Also, you must be aware if the cocoa is Dutched (treated with an alkaline) or natural. In many baked goods, the recipe will specifically state "Dutched," "treated with alkali," or "natural." Never substitute Dutched for natural and vice versa because this will determine whether your baked good will be as flat as a hockey puck or light and fluffy. Dutched cocoa contains that alkaline that will cause the rising actions, but natural does not, so in the case you do substitute, you need to add a chemical leavener (i.e. baking soda).