A water-soluble, nontoxic chemical compound often used in pickling and preserving. Available at grocery stores.
A double sulfate of aluminum and potassium or aluminum and ammonia; used as an astringent and styptic.
Alum, a compound of aluminum and potassium, forms a double sulphate salt that possesses a potent astringent impact. The salt manifests in the form of opalescent white crystals, which are somewhat shiny and typically measure less than half an inch in length. This compound is occasionally employed to produce pickles that are firm and crunchy.
Potassium aluminum sulfate, when mixed at a ratio of one teaspoonful to a pint of water, creates an astringent solution commonly applied to desiccate and toughen the skin on sweaty feet. Alum is also employed as a vaginal douche for specific medical situations and is found in the formulation of numerous commercial antiperspirant lotions.