Let us start with cocoa. Cocoa is the dry chocolate powder derived from chocolate liquor. It comes in two types: natural and Dutch process. Dutch processed cocoa is processed with an alkaline. It is slightly darker, smoother, and more easily dissolved than natural cocoa.
Bitter (unsweetened) baking chocolate is made from pure chocolate liquor. By specification, it must contain 50 to 58 percent cocoa butter though with inferior products, vegetable oil may he added.
Milk chocolate is made with ten percent chocolate liquor. It contains a minimum of twelve percent milk solids. Because it has such a low percentage of chocolate liquor, rarely is it melted and added to batter or dough.