Ammonium Bicarbonate

About This Product

Ammonium bicarbonate is the ammonium salt of carbonic acid, formula NH4HCO3, carrying CAS number 1066-33-7 and the European additive number E503(ii). It is supplied as a white crystalline powder with a faint ammonia odour. Bakers have used it for centuries under the names hartshorn and baker's ammonia, long before sodium bicarbonate became available.

It is unique among leavening agents in that it needs no acid to react with. Heated above about 60 degrees Celsius it decomposes on its own into ammonia, carbon dioxide and water vapour, all three of which are gases. Everything it produces therefore leaves the product, so unlike bicarbonate of soda it contributes no sodium and leaves no alkaline salt residue to affect flavour or colour. That is also its limitation, and it is a strict one: the ammonia must be able to escape. In a thin, low-moisture product such as a biscuit or cracker it evaporates completely during baking, but in a cake, bread or any moist product the ammonia dissolves in the retained water and produces a sharp, unmistakable off-taste.

It is used in biscuits, crackers, cookies and wafers, in flat baked goods generally, and in some traditional confectionery, where it produces a characteristically light, crisp, open texture that bicarbonate alone cannot match.

Bio Green Foods supplies food-grade ammonium bicarbonate to specification on assay, particle size, chlorides, sulphates and heavy metals.