I taught a cooking class a couple of weeks ago at an Art Institute and we were demonstrating hand dipped truffles. We had the folks designing there own transfer sheets with colored cocoa butter. It was a hands-on class and none of the students had any chocolate experience. Last night, one of the students had mentioned that the ganache that we used as the base for the truffles had become grainy over time. It was smooth at the time of the class and to the best of my knowledge the truffles were all completely enrobed in chocolate. It was a cold night here in the midwest. Could this have had something to do with the change in the texture of the ganache over time? Thanks