Overview
About Ammonium bicarbonate
Ammonium bicarbonate (E503), better known to bakers as baker’s ammonia or hartshorn, is the oldest chemical leavener still in commercial use.
It is what gives springerle, speculoos, gingersnaps, koulourakia and thin crackers their dry shattering snap. Unlike baking soda it leaves nothing behind: in the oven it breaks apart entirely into ammonia gas, carbon dioxide and water vapour. On the trigger side it is close to inert, grading A on histamine, salicylate, oxalate, every FODMAP, gluten, dairy, sulfite and glutamate.
Sensitivities
How Ammonium bicarbonate scores
Watch for
What trips people up
- Nothing on the classic intolerance panel. If a cracker or biscuit sets you off, the wheat, the fructans, the fat or the flavouring are far more likely than the leavener
- The ammonia smell during baking is the reaction working, and it only clears properly in thin, dry bakes. Used in a cake or a soft bread the gas stays trapped and the finished crumb genuinely tastes of ammonia, which is a cooking fault rather than a sensitivity
- Ammonia vapour is a respiratory irritant. A large batch in a small unventilated kitchen can sting the eyes and nose, which is worth knowing if you have asthma or scent sensitivity, though the baked cookie carries none of it
- Graded C for anti-inflammatory, AIP, DASH and Mediterranean. That reflects the sweet crisp biscuits and packaged crackers it lives in rather than any property of the salt
Diet fit
Where it fits
Swap ideas
More alternatives
FAQ
Common questions about Ammonium bicarbonate
Why does baker’s ammonia make cookies crisper than baking soda?
Because it disappears completely. Ammonium bicarbonate decomposes into three gases and leaves no solid residue at all, so the dough is pushed open and then dried out with nothing left to hold moisture. Baking soda and baking powder leave sodium salts behind, which taste faintly soapy in a thin cookie and attract water back into it as it sits, softening the snap within a day. That is the whole reason a 300 year old leavener survived into industrial biscuit production.
Is the ammonia smell from baking with hartshorn dangerous?
No, but ventilate. What you are smelling is the leavener doing its job, and in a thin, low-moisture bake the ammonia escapes entirely before the cookie comes out, leaving no smell or taste in the finished product. Ammonia is an irritant at concentration, so open a window and do not lean over the oven, particularly if you are asthmatic. If the smell is still there in the cooled cookie, the dough was too thick or too wet for this leavener.
Can I substitute baking powder for ammonium bicarbonate?
You can, roughly one for one by weight, and the cookie will rise correctly. What you lose is the texture: it will be softer and it will go soft faster in the tin. If you want to build the substitute yourself, a bicarbonate plus cream of tartar plus a little starch is the same chemistry that commercial baking powder uses. For anything soft, tall or high in moisture, baking powder is actually the better choice anyway.
Is ammonium bicarbonate the same as household ammonia?
No. Cleaning ammonia is ammonium hydroxide, ammonia gas dissolved in water at a concentration that is corrosive and never food safe. Baker’s ammonia is a dry crystalline salt that only releases its ammonia when heated, and it releases all of it into the oven rather than into the food. They share a smell and nothing else.
References
Read the background
Ratings reflect the Triggerbites ingredient database and may vary with portion size and preparation.