Building a natural indigo vat

The indigo vat is not a recipe. It’s a relationship. You build it, feed it, watch it, and learn to read its surface. A healthy vat has a coppery sheen on top, sometimes called the “flower.”

I use a 1-2-3 vat: one part indigo, two parts calcium hydroxide, three parts fructose. The chemistry is simple but the patience required is not.