What is E517?
Complete guide to understanding ammonium sulfate in your food
The Quick Answer
E517 is ammonium sulfate, a white crystalline powder used as a dough conditioner and yeast nutrient.
It’s used in food to strengthen dough, improve fermentation, and regulate acidity in baked goods and brewing.
Most people who eat bread, beer, or commercial baked goods consume trace amounts of it regularly.
📌 Quick Facts
- Category: Dough Conditioner, Yeast Nutrient & Acidity Regulator
- Found in: Bread, baked goods, pasta, beer, yeast products
- Safety: FDA-approved (GRAS), EFSA-approved, even approved for organic food
- Approved by: FDA, EFSA, JECFA
- Key Fact: No ADI needed—no safety concern at any approved use level
What Exactly Is E517?
E517 is ammonium sulfate ((NH₄)₂SO₄), a white crystalline powder with a mild salty taste.
It’s an inorganic salt that’s freely soluble in water. The compound contains 21% nitrogen and 24% sulfur—nutrients essential for yeast and plant growth.
While ammonium sulfate is primarily known as an agricultural fertilizer (its main use worldwide), food-grade E517 serves critical functions in baking and brewing. It provides nutrients for yeast metabolism and strengthens dough structure through gluten interaction.
In technical terms, it’s a sulfate salt of ammonia used as a dough conditioner, yeast nutrient, and acidity regulator. Importantly, it’s approved even for organic food certification—among the safest additives available.
Where You’ll Find E517
E517 appears in many common baked goods and fermented foods:
– Bread and baked goods
– Crackers and flat-baked goods
– Cereal flours
– Pasta and noodles
– Beer and brewing products
– Yeast products
– Protein products
– Commercial baking mixes
If you eat bread regularly—especially commercial bread—you’ve likely consumed ammonium sulfate. It’s one of the most common food additives in commercial baking, though consumers rarely notice it due to its neutral taste and small quantities used.
How E517 Works in Baking
E517 serves two critical functions in bread-making and baking.
First, as a dough conditioner: Ammonium sulfate interacts with gluten proteins, strengthening the gluten network. This makes dough more elastic, easier to handle, and more stable during fermentation. Stronger gluten results in better bread structure, volume, and crumb texture.
Second, as a yeast nutrient: Yeast requires nitrogen and sulfur to grow and multiply. E517 provides both elements (21% nitrogen, 24% sulfur), feeding yeast cells and supporting efficient fermentation. Better fermentation means better flavor development, better rise, and more consistent results.
In brewing, E517 performs the same yeast-feeding function, supporting efficient fermentation and alcohol production.
Why Do Food Companies Use E517?
E517 solves real technical problems in baking and brewing.
Without proper dough conditioning, bread may be weak, dense, or inconsistent. Without adequate yeast nutrients, fermentation may be sluggish or incomplete, resulting in poor flavor and texture.
E517 addresses both challenges simultaneously. It strengthens dough structure while feeding yeast, making bread production more reliable and consistent. For commercial bakeries, consistency is critical—customers expect every loaf to be identical.
Additionally, it acts as an acidity regulator, maintaining optimal pH for yeast activity and dough development.
Is It Safe?
Regulatory authorities confirm E517 is safe at approved use levels.
The FDA classifies it as “Generally Recognized As Safe” (GRAS). The EFSA’s comprehensive 2019 re-evaluation specifically concluded that “sulphuric acid and its salts (E513-E517) do not raise a safety concern at the reported uses and use levels” and that “there is no need for a numerical acceptable daily intake (ADI).”
Most remarkably, E517 is approved even for organic food—the highest food safety certification available. This indicates regulatory confidence that it poses no identified health risk.
✓ Safety Confirmed: The EFSA’s 2019 assessment found ammonium sulfate “far below” the dose (300 mg/kg) that would cause laxative effects. At normal food use levels, no safety concern exists.
The EFSA’s 2019 Safety Assessment
The European Food Safety Authority’s comprehensive 2019 re-evaluation is highly reassuring.
Key findings:
– Ammonium sulfate and related sulfate salts are of low acute toxicity
– No concern with genotoxicity (genetic damage)
– No concern with carcinogenicity (cancer)
– No ADI needed because no safety concern exists at food use levels
– Mean exposure: 0.4 mg/kg bw per day (infants) to 35 mg/kg bw per day (toddlers)
– 95th percentile exposure: 3-68 mg/kg bw per day
– Critical finding: Actual exposure is “far below the 300 mg/kg dose that induced laxative effects in humans”
In plain language: the amount of ammonium sulfate people eat from food is so small that it would have to increase hundreds of times before any adverse effect could occur.
Why No ADI Was Established
The absence of an Acceptable Daily Intake (ADI) is positive—it indicates safety.
EFSA stated explicitly that “there is no need for a numerical acceptable daily intake (ADI).” This doesn’t mean safety is uncertain. Rather, it means the evidence is so clearly in favor of safety that regulators determined no specific upper limit needs to be set.
E517 is one of the safest food additives from this perspective—so safe that unrestricted use (up to needed functional amounts) doesn’t pose health concerns.
Approval for Organic Food
E517 is approved for organic food certification—a distinction few additives achieve.
Organic certification standards are the most stringent in food regulation. Only additives with excellent safety records and minimal processing concerns are approved. That E517 has this status demonstrates regulatory confidence in its safety and compatibility with organic principles.
Agricultural Use Provides Safety Data
Ammonium sulfate’s primary use as fertilizer provides additional safety confidence.
Billions of kilograms of ammonium sulfate are applied to soil annually, where it’s absorbed by plants and consumed by animals and humans. This widespread agricultural use provides real-world safety data across diverse populations and climates. Decades of agricultural use without documented harm supports the safety assessment.
Yeast Nutrient Function
E517’s role as a yeast nutrient reflects its biological compatibility.
Yeast requires nitrogen and sulfur to grow. That ammonium sulfate provides these nutrients shows it’s not a foreign chemical to biological systems—it’s a source of essential elements. Microorganisms naturally metabolize it into constituent parts.
Manufacturing and Properties
E517 is synthetically produced but chemically simple.
Ammonium sulfate is created through straightforward chemical synthesis. While synthetic, it’s not complex or novel—it’s been used in agriculture for over a century. Food-grade E517 must meet strict purity standards, ensuring it contains no harmful contaminants.
Comparison with Other Additives
E517 is part of the sulfate acid and salt family:
– E513: Sulfuric acid
– E514: Sodium sulfate
– E515: Potassium sulfates
– E516: Calcium sulfate
– E517: Ammonium sulfate
All five were evaluated together in EFSA’s 2019 assessment, and all received clean safety bills. E517 is the most commonly used in baking and brewing among this family.
Vegan, Vegetarian, and Allergen Status
E517 is suitable for:
– Vegan diets ✓
– Vegetarian diets ✓
– Gluten-free diets ✓
– Organic diets ✓
Ammonium sulfate is a chemical compound with no animal products or byproducts involved in its production.
The Bottom Line
E517 (ammonium sulfate) is a well-established food additive used as a dough conditioner and yeast nutrient in baking and brewing.
Regulatory authorities worldwide classify it as safe, with the EFSA specifically finding “no safety concern at reported uses and use levels.”
The FDA approves it as GRAS (Generally Recognized As Safe).
Remarkably, it’s approved even for organic food—reflecting the highest level of regulatory confidence.
At normal food use levels, exposure is far below amounts that would cause any documented health effect.
Its primary use as an agricultural fertilizer (billions of kilograms annually) provides real-world evidence of safety across diverse populations.
Most bread you eat contains ammonium sulfate, and decades of consumption have produced no documented health concerns.
As always, food labels must declare E517 when used, enabling informed consumer choice.