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.
Indigo Stock Solution (also called a Starter or Mother). Indigo is dependent on a balanced blend of indigo powder, a base or alkali such as calcium hydroxide, and a reducing agent, such as fructose or henna. We have found it easier to build a vat if you mix these ingredients in a smaller container and let them react. Once the reaction is ready, then carefully add this stock solution to a container of water to create the vat.
How do I rebalance my Indigo vat?
If you use the 1-2-3 vat, you can re-balance it with calcium hydroxide and fructose. It also helps to stir up the sediment at the bottom to incorporate the undissolved indigo. With other types of vats, check the pH and add alkali and a reducing agent and wait for the vat to balance.