The Fruit 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
— 2 kg (4.5 pounds) sweet, over-ripe fruit.
— 75 g (2.5 oz) calx (calcium hydroxide).
In a saucepan, mash the fruit well, cover with a generous amount of water and boil for 30 minutes.
Fill a 20 litre (5 gallon) stainless steel vat 3/4 full with hot water.
Filter the juice from the boiled fruit and add to the water in the vat.
Keep the mash and cover with water. You may need to reheat this later to use to adjust 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.
KNOW YOUR FRUIT
Sweet, non-acidic fruits, rich in fructose or glucose, make excellent reducing agents. Over-ripe fruits which a greengrocer would throw away are best and may be purchased quite cheaply. The waste from jam production, peels, and rotten bits are also good.
We have tested a lot of fruit. Here is what we have found: Pears work well - apples not so much. Bananas are excellent but must be peeled. Mangos and peaches work well (take out the pits) plums are not so good. Grapes work well - white varieties have less tannin in the skin. Fresh figs can also be used. Dried dates are great. Lemon and orange rinds work well because the rinds are full of pectin - orange or lemon juice does not work because it is acidic. Some sweet vegetables also work...such as sweet onions, sweet potato and beets. Remember that the purpose of the fruit (or vegetables) is to act as a reducing agent, not to provide a colourant. Fruit stones, seeds, and pits, often contain tannin that may cause uneven dyeing or marks so should be removed. In Maiwa’s studio we have found that fruits which have ripened on the vine or tree are remarkably better