ya. Watered the lawn, laid the board down (80+ degree day), and about 4-5 hours later, it’s nearly like new. Thanks again.