E503II - Ammonium hydrogen carbonate

At a glance

• Other names: baker’s ammonia, ammonium bicarbonate, sal volatile, salt of hartshorn
• Role: raising (leavening) agent for baked goods
• Best for: thin, dry items like cookies, crackers, and gingerbread
• Not ideal for: moist, thick bakes where the ammonia smell can linger
• EU number: E503II (the “II” identifies ammonium hydrogen carbonate)
• Related additive: ammonium carbonate

Why is Ammonium hydrogen carbonate added to food?

Bakers use ammonium hydrogen carbonate to make dough rise. When heated, it breaks down and releases gas that expands tiny air pockets in the dough, helping baked goods lift and become crisp. In the European Union (EU), it is listed as a food additive with the function of a raising agent and has set identity and purity specifications.¹

What foods contain Ammonium hydrogen carbonate?

You’ll most often find it in low-moisture baked goods. Common examples include crisp cookies, crackers, and traditional gingerbread, where the gases can escape fully during baking and leave a clean taste.² It is less common in cakes or muffins, which retain more moisture and can trap the characteristic ammonia smell.

What can replace Ammonium hydrogen carbonate?

• Baking soda: sodium bicarbonate is the go-to swap in many recipes, though it may not create the same super-crisp texture.
• Baking powder systems: combinations of sodium bicarbonate plus acids such as disodium diphosphate or monocalcium phosphate.
• Potassium-based option: potassium hydrogen carbonate for sodium-reduced formulations.
• Note: If a recipe relies on baker’s ammonia for snap and spread (e.g., some European-style cookies), testing is wise because texture can change.

How is Ammonium hydrogen carbonate made?

Industrially, it is produced by reacting ammonia with carbon dioxide in water, forming ammonium hydrogen carbonate crystals that are then purified and dried.² This simple chemistry helps keep costs low and quality consistent across batches.

Is Ammonium hydrogen carbonate safe to eat?

In the United States, the Food and Drug Administration (FDA) lists ammonium bicarbonate as GRAS (Generally Recognized as Safe) for specified uses in food.³ In the EU, ammonium hydrogen carbonate is an approved additive (E503II) with defined specifications for identity and purity under Commission Regulation (EU) No 231/2012.¹ As with any leavening agent, manufacturers use only the amount needed for the intended effect.

GRAS means experts consider the substance safe under the conditions of its intended use; it is not a blanket approval for unlimited amounts.³

Does Ammonium hydrogen carbonate have any benefits?

• Crisp texture: It’s excellent for creating very crisp, dry bakes.
• Clean finish in thin bakes: Properly baked thin products don’t retain off-flavors because gases escape in the oven.
• Simple label: The name clearly describes the compound, and in the EU it can also appear as E503II.

Who should avoid Ammonium hydrogen carbonate?

• People sensitive to strong smells may dislike the characteristic ammonia aroma during baking; this is less of an issue in finished, thin, dry products.
• For home baking in small kitchens, good ventilation is helpful when using baker’s ammonia.
• It’s not well suited to moist, thick bakes (like some cakes), where incomplete gas release can leave an aftertaste—choose other leavening systems for those.

Myths & facts

• Myth: “It’s the same as household ammonia.”
  Fact: Household ammonia is a cleaning solution; ammonium hydrogen carbonate is a solid leavening salt used in food. They are not the same product.

• Myth: “It leaves a soapy or alkaline taste.”
  Fact: In thin, dry baked goods, the gases escape during baking, leaving a clean flavor. Texture and taste issues arise mainly in moist or thick bakes.

• Myth: “It isn’t approved by regulators.”
  Fact: The FDA lists ammonium bicarbonate as GRAS for specified uses, and the EU permits E503II with defined specifications.³¹

Ammonium hydrogen carbonate in branded foods

On ingredient lists, look for “ammonium bicarbonate,” “ammonium hydrogen carbonate,” “baker’s ammonia,” or “E503”/“E503ii” (in regions that use E-numbers). You’ll most often see it in crisp cookies, crackers, and some traditional gingerbreads. If you are avoiding it, scan the label for those names and choose products that use sodium bicarbonate or baking powder acids such as disodium diphosphate or monocalcium phosphate.

References

Footnotes

1. Commission Regulation (EU) No 231/2012 — Specifications for food additives other than colours and sweeteners. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0231 ↩ ↩² ↩³

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

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