This is a bit of kitchen physics, Joe.

I make homemade wheat/white bread (the recipe has three cups of white flour and 1 cup of wheat) that is perfect with PB & J. It's a nice consistency, not as tough as full whole wheat. The trick is to have the peanut butter out of the fridge long enough so it doesn't tear up the bread. Like trying to spread hard butter on bread, it just doesn't work.