Pickling lime

Pickling lime (Calcium hydroxide) also known as hydrated lime, or slaked lime, is an additive sometimes used in pickling. It aids in raising a pickling solution's pH level to preserve the crisp texture of the vegetables while they are stored. Pickling requires an acidic environment however, so the use of pickling lime requires care and attention. Pickling environments that are not acidic enough can become home to botulism and other potentially deadly pathogens. The potential dangers of pickling lime have pulled its use out of favor in modern pickling recipes.

If you do need to use pickling lime, only use food grade lime and be sure to wear gloves when handling it.