Alum

Alum is a versatile pantry staple often found between gourmet salts and other fine seasonings. Recognizable by its white, crystalline appearance, it features a very strong astringent taste, thus used sparingly in cooking. Despite its powerful taste, alum is best known for its crispness enhancing properties; it's the secret ingredient used in pickling recipes to maintain the crunchiness of cucumbers and other pickled vegetables. Outside of kitchen use, it's also known for its hygiene and health-promoting features, making this common, yet versatile pantry item an interesting addition to your grocery list.