The Date 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
— 500 g (1 pound) chopped dried dates (no pits)
— 75 g (2.5 oz) calx (calcium hydroxide) You will use more later as you adjust the vat.
Soak the dates in hot water for 30 minutes and then simmer for 30 minutes. Ensure there is always ample water covering the dates.
Blend this mixture until it is smooth.
Fill a 20 litre (5 Gallon) stainless steel vat 3/4 full with hot water.
Add half the blended date mixture to the water in the vat. Set the other half aside and cover. The second half may be used to maintain or revive 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.