After harvesting the indigo leaves, it will be dried completely under the sun in summer season.
It will take 2-3 days to dry it. It needs to pay attention to the rain because it must not be wet during the drying process.
Correct the dry leaves and pile it up in the internal space. Amount of the dry leaves will require at least 10-20 kg to promote fermentation.
Mix it up with a moderate amount of water and cover it. Then it starts to fermentate. To complete the fermentation process it needs 3 months.
During the fermentation indigo leaves create about 70 degrees of heat. It must continue to mix it up every 5-6 days. It needs to add some water if necessary. After 3 months of fermentation Indigo leaves transform to “SUKUMO” which is a kind of indigo compost.
This fermentation method had been applied also in Europe in the middle age. It was called “CUCCAGNA”.
This compost method has a good advantage. Not necessary to use chemical reductive components like Iron sulfate or Hydrosulfite. The reduction will be done by microorganisms which are a kind of bacteria. And also the duration of vat (color) could be more than one year.
The compost could be formed into a ball shape to be convenient to transport.
It be called “Ai-dama” in japanese “Woad ball” in europe.
Seed of Persicaria tinctoria (Japanese indigo “AI”)
- 1-2g of seeds about 120-150 seeds
- An insutraction for the extraction of colors