Magnesium sulfate is an inorganic salt (chemical compound) containing magnesium, sulfur and oxygen, with the formula MgSO4. It is strongly hygroscopic and often encountered as the heptahydrate sulfate mineral epsomite (MgSO4â?¢7H2O), commonly called Epsom salt.And the monohydrate, MgSO4â?¢H2O, is found as the mineral kieserite.In food preparation, magnesium sulfate is used as a brewing salt in beer production or used as a coagulant for making tofu.
