E511 - Magnesium chloride

At a glance

• Also called E511; used as a stabiliser and coagulant
• Common in tofu (nigari), some canned or jarred foods, and electrolyte waters
• Allowed in the EU and listed by the U.S. FDA as permitted for use in foods
• Usually added in small amounts that do not change flavor much
• Can supply dietary magnesium, though typical levels in foods are modest
• People with kidney disease or on magnesium-restricted diets should be cautious

Why is magnesium chloride added to food?

Magnesium chloride helps proteins come together and set. That is why it is widely used to coagulate soy milk into tofu (often sold as “nigari”). It can also firm up fruits and vegetables during processing, so they hold their shape after heating. In some drinks, it supplies magnesium as an electrolyte and can slightly adjust taste and mineral balance.¹²

What foods contain magnesium chloride?

You are most likely to see magnesium chloride on labels for:

• Tofu and soy-based curds (nigari-set)
• Canned or jarred vegetables and fruits that need a firmer bite
• Bottled waters and sports drinks with added electrolytes
• Some pickled or brined items where texture needs support

Its use and maximum levels depend on the food category and local rules.¹³

What can replace magnesium chloride?

It depends on the job you want done:

• Tofu coagulant: calcium sulfate (traditional “gypsum” tofu), calcium chloride, or acid-set styles using glucono delta-lactone.
• Firming agent for fruits/vegetables: calcium chloride is the most common stand-in; mild acidification with citric acid can also help.
• Texture building or gel formation in other foods: hydrocolloids such as sodium alginate may be used, often with calcium salts, though the texture will differ.
• Electrolyte/mineral replacement: potassium salts such as potassium chloride are typical in salt-reduced foods and drinks.

How is magnesium chloride made?

Food-grade magnesium chloride is produced from natural brines. Manufacturers commonly obtain it by concentrating seawater or salt-lake brines and recovering the magnesium-rich fraction (often called “bittern”). It can also be made from mined minerals that contain magnesium salts. These routes yield either the hexahydrate crystals (MgCl2·6H2O) or an anhydrous form, which are then purified to food specifications.⁴¹

Is magnesium chloride safe to eat?

Regulators in the U.S. and EU allow magnesium chloride to be used in foods when good manufacturing practice is followed. In the EU it has the designation E511 with published purity criteria. The U.S. Food and Drug Administration lists magnesium chloride on its Food Additive Status List and in its inventory of substances added to food.¹²

As with other magnesium salts, very high intakes from supplements or medicines can cause diarrhea and other gastrointestinal effects. Normal food uses are much lower than those amounts.⁵

Does magnesium chloride have any benefits?

Yes. Magnesium is an essential mineral for muscle and nerve function, energy metabolism, and bone health. When magnesium chloride is used as a fortificant or electrolyte, it contributes to magnesium intake. However, in many foods it is added mainly for texture, so the amount of magnesium provided can be small.⁵

Who should avoid magnesium chloride?

• People with kidney disease or who must limit magnesium should talk to a clinician before regularly consuming magnesium-fortified foods or supplements.⁵
• Those taking certain antibiotics and other medicines should separate dosing from magnesium-containing products to avoid reduced drug absorption (a pharmacist can advise on timing).⁵

Myths & facts

• Myth: “Nigari is not an additive.” Fact: Nigari is largely magnesium chloride from seawater; on labels it may appear as magnesium chloride (E511).
• Myth: “It’s a preservative.” Fact: Magnesium chloride is used for texture and as a coagulant, not to preserve food.
• Myth: “It makes foods taste bitter.” Fact: At typical levels it has little taste impact; texture is the main reason it’s used.

Magnesium chloride in branded foods

You’ll often find magnesium chloride in:

• Tofu made with nigari (check the coagulant on the ingredient list)
• Bottled “electrolyte” waters and some sports drinks
• Certain canned or jarred produce where a firm bite is desired

Tip: Look for “magnesium chloride,” “E511,” or “nigari” on ingredient lists. Placement near other salts or coagulants is common.

References

Footnotes

1. Commission Regulation (EU) No 231/2012 — Specifications for food additives. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩² ↩³ ↩⁴

2. Food Additive Status List — U.S. FDA. https://www.fda.gov/food/food-additives-petitions/food-additive-status-list ↩ ↩²

3. Regulation (EC) No 1333/2008 on food additives — EUR-Lex. https://eur-lex.europa.eu/eli/reg/2008/1333/oj ↩

4. Magnesium Compounds — USGS, National Minerals Information Center. https://www.usgs.gov/centers/national-minerals-information-center/magnesium-compounds-statistics-and-information ↩

5. Magnesium — Fact Sheet for Health Professionals — NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/ ↩ ↩² ↩³ ↩⁴