By Jeanne Yacoubou, MS
In January 2025, a reader asked The Vegetarian Resource Group if magnesium chloride (MgCl2) “…is always vegan.” Based on previous knowledge of this ingredient and recent confirmations by several independent manufacturers, we affirm that magnesium chloride and a related substance, nigari, are both always vegan.
What Is Magnesium Chloride?
Magnesium chloride is a naturally occurring mineral salt that is commonly extracted from seawater. It may also be harvested from underground mineral deposits in seabeds. Inexpensive with a low freezing point, MgCl2 is commonly used for winter road deicing. This chemical is also antibacterial, odor-inhibiting, and hygroscopic (water-loving). These properties make it ideal for use in household cleaning and personal care products as well as in cosmetics. Magnesium chloride is also used in fertilizers and animal feed. It is sold as a powder, flakes, or liquid.
A common food use for MgCl2 is as a coagulant in tofu production. It serves this function by thickening soymilk into curds so they can be more easily pressed into a solid block. Gypsum (calcium sulfate) is the most common coagulant for tofu production and results in a soft and silky texture.
Magnesium chloride is used as the coagulant when firmer tofu is desired. Some eaters report that MgCl2 confers a bitter taste to tofu while gypsum lends sweet notes to it. Magnesium chloride acts more quickly in soymilk coagulation than gypsum, so is preferred when production time is limited.
What Is Nigari?
Nigari is a substance most commonly derived from seawater evaporation and used as a tofu coagulant. Nigari is sold as a liquid, coarse granules, or fine crystals.
Nigari is formed after the extraction of sodium chloride (NaCl) and calcium sulfate from seawater. The remaining liquid, called bittern, primarily contains magnesium chloride and other trace substances such as potassium chloride and magnesium sulfate. Nigari is the Japanese word for bittern. The bitter notes in tofu made using nigari are due to the presence of magnesium sulfate.
According to Japanese nigari producers, authentic nigari contains five parts magnesium chloride to one part sodium chloride with small quantities of other trace mineral salts. To obtain this, seawater is kettle-boiled, leaving sodium crystals on the bottom while nigari is the remaining liquid on top. Solutions consisting solely of seawater or made from magnesium chloride dissolved in water may be sold as nigari but are not authentic nigari.
Nigari produced through sun-drying seawater contains large amounts of magnesium sulfate, making the resulting product bitter. Reverse osmosis or ion exchange methods are modern techniques to produce nigari. The former yields both pure water and concentrated seawater with high amounts of sodium chloride. The latter is added back to the water, yielding very salty-tasting nigari water. Nigari made by ion exchange lacks both the bitter sulfate ions and toxic contaminants such as PCBs, dioxins, arsenic, mercury, and lead. It is the safest, most pleasant-tasting form of nigari available.
Manufacturer Confirmations on the Vegan Status of Magnesium Chloride and Nigari
The VRG asked eight manufacturers of magnesium chloride and nigari about these ingredients’ origin and processing. Here are the responses we received.
Q: Is your food grade magnesium chloride derived from or processed with animal ingredients?
From Adnan Heikal of Alliance Chemical:
A: “This product does not contain any declared animal-origin materials [or processing aids] in its composition.”
From Owen Donald of Celtic Chemicals:
A: “None of our products are derived from animal ingredients [or have] animal-derived processing aids involved in their manufacture.”
Q: Is your food grade nigari derived from or processed with animal ingredients?
From Sandra Gibson of Sea Salts of Hawaii:
A: “No, it is only deep ocean magnesium solar evaporated, not other ingredients.”
From Newfoundland Salt Company:
A: “No.”
From Ema Sogabe of Mitoku Co.:
A: “Our Nigari does not contain any animal/animal derived ingredients/processing aids. As matter of fact, we would like to confirm that there are no animal derived ingredients/processing aids at the processing site at all.”
The contents of this posting, our website and our other publications, including Vegan Journal, are not intended to provide personal medical advice. Medical advice should be obtained from a qualified health professional. We often depend on product and ingredient
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