Natural Dyes - Indigo, The Fruit Vat

by - Thursday, August 22, 2013

The Maiwa Guide to Natural Dyes
What they are and how to use them

This post give the recipe and procedure to make an organic indigo vat. See the previous post About the Organic Indigo Vat for essential background information.

The Fruit Vat

Sweet fruits, rich in sugars, make excellent reducing agents. Over-ripe fruits which a greengrocer would throw away are best and may usually be purchased quite cheaply. The waste from jam production, peels, and rotten bits are also good.

Know your fruit
We have tested a lot of fruit. Here is what we have found: Pears work well - apples do not. Fruit stones, seeds, and pits, often contain tannin that may cause uneven dyeing or marks. Bananas are excellent but must always be peeled. Mangos and peaches work well (take out the pits) plums are not good. Grapes work well - white varieties have less tannin in the skin. Fresh figs can also be used. Remember that the purpose of the fruit is to act as a reducing agent, not to provide a colourant.

In Maiwa’s studio we have found that fruit which have ripened on the vine or tree are remarkably better.

For a vat of about 15 to 20 litres
  •    50 g powdered indigo
  •    1 kg over-ripe fruit
  •    30 g lime (calx)
In a saucepan, mash the fruit a little and boil in water for a few minutes. 

Fill a stainless steel vat 3/4 full with hot water.

Filter the juice from the boiled fruits and put in the dye vat. Keep the mash. You may need it to restart or adjust the vat. If you have decided to dye with a basket, you may put all the boiled mash directly into the vat.

Add hydrated indigo to the large vat. The quantity of indigo depends on the depth of shade. But for 15 liters, 50 g will give beautiful dark blues. Add the lime (calx).

The coppery surface of a reduced indigo vat.
If you draw your finger across the top,
the trail in the sheen should not rejoin by itself.
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 three or four times. The vat will form a bronzy surface and some blue bubbles will appear. The bubbles need to become dark blue and the vat should be a yellow green. There should not be too much sediment in the body of the vat (it should have settled).

Heat until the liquid reaches 120° F / 50°C. You may then turn off the heat. Dip the fabric or yarn you intend to dye. Immerse for 15-30 minutes (up to 60 minutes for wool). 

Rinse in cool water. This will expose the indigo to the oxygen that is in the water while also removing particles of dye matter.

The blue flower on top of the vat.
For a reduced vat it should be a deep navy blue - not a lighter cobalt shade.

A reduced indigo vat.
Note the green tinge to the body of the vat.

Hang in the air in order to oxidize the indigo. It will turn from greeny-yellow to blue. Make certain this process is complete before dipping again.

A final rinse can be done with neutral soap in water. Vinegar should be added (1/2 cup per bucket) for wool.

When you are ready to dye again, check the pH of the vat. The sugar from the fruit neutralizes the action of the lime. So if necessary, carefully add more lime – a teaspoon is suitable. Check the temperature. Reheat the vat.

The Secret of a Starter Solution

Sometimes it is easier to get your vat working in a small container and then transfer the contents of the small container to the full-size vat. The contents of the small vat is known as a “starter solution.” In a concentrated form the indigo tends to reduce more quickly and completely. Use the hot liquid from the boiled mash (in the case of fruit), all the indigo and half the lime in the starter solution. Add the remaining lime to the filled large vat. Once the starter has reduced it can be added to the big vat. The starter solution needs to be warm in order to reduce. Sometimes a starter solution can also be used to kick-start or revive a dormant vat.

Next up - three more organic vats ...
These organic vats were originally developed by French dye chemist and botanist, Michel Garcia. Michel has been teaching and lecturing at the Maiwa Textile Symposium since 2009. He has worked with Maiwa in India as a dye specialist, most notably at the 2011 Maiwa Masterclass. Michel and Maiwa founder Charllotte Kwon meet on a regular basis to conduct natural dye research, explore recipes and test procedures. Together they are always looking for techniques that give the most exquisite colours - made to outlast the fibres they adorn.

The Maiwa Guide to Natural Dyes

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  1. Thank you thank you thank you!!!!!

    Sasha McInnes
    Peru and Canada

  2. i agree with Sasha - THANK YOU THANK YOU THANK YOU!!! This is wonderful - just been struggling for so long to get supplies here in South Africa - this works like a charm! Bless you all at Maiwa - I LOVE you :)

  3. Dear Maiwa Team .I was delighted when I found your recipes. After much reading I thought I came close enough to understand the process that I could try it out .Well I think I followed all the steps for a fruit vat and have the right ingredients and it is even nice and warm where I live .I know I need a coppery surface as a sign for the reduction I just don't get it , and then when I went the next stage (just to see what happens ), no blue flower on the top, but the main body looked green .I did, put after heating it ,some fabric into it and it went from green to blue after taking it out , but there is a lot of blue discharge coming out while rinsing it .I just have the feeling its not right . So I tried another pot , pear as reducing agent and calcium hydroxide, rain water and indigo powder . left it even overnight -no coppery surface. Am not sure what to do next .ph is over 8 ( as that is as far as my ph measuring sticks go ...have to find better ones ) Any tips ? My brain is obsessed with this problem at the moment, help please.

  4. It could be that your pH is not high enough. For the organic vat pH must be quite high - cellulose you need a minimum pH of 11-12 (for silk 10-11 and wool 10). We find the organic vat works much better with tree ripened fruit (that has become overripe) rather than fruit picked green. We love the banana or mango vat best (and peaches in the summer). The henna vat is one we use as well. We also like to heat our vat to "wake it up" before use. Test the pH first, adjust it and then heat the vat gently. Hope this gives you a few ideas. Let us know!

  5. Thanks a lot! The starter solution is a great idea! Good for a quick start as well as for activating the vat! If you keep it well closed, you can keep it long time! We look forward to visit you!

  6. Thank you so much!

    How does one use the fruit mash to restart or adjust the vat?


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