The Henna/Madder Vat
Review the instructions for indigo vats. Don’t forget to scour your cloth or yarn before dyeing.
For a vat of about 20 litres
— 75 g (2.5 oz) powdered natural indigo
— 150 g (5 oz) henna
OR 200 g (7 oz) of madder
— 75 g (2.5 oz) calx (calcium hydroxide.)
Boil the henna (or madder) for 20 minutes and filter. Set the liquid aside. Then, in order to extract the full potential of the plant, add water, boil again for 20 minutes, filter and save the liquid. Combine the two batches of liquid together. Set the mash aside and cover with water. This can be used to make another extraction to revive or adjust the vat.
Fill a 20 litre (5 gallon) stainless steel vat 3/4 full with hot water.
Add the liquid to the water in the vat.
Add the indigo to the vat. Sprinkle on the surface of the vat and stir in until well mixed.
Add half the calx (reserve the second half if you need to raise the pH). Sprinkle on the surface of the vat and stir the vat gently. Do not whip it. You do not want air in the liquid. Wait for a few minutes. Then stir again. Repeat this stirring three or four times.
Heat until the liquid reaches 50°C (120° F). You may then turn off the heat. Leave the vat covered overnight. The next day the vat will have a bronzy surface and a dark blue indigo flower. The interior of the vat will be a clear yellow green.
Follow our How to Dye With Indigo instructions.
This vat can be used until exhausted, or it can be combined with a fruit vat.
This vat takes advantage of plant material that is rich in antioxidants. These are dyes that contain flavonoïds, for example, henna, madder or osage. Remember that these materials are used as reducing agents, not as colourants. Spent dye matter that is no longer useful for dyeing is best.
If you wish to store spent matter until you are ready to make an indigo vat you must dry the dye matter first. Otherwise it will go mouldy.