Off-color cherry
November 1, 2013 | 7:00 pm CDT

Q: I am getting some discoloration in cherry. We dry it, steam it, and then bend it. After bending and drying again, it is off-color. Can you help with this problem and tell us what might be happening?

A: Cherry is a unique species in that it is very sensitive to the pH of liquids that it is in contact with. Acids (pH under 7) tend to darken the wood, giving it an "aged" look without having to wait years. In fact, cherry lumber is often steamed before drying to soften and darken the color. But where cherry really gets weird is when it is exposed to caustic materials (pH greater than 7).

Most boilers have water that is treated with a caustic chemical to raise the pH to 11. When we boil water the steam is 100 percent pure water, but we sometimes have boiler water carryover, meaning that some high pH liquid makes its way into the pipes. Here's what to do: collect some of the water that is in your steamer and take it to your friendly high school chemistry teacher for a quick pH test. If the pH isn't 7, then start looking for the source of acid or caustic material.

Have something to say? Share your thoughts with us in the comments below.

Profile picture for user genewengert
About the author
Gene Wengert

Gene Wengert, “The Wood Doctor” has been training people in efficient use of wood for 45 years. He is extension specialist emeritus at the University of Wisconsin-Madison.