What is E515?
Complete guide to understanding potassium sulfates in your food
The Quick Answer
E515 is potassium sulfates, available as two forms: potassium sulfate and potassium bisulfate.
It’s a white mineral powder used as an acidity regulator, anti-caking agent, and salt substitute in numerous foods.
Most people who consume processed foods, beverages, or cheese regularly consume trace amounts of it.
📌 Quick Facts
What Exactly Is E515?
E515 is potassium sulfates, a category that includes two distinct compounds:
– E515(i) – Potassium Sulfate (K₂SO₄): A white crystalline powder
– E515(ii) – Potassium Bisulfate/Potassium Hydrogen Sulfate (KHSO₄): A related compound
Both are colorless crystalline powders that are odourless, tasteless, and freely soluble in water. Food-grade E515 has extremely high purity (99.9% K₂SO₄).
Potassium sulfates can be extracted from natural mineral sources (arcanite) or synthetically produced from potassium salts and sulfuric acid. The compound is well-established in industry, with documented use dating back to the 14th century.
In technical terms, potassium sulfates are mineral salts used as acidity regulators, anti-caking agents, and stabilizers. Notably, they serve double duty as salt substitutes—providing essential potassium while replacing sodium in low-sodium formulations.
Where You’ll Find E515
E515 appears in a wide variety of common foods and beverages:
– Cheese and dairy products (ice cream, puddings, creams)
– Beer and wine
– Other alcoholic beverages
– Non-alcoholic beverages
– Powdered mixes (baking, seasoning)
– Pasta and cereal products
– Confectionery and pastry
– Processed and canned fruits/vegetables
– Meat and fish products
– Nutritional supplements
– Dietary/low-sodium products
– Sauces and condiments
– Spice blends and seasonings
If you drink beer, eat cheese, or consume powdered mixes, you’ve likely encountered E515. It’s one of the most common food additives in processed foods.
How E515 Works in Food
E515 serves multiple critical functions in food production.
As an acidity regulator: E515 adjusts pH levels in foods, maintaining optimal acidity for taste, preservation, and stability. This is particularly important in beer and wine production, where pH control is critical for fermentation and flavor development.
As an anti-caking agent: E515 keeps powdered products dry and free-flowing. Notably, it’s non-hygroscopic—meaning it doesn’t absorb moisture from the air. This makes it ideal for seasoning blends, supplement powders, and baking mixes that need to remain free-flowing.
As a stabilizer: E515 influences food consistency, achieving desired texture and firmness in dairy products and processed foods.
As a salt substitute: E515 provides potassium while replacing sodium, making it valuable in low-sodium products and dietary supplements. This dual nutritional benefit explains its use in health-conscious formulations.
As a carrier: E515 serves as a vehicle for food colorings and flavorings, ensuring even distribution in finished products.
Why Do Food Companies Use E515?
E515 solves multiple technical and nutritional challenges simultaneously.
First, it’s cost-effective and versatile—a single ingredient addresses acidity, caking, and stability issues. Second, it provides bioavailable potassium, a mineral many consumers seek while avoiding sodium. Third, it has centuries of documented safe use—records exist of its application dating to the 14th century. Fourth, it’s naturally derived (from mineral sources), appealing to manufacturers seeking “natural” ingredients.
For beer producers and cheese makers specifically, E515 is critical for pH control and proper fermentation. Without proper acidity regulators, these products cannot achieve correct flavor, stability, or shelf life.
Is It Safe?
Regulatory authorities confirm E515 is safe at approved use levels.
The FDA classifies potassium sulfates as “Generally Recognized As Safe” (GRAS). The EFSA’s comprehensive 2019 re-evaluation concluded that potassium sulfates “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).”
This approval is unqualified—no restrictions or caveats apply. E515 can be used at levels determined necessary for its functional purposes.
✓ Safety Confirmed: The EFSA’s 2019 assessment found actual exposure to potassium sulfates is “far below” the 300 mg/kg dose that would cause laxative effects. No safety concern exists at food use levels.
The EFSA’s 2019 Comprehensive Safety Assessment
The European Food Safety Authority’s thorough 2019 re-evaluation provides exceptional reassurance.
Key findings:
– Potassium sulfates 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”
The safety margin is enormous—actual consumption would need to increase hundreds of times before any adverse effect could theoretically occur.
Why No ADI Was Established
The absence of an Acceptable Daily Intake (ADI) is exceptionally positive.
EFSA explicitly stated “there is no need for a numerical acceptable daily intake (ADI).” This doesn’t mean safety is uncertain. Rather, it means evidence so clearly supports safety that regulators determined no upper limit is necessary.
E515 is among the safest food additives available from this perspective—unrestricted use (up to functional amounts) poses no health concerns.
Natural Occurrence and Biological Compatibility
E515’s safety is supported by its natural status and biological role.
Sulfate is a natural constituent of human, animal, and plant biology—present in all biological materials. Potassium is an essential mineral. Together, they form a compound that organisms naturally process and metabolize.
Potassium sulfate’s primary agricultural use (in fertilizers providing potassium and sulfur) provides real-world safety data across diverse populations consuming potassium sulfate-treated crops.
Historical Use Demonstrates Safety
E515 has over 700 years of documented history.
Known since the 14th century, potassium sulfate (called “arcanium,” “sal duplicatum,” or “arcanum duplicatum”) has been studied by major scientists including Glauber, Boyle, and Tachenius. In the 17th-18th centuries, it was even used medicinally as a diuretic and sudorific.
This extensive historical use, with no documented harm despite widespread application, provides real-world evidence of safety across centuries and cultures.
Potassium Content and Nutrition
E515 provides bioavailable potassium—an essential nutrient.
Potassium is critical for heart function, muscle contraction, and nervous system health. Many consumers seek potassium while reducing sodium intake. E515 efficiently provides both benefits—it’s a potassium source while replacing sodium in low-sodium formulations.
At normal food use levels, potassium from E515 is well-tolerated and contributes meaningfully to dietary potassium intake.
Manufacturing and Sources
E515 can be sourced from nature or manufactured—both are safe.
Natural potassium sulfate is extracted from mineral sources (arcanite is the natural mineral form; other mineral deposits include kainite, schönite, and leonite). Alternatively, it’s synthetically produced from potassium salts and sulfuric acid.
Food-grade E515 achieves high purity (99.9% K₂SO₄) and must meet strict regulatory specifications regardless of source.
The Anti-Caking Agent Advantage
A unique property makes E515 ideal for powdered products.
Unlike many anti-caking agents, E515 is non-hygroscopic—it doesn’t absorb moisture from air. This means powdered mixes, spice blends, and supplement powders containing E515 remain free-flowing and don’t clump even in humid conditions. This property is particularly valuable in food preservation and product shelf life.
Comparison with Related Additives
E515 is part of the sulfate acid and salt family:
– E513: Sulfuric acid
– E514: Sodium sulfate
– E515: Potassium sulfates (this product)
– E516: Calcium sulfate
– E517: Ammonium sulfate
All five were evaluated together in EFSA’s 2019 assessment, and all received clean safety findings. E515 is among the most commonly used in beverage production and cheese making.
Vegan, Vegetarian, and Allergen Status
E515 is suitable for:
– Vegan diets ✓
– Vegetarian diets ✓
– Gluten-free diets ✓
– Low-sodium diets ✓
Potassium sulfates are mineral compounds with no animal products or byproducts involved in production or extraction.
The Bottom Line
E515 (potassium sulfates) is a mineral additive used as an acidity regulator, anti-caking agent, and salt substitute across numerous food categories.
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).
Its primary form (potassium sulfate) is a natural mineral with over 700 years of documented history and centuries of safe use.
At normal food use levels, actual exposure is far below amounts that would cause any health effect.
Its dual role—providing potassium while functioning as an acidity regulator and anti-caking agent—makes it particularly valuable in modern food manufacturing.
As always, food labels must declare E515 when used, enabling informed consumer choice.