The often repeated old woodworkers tale about cell walls rupturing doesn't hold water (pardon the pun). Most likely it is being confused with what happens when wood becomes case hardened because of kiln drying at too high a temperature or some other wood defect. The article that I previously referenced barely mentioned case hardening and what they said wasn't quite detailed enough to get a complete picture. However, an important point in the article is that the main goal of kiln drying isn't to speed up drying, but to get the wood into a dry stable state by hardening the lignin. Faster drying has to be tempered with understanding drying defects. As the article says, you're walking a fine line between getting a dry stable product and unstable case hardened wood. Case hardening isn't a YES or NO condition because it exists to a certain degree in all kiln dried wood. With proper drying, the effects of case hardening can be kept unnoticeable.
