Angel food cake is a light sponge cake made with egg whites but no yolks or fats. The cake relies on air beaten into the egg whites (usually 10 to 12) to make it rise. Traditionally, it is baked in an angel cake tin or ring mould as this allows the cake to cook evenly. In contrast to the delicate colour and texture of angel food cake is devil’s food cake—a dense, rich chocolate cake. Bicarbonate of soda is used in the cake mixture, causing the chocolate to turn a deep red–brown colour.