Ammonium carbonate

Ammonium carbonate (or bicarbonate) was once known by the name hartshorn because it was originally produced from harts’ horns and hooves (a hart is a male deer). Today’s commercial product is a chemical, specifically the ammonium salt of carbonic acid. Ammonium carbonate is used mainly in cookies and short dough to produce a longer-lasting crisp texture; it can also be used in pâte à choux to give it an extra puff. Ammonium carbonate can be used as a substitute for baking soda and baking powder, but only in cookies or doughs with very little moisture or in pastries that are baked at a high temperature. Unlike baking soda and baking powder, ammonium carbonate must be dissolved in water before it is added to a dry product. Ammonium carbonate reacts to heat, producing water, ammonia, and dioxide gas. It has a very strong odor that completely disappears above 140°F(60°C). It must always be stored in an airtight container or it will quickly evaporate. Ammonium carbonate can be difficult to find from bakery suppliers, but can be ordered from a chemist or local laboratory.