Help! I baked Yogurt Pumpernickel bread today from Beth Hensperger's Baking Bread, Old and New Traditions. I followed the instructions to the letter. The bread seemed done in the recommended 45 minutes--the internal temperature was 190 degrees. The crust seemed hard and brown, as I had hoped. The loaf sounded hollow. But then, on cooling, the top softened, and the bread inside seemed to collapse, so that it was about 1 1/2 inches below the outer crust. It was very disappointing! The texture seemed fine--no ribbons of underdone bread inside. The cooled loaf had a soft top crust. Not what I was looking for!
I did open the oven very briefly after about the first 20 minutes, to throw in a sweet potato. But by that time, the top crust seemed to have set. Could this have caused my trouble?