Chocolate is categorized by how much chocolate liquor it contains. Unsweetened, or bitter, chocolate is 100% chocolate liquor with no sugar added. Bittersweet and semisweet chocolates have cocoa butter and sugar added to the liquor but still contain at least 35% and 15% liquor, respectively. In most cases, these 2 chocolates are interchangeable in recipes. Milk chocolate, which contains at least 10% chocolate liquor and 12% milk solids, behaves differently in recipes and should not be used in place of other types of chocolate unless specified.