Sodium bicarbonate, commonly known as baking soda or bicarbonate of soda, is a white solid salt that is crystalline, but often appears as a fine powder. Bicarbonate of soda, or baking soda, is an alkali which is used to raise soda breads and full-flavoured cakes such as gingerbread, fruit cake, chocolate cake and carrot cake. It needs an acid (as well as moisture) to activate it so is often combined with cream of tartar, yogurt, buttermilk or milk. Bicarbonate of soda gives off carbon dioxide, which expands in a mixture. Once the mixture is cooked, the carbon dioxide is replaced by air, leaving a light cake or bread.
