Calcium hydroxide is used to make an indigo or woad vat more alkaline. It is a fine white powder and is also known as pickling lime, builders lime, hydrated lime, or in Mexican markets, cal, where it is used to soak dried corn kernels in preparation for making masa dough. This is used in Michel Garcia’s 1-2-3 vat recipe, which we describe in our blog. It is a mild alkali and easier to use than lye or caustic soda.
We provide a food grade quality calcium hydroxide. Please wear a mask when using it as it is very fine and can be an irritating dust.