[aigel]

A lot of cooks do both - add pepper in the beginning and then again shortly before serving to get the best of both worlds (good penetration of the spice into the food and the more volatile flavors). One guy I remember doing this is Paul Prudhomme in "Louisiana Kitchen". I also do not think pepper becomes bitter by cooking. I use whole peppercorns in some soups and roasts (crock pot). When you eat one of these corns after they are boiled for 8 hours, they do not taste bitter.

G