Ammonium carbonate is used for leavening in cookies, flat biscuits, or crackers. In German baking, it’s known as hirschhornsalz or hartshorn, and it is also called baker’s ammonia. It is not used for cakes since the gaseous ammonia given off during baking cannot escape the thicker, higher batters and would make the baked goods smell bad. It leaves no salty or soapy taste residue as baking powder sometimes does since it completely decomposes into ammonia and carbon dioxide.
Advantages of Ammonium Carbonate in Baking
Ammonium carbonate lends a distinctive crispness and lightness to the baked good, which why it is still listed in certain recipes, despite the overwhelming use of baking powder and baking soda in modern baked goods. You can substitute baking powder for ammonium carbonate in a pinch, but the final baked product may not have the same texture. The designs on molded cookies are also said to keep their shape much better when ammonium carbonate is used.
Using Ammonium Carbonate
Usually, ammonium carbonate is mixed in with the liquid before adding to the dry ingredients, so that it dissolves well and mixes thoroughly. It must be stored dry, in a well-sealed container, because it absorbs moisture easily and clumps, To tell if it is still active, place a small amount in hot water. If it bubbles vigorously, you can use it in your recipes.