What is E516?
Complete guide to understanding calcium sulfate (gypsum) in your food
The Quick Answer
E516 is calcium sulfate, commonly known as gypsum or selenite.
It’s a white mineral powder used to firm tofu and other foods, strengthen dough, and regulate acidity.
Most people who eat tofu, bread, or canned vegetables consume trace amounts of it regularly.
📌 Quick Facts
- Category: Firming Agent, Dough Conditioner & Acidity Regulator
- Found in: Tofu, bread, baked goods, canned vegetables, cheese, plant-based products
- Safety: FDA-approved (GRAS), EFSA-approved, even approved for organic food
- Approved by: FDA, EFSA, JECFA
- Key Fact: No ADI needed—natural mineral with no safety concern identified
What Exactly Is E516?
E516 is calcium sulfate (CaSO₄), commonly known as gypsum or selenite.
It’s a white crystalline powder, odourless and slightly soluble in water. The compound exists in two forms: anhydrous (no water) and dihydrate (containing two water molecules), also called gypsum.
Calcium sulfate can be either extracted from natural gypsum mineral or synthetically produced from calcium salts and sulfuric acid. Food-grade E516 is highly purified to meet strict purity standards.
In technical terms, it’s a mineral salt used as a firming agent, stabilizer, and dough conditioner. Most famously, it’s the traditional coagulant used for centuries in Asian tofu production.
Where You’ll Find E516
E516 appears in a wide range of common foods:
– Tofu and soy products (primary historical use)
– Bread and baked goods
– Baking powders and baking mixes
– Flour products
– Canned vegetables and fruits
– Pickled vegetables
– Cheese and cheese products
– Ice cream and frozen desserts
– Plant-based meat and dairy alternatives
– Beer and brewing products
– Wine and alcoholic beverages
– Fat spreads and emulsions
– Pasta and noodles
– Cereal and breakfast products
– Sauces, condiments, and seasonings
– Nutritional supplements
If you eat tofu, bread, canned vegetables, or plant-based products, you’ve almost certainly consumed calcium sulfate. It’s one of the most widely used food additives globally.
How E516 Works in Food
E516 serves multiple critical functions in food production.
In tofu production: E516 is the traditional coagulant used for over a thousand years. When added to hot soy milk, it causes proteins to precipitate and solidify, creating tofu curd. This is the most historically documented food use of calcium sulfate.
In baking: E516 strengthens gluten networks in dough, making it more elastic and stable. It also provides nutrition for yeast, supporting efficient fermentation and better bread rise.
In canned vegetables: E516 firms vegetables during processing, preventing them from becoming mushy and maintaining appealing texture and appearance.
In cheese: E516 stabilizes and firms curds, supporting proper cheese development.
In beer and brewing: E516 controls pH and provides nutrients for yeast fermentation, ensuring efficient alcohol production and flavor development.
Why Do Food Companies Use E516?
E516 solves real technical problems in food production.
Without proper firming agents, tofu would remain liquid. Without dough conditioning, bread would be dense and weak. Without stabilizers, canned vegetables would become mushy. E516 addresses these challenges while providing bioavailable calcium—an essential nutrient.
Additionally, E516 is cost-effective, has deep historical roots (especially in Asian cuisine), and can be sourced from natural gypsum, appealing to manufacturers seeking naturally-derived ingredients.
Is It Safe?
Regulatory authorities confirm E516 is safe at approved use levels.
The FDA classifies it as “Generally Recognized As Safe” (GRAS) when used per good manufacturing practices. The EFSA’s comprehensive 2019 re-evaluation concluded that calcium sulfate and related sulfate salts “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, E516 is approved even for organic food—the highest food safety certification available. This indicates maximum regulatory confidence in its safety.
✓ Safety Confirmed: The EFSA’s 2019 assessment found actual exposure to calcium sulfate 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 Safety Assessment
The European Food Safety Authority’s comprehensive 2019 re-evaluation is highly reassuring.
Key findings:
– Calcium sulfate and 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
– Actual exposure is “far below the 300 mg/kg dose that induced laxative effects in humans”
– Previous EFSA evaluations (2003, 2004, 2008) specifically concluded calcium sulfate is “of no safety concern” as a calcium source
The EFSA noted that even in a “worst case” exposure scenario of 6g of sulfate ion from calcium sulfate, safety is assured.
Why No ADI Was Established
The absence of an Acceptable Daily Intake (ADI) is positive—it indicates exceptional safety.
EFSA stated explicitly that “there is no need for a numerical acceptable daily intake (ADI).” This doesn’t mean safety is uncertain. Rather, the evidence so clearly supports safety that regulators determined no upper limit needs to be set.
E516 is among the safest food additives from this perspective—so safe that unrestricted use (up to functional amounts) poses no health concerns.
Natural Occurrence and Biological Compatibility
Calcium sulfate’s safety is supported by its natural origins.
Sulfate is a natural constituent of human, animal, and plant biology—present in all biological materials. Calcium is an essential mineral. Together, they form a compound that organisms naturally process and metabolize.
Food-grade E516 can be extracted from natural gypsum mineral, enhancing its appeal for consumers seeking naturally-derived additives.
Approval for Organic Food
E516 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 are approved. That calcium sulfate has this status demonstrates exceptional regulatory confidence.
Historical Use Demonstrates Safety
E516 has centuries-long culinary history, particularly in Asian tofu production.
Calcium sulfate (called “gypsum” in traditional tofu making) has been used for over a thousand years in Asia. This extensive historical use, combined with modern safety approvals and no documented health incidents, provides real-world evidence of safety across diverse populations and climates.
Calcium Content and Nutrition
E516 provides bioavailable calcium—an essential nutrient.
Calcium is critical for bone health, muscle function, nerve transmission, and blood clotting. Calcium sulfate contributes bioavailable calcium to foods, making it both a functional and nutritional ingredient.
At normal food use levels, calcium from E516 is well-tolerated by most people and contributes meaningfully to dietary calcium intake.
Manufacturing and Purity
E516 can come from natural or synthetic sources—both are safe.
Natural gypsum mineral is purified and processed to create food-grade E516. Alternatively, it’s synthetically produced from calcium salts and sulfuric acid. Both sources must meet strict EU specifications for purity, ensuring food-grade material contains no harmful contaminants.
This is important: food-grade E516 is vastly different from construction-grade gypsum or plaster, which must not be confused with the food additive.
Comparison with Related Additives
E516 is part of the sulfate acid and salt family:
– E513: Sulfuric acid
– E514: Sodium sulfate
– E515: Potassium sulfates
– E516: Calcium sulfate (this product)
– E517: Ammonium sulfate
All five were evaluated together in EFSA’s 2019 assessment, and all received clean safety findings. Calcium sulfate is among the most commonly used in food production.
Vegan, Vegetarian, and Allergen Status
E516 is suitable for:
– Vegan diets ✓
– Vegetarian diets ✓
– Gluten-free diets ✓
– Organic diets ✓
Calcium sulfate is a mineral compound with no animal products or byproducts involved in its production.
The Bottom Line
E516 (calcium sulfate/gypsum) is a mineral additive used as a firming agent, stabilizer, and dough conditioner 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).
Remarkably, it’s approved even for organic food—reflecting the highest regulatory confidence.
Its primary form (gypsum) is a natural mineral with centuries-long culinary history, particularly in Asian tofu production.
At normal food use levels, actual exposure is far below amounts that would cause any health effect.
Most people eating modern foods consume it regularly without documented health concerns.
As always, food labels must declare E516 when used, enabling informed consumer choice.