THE ORGANIC VAT
To make an organic indigo vat we need the same three things we need for any indigo vat :1) indigo, 2) a reducing agent and, 3) a base. We recommend natural indigo, an organic reducing agent, and a benign base.
INDIGO
We recommend natural indigo in powdered form.
A Reducing agent
To make an organic vat, use organic reducing agents. Many natural substances will behave as reducing agents. Fructose is a “reducing sugar” so it will reduce the indigo. Sucrose (white table sugar) is not a reducing sugar - it will not work. Fruits work best when they are very ripe or over-ripe. Fruits which the greengrocer is about to throw away are often perfect. Generally the less acidic the fruit the better. Other organic matter will work well, such as spent madder or henna. In the case of these dyes we are not using them as colourants but as reducing agents.
A Base
For the organic vat we recommend using the most benign base possible. This is calx (calcium hydroxide) also known as slaked lime or hydrated lime. Do not confuse it with “quick lime” (calcium oxide) which is very corrosive, or chalk (calcium carbonate) which will not work. Calx is recommended because when the vat is exhausted, whipping oxygen into the vat converts the remaining calx to calcium carbonate (chalk). Hence the exhausted vat contains only plant matter, indigo, and chalk. It makes excellent compost due to the nitrogen in the indigo.
Recipes for Organic Indigo Vats
We suggest that you take these recipes as a guidelines. Adapt them to use local materials that are plentiful and inexpensive. As with all natural dye recipes you may find yourself adjusting measures to suit your situation. We suggest that individuals do their own experiments. Clear glass pots of about one litre make excellent test vats. Try different combinations or experiment with local plants and fruits. For example, we have found mixing two organic reducing agents, such as henna and fructose, gives a strong indigo vat.
These vats give the best results if they are made the day before dyeing. See INDIGO VATS for general tips on dyeing with indigo. Remember to cover your vat when not in use.
These organic vats were originally developed by Michel Garcia, a botanist and dye chemist with a deep knowledge of how colour behaves on the molecular level. The recipes outlined here were developed by him to create efficient indigo vats using eco-friendly ingredients. Michel has been teaching and lecturing at the Maiwa Textile Symposium since 2009. He has worked with Maiwa in India as a dye specialist. Michel and Maiwa founder Charllotte Kwon meet on a regular basis to conduct natural dye research, explore recipes and test procedures. Together they are always looking for techniques that give the most exquisite colours - made to outlast the fibres they adorn.
