Here it goes: You purchase a cup of coffee at Dunkin Donuts. The coffee is about 90deg. in a styrofoam insulated cup. The main question is: Should you mix your cream, which is about 5deg cels, in the coffee at dunkin donuts or wait til you get home? The temperature outside is about 25deg. Home is about 5-10min away by car. It's not a trick question. Ok it should be that you mix the cream before, but why?