E503 - Ammonium carbonates

At a glance

• What it is: A group of related salts, mainly ammonium carbonate and ammonium hydrogen carbonate (ammonium bicarbonate), used as leavening agents
• What it does: Produces gas in the oven to puff and crisp low‑moisture bakes like crackers and certain cookies
• Also called: Baker’s ammonia, hartshorn; includes E503(i) ammonium carbonate and E503(ii) ammonium hydrogen carbonate
• Typical labels: “Ammonium carbonate,” “Ammonium bicarbonate,” or “E503”

Why is Ammonium carbonates added to food?

Ammonium carbonates are used as leavening agents. When heated, they break down to release carbon dioxide and ammonia gases, which expand doughs and batters and create an open, crisp texture in low‑moisture baked goods.¹ A leavening agent is any substance that releases gas to lighten and aerate baked foods, a function recognized in U.S. regulations.² In the EU, ammonium carbonates are listed as E503 with set purity specifications.³

What foods contain Ammonium carbonates?

You’ll most often see them in:

• Thin, dry cookies (for example, old‑style ginger snaps, springerle, or speculaas)
• Crackers, crispbreads, and wafer sheets
• Some pastry layers and ice‑cream wafers

They are less common in cakes or muffins because moisture can trap ammonia, leaving an odor. Bakers choose them specifically for products that bake dry and thin.

What can replace Ammonium carbonates?

Possible substitutes depend on the recipe and texture you want:

• For general leavening: sodium bicarbonate (baking soda) or sodium carbonates with an appropriate acid
• Low‑sodium option: potassium hydrogen carbonate
• In baking powders: acid salts such as disodium diphosphate or monocalcium phosphate

Note: These swaps often change flavor, spread, and crispness. Baker’s ammonia is uniquely good at very dry, very crisp textures.

How is Ammonium carbonates made?

Industrial producers combine ammonia with carbon dioxide in water to form ammonium salts, then crystallize and dry the product. The commercial ingredient sold as “ammonium carbonates” is typically a defined mixture of ammonium carbonate and ammonium hydrogen carbonate that meets food‑grade purity specifications in the EU.³

Is Ammonium carbonates safe to eat?

When used as intended in baking, ammonium carbonates decompose during heating to carbon dioxide, water, and ammonia; in dry, thin products, the ammonia evaporates and does not remain in the food in notable amounts.¹ The EU sets identity and purity criteria for E503, which manufacturers must meet.³

Does Ammonium carbonates have any benefits?

• Crispness and snap: Delivers ultra‑crisp textures that are hard to match with other leaveners
• Clean taste in dry bakes: Leaves little to no salty or soapy aftertaste
• Sodium‑free: Does not add sodium, which can be useful when formulating low‑sodium baked goods

Who should avoid Ammonium carbonates?

• People sensitive to strong odors may dislike the ammonia smell during baking; good ventilation helps.
• If you are advised to follow specific dietary restrictions by a healthcare professional (for example, for kidney or liver conditions), ask your clinician about ammonium‑based ingredients in your diet.

Myths & facts

• Myth: “It’s the same as baking soda.” Fact: Baking soda is sodium bicarbonate; E503 is ammonium‑based. They behave differently and produce different textures.
• Myth: “It always leaves an ammonia taste.” Fact: In thin, dry bakes, the gases dissipate during baking, so no ammonia taste remains.
• Myth: “It’s a preservative.” Fact: Its main role is leavening, not preservation.

Ammonium carbonates in branded foods

On ingredient lists you may see “ammonium carbonate,” “ammonium bicarbonate,” “baker’s ammonia,” or “E503.” They show up most in dry cookies, crackers, and wafer products made in Europe and elsewhere. U.S. labels usually use the chemical names rather than E‑numbers.

References

Footnotes

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

2. 21 CFR 170.3 — Food additive functional use definitions (Leavening agents). https://www.ecfr.gov/current/title-21/section-170.3 ↩

3. Commission Regulation (EU) No 231/2012 — EU specifications for food additives. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩² ↩³