Bread-Bakers v109.n046.2

My favorite daily bread loaves come out of the oven with beautiful 
color and a taut, smooth top. An hour or so later they're all 
wrinkled on top rather than staying nice and smooth. Any ideas what 
I'm doing wrong? If it matters, they're 1/4 whole wheat and otherwise 
a very standard recipe, baked at 350 convection for 35 minutes in a 
ceramic pan.

Bob
R. K. Johnson