E517 - Ammonium sulphate

At a glance

• What it does: dough conditioner, yeast nutrient, and acidity regulator
• Where it’s found: commercial breads and buns, flour treatments, baking mixes, and some yeast foods
• How it’s made: reacting ammonia with sulfuric acid, then crystallizing and purifying
• Safety: allowed by the U.S. Food and Drug Administration (FDA) as “GRAS” when used under good manufacturing practice; the EU sets strict identity and purity rules
• Diet notes: vegan, gluten-free, and not related to sulfites or “sulfa” drugs

Why is Ammonium sulphate added to food?

Bakers add ammonium sulphate to feed yeast and condition dough. In the United States, the FDA lists it as Generally Recognized as Safe (GRAS) for use as a dough conditioner, buffer, nutrient, and yeast food when used in line with good manufacturing practice.¹ These functions help bread rise consistently and hold its shape.

What foods contain Ammonium sulphate?

You’re most likely to see ammonium sulphate in:

• Packaged sandwich breads, hamburger and hot dog buns
• Bread mixes and premixed bakery flour
• Yeast nutrients and some commercial baking improvers

Label it may appear as “ammonium sulfate,” “ammonium sulphate,” or “E517” (in the EU).

What can replace Ammonium sulphate?

Depending on the job it’s doing, bakers might use:

• Yeast nutrients and dough conditioners such as ammonium phosphate or monocalcium phosphate
• Acidity regulators like citric acid or ascorbic acid to fine‑tune dough behavior
• Leavening system components such as calcium sulphate or sodium bicarbonate, depending on the formula

How is Ammonium sulphate made?

Food‑grade ammonium sulphate is typically produced by reacting ammonia with sulfuric acid to form crystals, followed by purification and drying.² In the EU, E517 must meet identity and purity specifications set in Commission Regulation (EU) No 231/2012, which describes the required characteristics for food use.³

Is Ammonium sulphate safe to eat?

Yes—when used as intended. In the U.S., ammonium sulphate is GRAS and may be used as a dough conditioner, nutrient, and yeast food at levels consistent with good manufacturing practice.¹ In the EU, it is an approved additive (E517) with detailed specifications that food‑grade material must meet.³

Does Ammonium sulphate have any benefits?

For bakers, this additive can help:

• Support steady yeast activity for reliable rise
• Improve dough handling and oven spring
• Deliver more uniform crumb structure and loaf volume

These are technological effects rather than nutritional benefits.

Who should avoid Ammonium sulphate?

There is no general requirement for healthy consumers to avoid E517. If you have a medical condition that requires special dietary restrictions, follow your healthcare provider’s advice about overall protein and nitrogen intake and read labels as needed.

Myths & facts

• “It’s a fertilizer, so it can’t be food.” Fertilizer-grade and food‑grade are not the same. Food‑grade ammonium sulphate must meet strict identity and purity specifications when used as E517.³
• “It’s the same as baking ammonia.” Not quite. “Baking ammonia” is typically ammonium carbonates, a different leavening ingredient with different properties.

Ammonium sulphate in branded foods

You may find E517 on the ingredient lists of sliced breads, rolls, and baking mixes from major supermarket brands. It tends to appear in small amounts alongside yeast, flour treatments, and other dough conditioners. To check, read the ingredient list for “ammonium sulfate,” “ammonium sulphate,” or “E517.”

References

Footnotes

1. 21 CFR 184.1143 — Ammonium sulfate (GRAS; functions and uses). U.S. Food and Drug Administration. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-184/section-184.1143 ↩ ↩²

2. Ammonium sulfate — Compound summary and preparation. PubChem, National Institutes of Health. https://pubchem.ncbi.nlm.nih.gov/compound/Ammonium-sulfate ↩

3. Commission Regulation (EU) No 231/2012 — Specifications for food additives listed in Annexes II and III (E517: ammonium sulphate). EUR-Lex. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0231 ↩ ↩² ↩³