Calcium Hydroxide

Calcium hydroxide, also called pickling lime or hydrated lime, is used in both natural indigo extraction from plants and in certain indigo dye vats for raising the alkalinity (increasing pH). This calcium hydroxide is sold as a powder and is an important component in both the ferrous (iron)-lime indigo vat and the fructose (1-2-3) indigo vat. 

For indigo fermentation vats we usually use soda ash not calcium hydroxide to make the solution alkaline. 

1 pound of powder or 200g of powder (for indigo ferrous vat 5-15 gallons)