My attempts to dye indigo in the past have been frustrating with none of my vats giving more than a very pale blue. I'm ready for another try.
This time I've set up miniature fermentation vats in jars to make it easier to manage them and watch the changes.
There is so much to learn and so much to get wrong. The promising coppery sheen on the vat above has gone since I took the photo a few days ago. The fermentation was too active, the pH dropped too much. I added what was needed but it's back to square one.
At least I've found a method to keep the temperature up: I fill a hot water bottle and put it with the jars in an improvised haybox (a cardboard box wrapped in old blankets). The heat lasts about half a day that way.