A chemical leavening agent made historically by heating the ground antlers of a hart, or male deer, to produce ammonium carbonate. It is also called baker's ammonia today. When heated, it releases ammonia, carbon dioxide, and water vapor, giving baked goods a light, crisp texture without the alkaline aftertaste left by baking soda or baking powder. Because the ammonia gas needs room to escape during baking, it works best in thin, porous items such as cookies, crackers, and cream puffs, and poorly in cakes or other large baked goods. It has largely been replaced by baking soda and baking powder but still appears in some traditional Scandinavian and German holiday cookies; used in excess, it leaves an unpleasant ammonia smell and flavor.