What is E516?
Calcium sulphate, also known as gypsum — a natural mineral used as a firming agent, and the traditional coagulant behind authentic tofu.
E516 (calcium sulphate) is a naturally occurring mineral, also known as gypsum in its raw form and used in plaster and building materials outside food. In food, it works as a firming agent and calcium fortification ingredient, and is the traditional coagulant used to make authentic tofu. Goodnessly rates it Safe.
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Read the FAQ →
What is calcium sulphate?
Calcium sulphate is a naturally occurring mineral, known as gypsum in its raw form, mined and used in construction materials like plaster and drywall outside the food industry. The food-grade version is purified for consumption, and is best known as the traditional coagulant used to make tofu — when added to soy milk, it causes the proteins to bind together and set, giving tofu its texture. It has a mild, slightly bitter mineral taste and also contributes calcium.
What's it used for?
- Coagulant in traditional tofu production
- Firming agent in canned vegetables
- Calcium fortification in bread and baked goods
- Used as a yeast nutrient in brewing and baking
Where you'll find 516 on the shelf
Most familiar as the traditional coagulant in authentic tofu.
Is calcium sulphate safe? What the research says
Calcium sulphate has a very long history of food use, particularly in traditional tofu-making, with a clean modern regulatory record.
| Region | Status | What this means |
|---|---|---|
| AU/NZ Australia & New Zealand (FSANZ) | Permitted, no limit | Permitted at quantum satis (as much as needed for the intended purpose) in most categories. |
| EU European Union (EFSA) | Permitted, no ADI | Listed as E516, with no numerical Acceptable Daily Intake needed. |
| US United States (FDA) | GRAS | Holds Generally Recognized As Safe status under 21 CFR 184.1230. |
Calcium sulphate has been used to make tofu for over a thousand years, with an exceptionally long track record of safe food use predating modern regulatory science entirely.
- No significant regulatory changes: calcium sulphate's approval status has remained stable, reflecting its exceptionally long, low-controversy safety record.
This section is checked periodically rather than continuously — if you're reading this well after the date above, it's worth confirming nothing has changed before citing it.
Who this matters to
- No population group has a specific safety-based reason to limit E516 at typical food-additive levels
Goodnessly rates E516 Safe. It's been used to make tofu for over a thousand years, with an exceptionally long track record of safe food use.
How to spot it on a label
E516 is usually declared clearly. Look out for:
- Calcium sulphate
- Gypsum
- 516 or E516
- "Firming agent (516)" in the ingredients list
Tofu is the most traditional place to find it.
Related additives
Frequently asked questions
Is calcium sulphate the same as gypsum?
Yes, chemically. Gypsum is the mineral form of calcium sulphate, used in construction materials like plaster and drywall. The food-grade version used as E516 is purified for consumption.
Why is calcium sulphate used to make tofu?
When added to soy milk, calcium sulphate causes the soy proteins to bind together and coagulate, setting into the familiar texture of tofu. It's the traditional coagulant used in authentic tofu-making, with a history spanning over a thousand years.
Does Goodnessly rate E516 as safe, caution, or avoid?
Goodnessly rates E516 (Calcium Sulphate) as Safe. It's been used to make tofu for over a thousand years, with an exceptionally long track record of safe food use.
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