E503I - Ammonium carbonate

At a glance

• What it is: A leavening agent that releases gas when heated, helping doughs rise and crisp.
• Also called: Baker’s ammonia, hartshorn; E-numbers E503, E503i.
• Works best in: Thin, dry bakes such as crackers, wafers, and some cookies.
• Less ideal for: Thick, moist cakes where ammonia odor can get trapped.
• Label names: “Ammonium carbonate,” “E503,” or “E503i.”
• Dietary notes: Modern production is synthetic; typically suitable for vegetarian and vegan diets.

Why is Ammonium carbonate added to food?

It is added as a leavening agent. When heated, ammonium carbonate breaks down into gases (mainly carbon dioxide and ammonia) and water vapor. These gases expand tiny bubbles in dough, creating lift and a dry, open crumb that bakes very crisp.¹

Because the gases escape completely in thin, dry products, it leaves almost no aftertaste. This makes it a favorite for crackers, wafers, and some traditional cookies where a clean flavor and snap are important.

What foods contain Ammonium carbonate?

You’ll most often see it in:

• Crackers and crispbreads
• Wafers and ice-cream cones
• Dry, thin cookies and biscuits (for example, some gingerbread or spice cookies)
• Certain traditional European bakes where “baker’s ammonia” is part of the classic formula

It’s less common in thick or moist cakes, where ammonia can be trapped and leave an odor if the item doesn’t bake dry.

What can replace Ammonium carbonate?

• Baking soda: sodium bicarbonate is the closest everyday swap. It often needs an acid (like citric acid) to work well.
• Baking powder: A blend of sodium bicarbonate plus acid salts (such as disodium diphosphate, monocalcium phosphate, or sodium aluminium phosphate).
• Ammonium hydrogen carbonate (ammonium bicarbonate): Very similar performance; often used interchangeably in dry biscuits.

Note: These swaps can change texture or flavor. Baking soda and baking powder may leave a slight alkaline “baking soda” note and can produce a less glassy snap than ammonium carbonate in very dry bakes.

How is Ammonium carbonate made?

Modern ammonium carbonate is produced by reacting ammonia with carbon dioxide, then crystallizing and drying the product. Commercial “ammonium carbonate” may include a mixture of ammonium carbonate, ammonium hydrogen carbonate, and ammonium carbamate within defined purity limits.² In EU law, ammonium carbonates are grouped under E503, with E503(i) for ammonium carbonate and E503(ii) for ammonium hydrogen carbonate.²

Is Ammonium carbonate safe to eat?

• United States: The U.S. Food and Drug Administration (FDA) lists ammonium carbonate as Generally Recognized As Safe (GRAS) when used in accordance with good manufacturing practice (GMP). GRAS means qualified experts consider it safe under the intended conditions of use.³
• European Union: The additive is authorized as E503. The European Food Safety Authority (EFSA) has re-evaluated ammonium carbonates and found no safety concern at the levels used in foods.⁴

Ammonium carbonate decomposes during baking, and the gases escape from thin, dry products. Proper baking helps prevent any residual ammonia odor.¹

Does Ammonium carbonate have any benefits?

• Creates extra-crisp textures in dry, thin baked goods
• Provides strong, fast leavening without leaving a salty or soapy aftertaste
• Useful in low-moisture formulas where quick gas release and drying are desired

Who should avoid Ammonium carbonate?

No specific consumer groups are singled out by major regulators. If you are sensitive to ammonia fumes, avoid inhaling dust and make sure your kitchen is well ventilated when baking. In finished, properly baked thin products, noticeable ammonia odor should not remain.¹

If you have a medical condition requiring unique dietary restrictions, follow your healthcare provider’s advice.

Myths & facts

• Myth: It leaves ammonia in the food. Fact: In properly baked thin and dry products, the gases evaporate and odor does not remain.
• Myth: It’s the same as ammonium bicarbonate. Fact: E503 covers a family; E503i is ammonium carbonate, while E503ii is ammonium hydrogen carbonate.
• Myth: It isn’t allowed in the U.S. Fact: The FDA lists ammonium carbonate as GRAS when used according to GMP.³

Ammonium carbonate in branded foods

On ingredient lists, look for:

• “Ammonium carbonate”
• “Baker’s ammonia”
• E-number forms: “E503” or “E503i”

You’ll typically find it in crispy biscuits, wafers, and crackers. Many classic European-style cookies use it for their signature snap. Some labels may instead list the broader category “ammonium carbonates.”

References

Footnotes

1. Ammonium carbonate — PubChem (NIH). https://pubchem.ncbi.nlm.nih.gov/compound/Ammonium-carbonate ↩ ↩² ↩³

2. Commission Regulation (EU) No 231/2012 — Specifications for food additives (E 503 Ammonium carbonates). https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0231 ↩ ↩²

3. Food Additive Status List — U.S. FDA. https://www.fda.gov/food/food-additives-petitions/food-additive-status-list ↩ ↩²

4. Re-evaluation of ammonium carbonates (E 503) as food additives — EFSA Journal. https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2013.3415 ↩