Bakers Ammonia

According to the Dictionary of American Food & Drink by John F. Mariani:

"Hartshorn - A source of ammonia used in baking cookes or, as "salt of hartshorn," as smelling salts. Once the word meant literally the ground horn of a hart's (male deer's) antlers, but ammonium carbonate was later used as a substitute, which also went by the name of "salt of hartshorn."

Ammonium carbonate is the commercial salt, formerly known as sal volatile or salt of hartshorn. Ammonium carbonate is used when crushed as a smelling salt. It can be crushed when needed in order to revive someone who has fainted. It is also known as "baker's ammonia" and was a forerunner to the more modern leavening agents baking soda and baking powder.

Ammonium carbonate was historically obtained by the dry distillation of nitrogenous organic matter such as hair, horn, decomposed urine, etc.[citation needed]

Currently, it is produced by heating a mixture of ammonium chloride, or ammonium sulfate and chalk, to redness in iron retorts, the vapors being condensed in leaden receivers.[citation needed] The crude product is refined by sublimation, when it is obtained as a white fibrous mass, which consists of a mixture of ammonium bicarbonate, NH4HCO3, and ammonium carbonate, NH2COONH4, in molecular proportions; on account of its possessing this constitution it is sometimes called ammonium polycarbonate. It possesses a strong ammonium smell, and on digestion with alcohol the carbonate is dissolved and a residue of ammonium bicarbonate is left; a similar decomposition taking place when the polycarbonate is exposed to air.

Ammonia gas passed into a strong aqueous solution of the polycarbonate converts it into normal ammonium carbonate, (NH4)2CO3, which can be obtained in the crystalline condition from a solution prepared at about 30 °C. This compound on exposure to air gives off ammonia and passes back to ammonium bicarbonate. It has pH of 9.

Baker's Ammonia is a leavening ingredient called for in many old world recipes, especially those from Scandinavia. It is also called "hartshorn".

Unlike baking powder or soda, Baker's Ammonia (ammonium carbonate) leaves no unpleasant alkaline off-flavor in baked goods. It is used for cookies, crackers and cream puff-type pastries, items which are small, thin or porous. It is not used for cakes or other large items because the ammonia gas cannot evaporate from these items. You will notice an odor of ammonia while baking, but this will quickly dissipate and the baked product will not have an odor or taste of ammonia.

Because Baker's Ammonia has a tendency to evaporate when exposed to air, it should be stored in a jar with a tight cover. It will not spoil, but will "disappear" if not stored properly.

BAKER'S AMMONIA (AMMONIUM CARBONATE): Don't confuse this with ordinary household ammonia, which is poisonous. A type of baking powder, it yields a very light, airy product, but can impart an ammonia flavor to baked goods. It's best used in cookies, which are flat enough to allow all of the ammonia odor to dissipate during cooking. Northern Europeans still use it because it makes their springerle and gingerbread cookies very light and crisp. It comes either as lumps or powder. If it isn't powdered, crush it into a very fine powder with a mortar & pestle or a rolling pin.

Uses

As well as in smelling salts, ammonium carbonate is still used as a leavening agent in particular recipes, particular northern European and Scandinavian. It can sometimes be substituted with baking powder, but the finished product will never be as airy and light as the original recipe. Icelandic loftkökur (air biscuits) for instance simply cannot be made with anything other than ammonium carbonate.

Buckleys cough syrup from Canada also uses ammonium carbonate as an active ingredient intended to help relieve symptoms of bronchitis.