Indigo, Madder, Bran Fermentation Vat

A natural fermentation Indigo vat that uses natural Indigo, Madder and Bran to produce the fermentation of the Indigo dye.

Indigo fermentation vats have been used for centuries. All existing museum specimens dating from at least 2000 BC to 1750 were done in fermentation vats. (p. 80 JN Liles) Urine vats were mostly used for Indigo fermentation.

In the book ‘The Art and Craft of Natural Dyeing – Traditional Recipes for Modern Use’, JN Liles also describes an Indigo vat that is naturally fermented using Madder dye and Bran. The Indigo ferments slowly as sugars in the madder and bran are released and serve as an energy source for the fermentation process. (p.88) Natural Soda Ash is used to change the pH to an Alkali. Add sufficient Soda Ash (washing soda) to keep the pH at 8-9. This type of Indigo vat is much gentler on wool than other types of Indigo vats – and is much less harmful to the environment.

Indigo Madder Bran Vat – Day 1

I have adapted this Indigo vat for use in a small space. I use a large sized crock pot or slow cooker for the dye vat, and a large beaker. The dye solution is placed into the beaker and sits inside the slow cooker. This keeps the dye vat at a constant warm temperature. Care must be exercised though, to avoid the water evaporating from the slow cooker, as a lid does not fit on top of the cooker when the beaker is inside.

Madder and Bran

The madder that is used in this type of Indigo vat is spent madder, not new madder. After you have used the madder in another dyebath, the left over madder that no longer produces much colour is added to the Indigo vat. In this instance, I have used the madder liquid and poured it into the beaker. If you don’t wish to use the madder immediately, then pour out the liquid and let the madder dry for use later. Madder is an anthraquinone type of dye. Other anthraquinone dyes may also be used (such as Rhubarb roots), in this type of fermentation dye vat. Nothing is wasted.

Indigo Cakes or Powder

Indigo can be purchased as ground powder or as ‘cakes’. When the Indigo is made, it is formed and cut into dried cakes. Personally, I prefer to use the cakes as I find it is less messy. The Indigo powder is very fine and tends to fly everywhere – often into your nose.

I find that the cakes can be difficult to grind, even using a mortar and pestle. Many Indigo dyers recommend placing the Indigo into a glass jar and filling it with marbles and a bit of water. The jar is then shaken to break and dissolve the indigo.

Another method to dissolve the Indigo was also described by JN Liles. The Indigo is placed into a small mesh bag and suspended over the Indigo vat. The water solution softens the Indigo. The small mesh bag is rubbed between the fingers and slowly the Indigo is released into the dye vat.

I prefer to measure the amount of Indigo that I want to use, and place this into a small mesh bag. I place the bag into a small jar of water to soften. I rub the bag occasionally to release the softened Indigo into the water. Then I pour the Indigo liquid into the dye vat. I add a bit more water and allow this to soak and soften. I find that using this method I have better control on how much Indigo I have added to the vat each day.

It can take several days for the vat to begin to ferment.
I check the vat each day, checking the pH. I add a bit of soda ash to keep the pH at 8-9. And also add more madder and bran to keep the fermentation process going.

Please check back in a few days to see the progress on my Indigo vat. I will update this as my Indigo vat lives on.