This powder is used to keep pickles crisp. Alum powder is added during the pickle curing process to ensure a crisp and crunchy pickle every time. Alum powder is often used to firm and crispen pickles by letting them soak in a sealed brine solution of water, vinegar, salt, spices, and alum powder for several weeks. Cucumbers should be pickled at the peak of freshness because they will become soft after a few days. Use up to 1/4 teaspoon of alum per pint of solution. Made in the USA