Calcium hydroxide is a common base used when making indigo vats. It will reduce oxygen in an indigo or woad vat and make it more alkaline. It is a fine white powder that is also known as pickling lime, builders lime, hydrated lime, slaked lime, calx and aragonite. A pinch or two added to dye-bath will enhance or even change some colors, especially woods. Neutralizes acids without creating the opposite alkaline solution.
Whisking your indigo vat, the lime will very quickly absorb the carbonic acid of the air (CO2) and be neutralized. The lime will then be transformed into calcium carbonate (chalk or limestone) a non-toxic substance which can be poured down domestic drains. Both liquid and sediment of these vats may be used as compost.
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.