THE FIX: Some foods that change color are destined for the trash—moldy bread, brown lettuce. However, in chocolate’s case, discoloration isn’t always a bad thing. When chocolate is opened and left at a warmer temperature, some of the fat on the surface melts and recrystallizes, leaving behind a white substance (referred to as bloom). Unless the chocolate is far beyond its expiration date, it’s fine to use in baking. The bloom will disappear as soon as the chocolate is melted. Or simply wipe it off with a damp paper towel. To prevent chocolate from developing bloom or losing flavor, keep it in an airtight container in a cool area or in the refrigerator, and keep an eye on the “use by” date.