Tin pans do that. I tried many different baking utensils, and hands down, my results are perfeect every time in glass pans. Mine are all Pyrex. I use them for everything, bread, casseroles, cakes, crisps, brownies, everything. If it goes in my oven, in is in Pyrex. The only exception is my big roaster (22 lbs turkeys big), it is stainless steel.