What is E503?
Ammonium carbonate — the old-fashioned "baker's ammonia" raising agent behind extra-crisp gingerbread and speculaas, which fully bakes away rather than staying in the finished biscuit.
E503 covers two closely related raising agents, ammonium carbonate (503i) and ammonium hydrogen carbonate, also called ammonium bicarbonate (503ii). Both were traditionally known as "baker's ammonia" or hartshorn salt, and both decompose completely into carbon dioxide, ammonia gas and water during baking, which is exactly what makes thin, crisp biscuits like gingerbread and speculaas so light and crunchy. It's permitted in Australia, the EU and the US, and JECFA hasn't set a numerical Acceptable Daily Intake because the breakdown products are compounds the body already handles routinely. Goodnessly rates it Safe.
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Read the FAQ →
What is ammonium carbonate?
E503 is a shared code for two related ammonium salts used as raising agents: ammonium carbonate and ammonium hydrogen carbonate (ammonium bicarbonate). Historically called "baker's ammonia" or hartshorn salt (once made from deer antlers, now produced synthetically), it works differently to baking soda or baking powder. When heated, it breaks down entirely into carbon dioxide gas, ammonia gas and water, with no solid residue left behind — provided the baked good is thin enough for the ammonia smell to fully escape during baking. That's why it's reserved for thin, crisp products rather than thick cakes, which would trap the ammonia and leave an off taste.
What's it used for?
- Raising agent in thin, crisp biscuits and cookies
- Traditional leavening in gingerbread and speculaas/spekulatius
- Acidity regulator in some baked goods
Where you'll find E503 on the shelf
Look for it in traditional European-style baking where a very crisp, light texture matters.
Is ammonium carbonate safe? What the research says
Ammonium carbonate and ammonium hydrogen carbonate have a long, uncontroversial history in baking, and current regulatory treatment reflects that.
| Region | Status | What this means |
|---|---|---|
| AU/NZ Australia & New Zealand (FSANZ) | Permitted | Permitted as a raising agent and acidity regulator; must be declared by name or number on the ingredient list. |
| EU European Union (EFSA) | Permitted, no ADI | Listed as E503(i) and E503(ii), permitted at quantum satis (as much as needed for the intended technological purpose) as a raising agent and acidity regulator. |
| US United States (FDA) | GRAS | Generally Recognized As Safe for use as a leavening agent (ammonium bicarbonate and ammonium carbonate are separately listed). |
JECFA has evaluated ammonium carbonate and ammonium hydrogen carbonate and allocated "ADI not specified," its category for substances of very low toxicological concern at the levels used in food. This reflects that the breakdown products — carbon dioxide, ammonia and water — are compounds the body already produces and processes routinely, and that any excess use is naturally self-limiting because it leaves a strong, unpleasant ammonia taste and smell.
- Long, stable safety record: E503 has been used in baking for centuries (originally as hartshorn salt) with no significant safety controversy, and modern regulatory re-evaluations have not raised new concerns.
- Preferred for a specific texture: unlike sodium bicarbonate or baking powder, none of E503's breakdown products remain in the finished product, which is why it's still specifically preferred for very crisp, thin baked goods like traditional gingerbread and speculaas rather than being replaced by more common leavening agents.
- Self-limiting by taste: using too much produces an unmistakable ammonia smell and flavour, so there's a strong built-in incentive for bakers to use it correctly rather than in excess.
This section is checked periodically rather than continuously — if you're reading this well after the date above, it's worth confirming nothing has changed before citing it.
Who might want to limit or avoid it
- There's no specific population group regulators flag as needing to limit E503 at typical dietary levels
- Very sensitive individuals occasionally notice a faint ammonia aftertaste in freshly baked products if slightly over-used, though this is a quality issue rather than a safety one
Goodnessly rates E503 Safe. It's a long-established, low-toxicity raising agent that fully decomposes during baking, and regulators worldwide have not identified a safety concern warranting a numerical intake limit.
How to spot it on a label
E503 must be declared clearly. Look out for:
- Ammonium carbonate
- Ammonium bicarbonate / ammonium hydrogen carbonate
- 503, E503, 503(i) or 503(ii)
- "Baker's ammonia" (older or traditional naming)
It's most recognisable in imported or traditionally made gingerbread, speculaas and other very crisp European-style biscuits.
Related additives
Frequently asked questions
What is ammonium carbonate used for?
It's a traditional raising agent used in thin, crisp baked goods like gingerbread, speculaas and some crackers. When heated it breaks down completely into carbon dioxide, ammonia gas and water, which is what gives these products their light, crisp texture.
Is ammonium carbonate the same as baking soda?
No. Baking soda (sodium bicarbonate) leaves a mineral residue behind after reacting, while ammonium carbonate and ammonium hydrogen carbonate decompose entirely into gases and water with nothing left in the finished product, which is why they're specifically chosen for extra-crisp traditional biscuits.
Why does E503 need to be used only in thin baked goods?
The ammonia gas it releases needs to fully escape during baking. In a thin biscuit that happens easily, but in a thick cake the ammonia can get trapped and leave an unpleasant smell and taste, so bakers reserve E503 for thin, crisp products.
Does Goodnessly rate E503 as safe, caution or avoid?
Goodnessly rates E503 (Ammonium Carbonate) as Safe. It's a long-established raising agent that fully decomposes during baking, and regulators have not identified a safety concern requiring a numerical intake limit.
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