Indigo Reduction Materials

Michel Garcia has inspired and informed many of us in the use the organic indigo vats. He has given us a simple one, two, three (1:2:3) recipe that refers the proportions of indigo, lime (calcium hydroxide) and reduction material (often a sugar).

But nothing is ever as simple as 1:2:3! Dyers work hard to determine how to keep their vat active, when to add reduction material, when to add  lime, and how to best dye their textiles.

A key issue dyers must think about is the selection of the best reduction material that is also readily available. Michel commonly recommends the use of fructose or a fruit that is high in sugar, such as bananas. These high-sugar materials assure that the indigo vat will go into reduction quickly and successfully. I recently had a reader ask me if dextrose will work as well as fructose. I didn’t know, so I tried it. It was slower to reduce, but in the end resulted in colors very close to those obtained with fructose. On the other hand, cane sugar resulted in no reduction whatsoever.

Vats were made with fructose and dextrose

In November I was in Oaxaca, Mexico for the 10th Intentional Shibori symposium, where Michel Garcia and I were both teaching workshops. Our time in Mexico proved to be another opportunity to realize how much more there is to learn about indigo vats.

One day, we were eating fresh oranges and Michel mentioned that we could use the orange rinds to reduce an indigo vat. I was surprised (and a bit skeptical) since I knew that oranges were acidic. It turns out that the orange juice is acidic but the rinds are full of pectin, which is an excellent reduction material.  We ate a lot of oranges, cooked the rinds, and used that juice to make our vat. Of course, it worked!

Further discussion of indigo vats in Michel’s class revealed that some vegetables can also be used to reduce the indigo vat: turnips, zucchini, etc. Some of these vegetables contain pectin as well as sugars.

I never really know something until I’ve tried it. In the last few weeks I have made nine small indigo vats using citrus skins and chopped vegetables. I made the vats in glass jars with 1 gram of indigo per liter of solution.  A great deal can be learned about an indigo vat when it’s made in a transparent container. I can see the color of the vat, the amount of un-reduced material at the bottom, and the speed (or slowness) at which the vats reduce. The use of the vat for dyeing is the ultimate test.

The “citrus series” was made with

  • Cooked orange rinds
  • Cooked lemon rinds
  • Commercially available ground orange peel
  • Commercially available pectin from the grocery story (additives included dextrose and fumaric acid)

When using fruit, I cooked the rinds from several small oranges or lemons in water and used that liquid as the basis of the vat. I used the 1:2:3 proportions (by weight) as a guideline for the commercially available orange peel and pectin (1 part indigo, 2 parts lime or calcium hydroxide, 3 parts reduction material).

Samples dyed in the vat 1 day after making the vat and 9 days later. Reduction of the indigo vat is sometimes not complete for several days. The vat made with cooked lemon rinds never reduced well and continued to have a great deal of un-reduced material in the vat. All dying is a single dip in the vat.

The “vegetable series” was made with

  • Zucchini
  • Turnip
  • Carrot
  • Sweet potato
  • White potato

I used the equivalent of one medium sized vegetable per liter of vat liquid. The vegetables were chopped into small pieces and boiled for 15-30 minutes or until the vegetable matter was very soft. The liquid was then strained to make the vat.

A vat in a pint size jar is enough for testing.
The color of the bubbles on the surface of the vats is an indication of the reduction. The light colored bubbles of the white potato vat (back row, center) indicates the weakest reduction. This is confirmed by the color of the vat and the dyed color on the cloth.

Every vat worked to some degree. In the “citrus series” both the orange rind vats reduced first, the pectin vat was slow but after a week the color achieved matched the orange rind vats. The lemon rind was the weakest from the beginning and also has a great deal of unreduced material at the bottom. The white potato was the slowest of the vegetables to reduce and the resulting color continued to be the weakest.

“Vegetable vats” after 24 hours and 5 days.

Some of these latest experiments were more successful than others but they were a huge revelation for me. There are indigo reduction materials everywhere! Some are better (and more available) than others. I can imagine a new use for the abundance of zucchini in the summer garden and I can use waste from my food kitchen to feed my indigo vat.

Several years ago I was doing indigo dyeing on the Island of St. John in the Virgin Islands. We harvested local Aloe Vera leaves as a reduction material. I later tried reducing a vat with Aloe Vera that was growing in a pot as a houseplant. The houseplant did not reduce the vat.

My studio doesn’t smell as sweet after cooking potatoes and turnips as when cooking orange rinds or bananas (neither does the vat), but it’s another valuable reminder of the complex world of natural dye and the resources at our fingers.

34 thoughts on “Indigo Reduction Materials

  1. Fascinating! My vat is primarily a henna vat, but on days I’ve done a lot of indigo work I give the vat a “treat” of half a cup or so of date sugar (which is essentially ground up dates – fructose – not a refined sugar) dissolved in hot water. I do this to get the vat back into full reduction quickly after introducing so much oxygen. In my experience henna seems to be a more stable reduction agent over time, but fructose (or date sugar, which is an item I have in my kitchen already) is faster. I also occasionally cook banana and mango peels as a “treat” for my vat (yes, I do think of my indigo vat sort of like a pet :)) I never imagined I could use orange peels because of the acidity. I have orange trees in my yard; sounds like I’ll have a happy vat when orange season rolls around!

    1. I also keep a henna vat in the studio and feed it regularly with fructose, because it’s easy and always readily available. When I have extracted all the dye from a madder root bath, I’ll cook up those roots for the indigo vat.

  2. Catherine! Thank you for sharing, I love this so much! I recently heard from another natural-dyer you can use clementine / tangerine peels to make a vat, and I’ve been saving mine to experiment with…
    Were all your orange rinds fresh? Were they as effective if dessicated? I imagine the fructose would be just as concentrated, it’s only the moisture that evaporates…
    I plan to experiment with this next week.
    Be well,

    1. I’ve used the rinds fresh, and have also kept them “fresh” in the freezer until I’m ready to use. I was afraid of rotting if I didn’t dry them properly. The dried, ground orange rind I purchased from Mountain Rose Herbs worked beautifully, as you can see in the samples.

      1. Growing up in the Caribbean, we dried orange peel (rind) for medicinal use. The rinds don’t rot. Just leave them out in the open and they will dry thoroughly over time.

  3. Fascinating! I cook up banana peels, mango peels, and even coffee cherry pulp from my coffee harvest as a special “treat” for my henna-based indigo vat. I never imagined I could use orange peels because of the acidity. More wonders from our favorite French magician!

  4. Thank you so much for such an informative post.
    Where I live I’ve used mangoes as we have lots of them and now I’m going to experiment with everything in small glass pots as you did.
    Thanks again

  5. Catharine, thank you so much for this post and for all your blog. Every posting is very interesting, always with something new to think about.
    I use mainly madder, fructose or henna for this type of vat, but I have tried with onions and they worked, too. Last winter I tried birch bark but that didn’t work. Pectin is interesting, there are usually lot of rowan berries in the autumn and they are strong with pectin, so that would be something to experiment, though I don’t think they contain much sugar at all.

    I see that you use only a small amount of indigo for these experiments, and can still get dark color with one dip. Have you ever found that the ratio between liquid and indigo would be important? I use 5 grams of indigo to one litre of liquid at the least, and if I use less, then the color I get is very pale. This was when I started to use this type of vat, and since then I have made quite strong vats, so I don’t know if the first experiments with low ratio of indigo and not so good results were because of my incompetence or if the ratio matters.

    1. Thank for your comments, Leena. I have been an admirer of you blog for a long time. I find that the amount of indigo in the vat affects how long I can dye in that vat, and not so much the depth of color. When making a vat for demonstration or experimentation I will typically use only two or three grams per liter. When making a vat for studio use, I will use close to 10 grams per liter. The pectin was a real revelation for me!

      1. Thank you:)
        May I put a link in my blog to this post? I think it would give new information also to Finnish natural dyers. Your experiments are so thorough, and you explain this so well.

  6. thank you so much again for sharing this information. I’m wondering if I can use the leftover-pulp from cooked grapes after making grapes-juice? Should I grind it, because of the little pits in it, to get out the pectine?

  7. Hi Catharine. Do you know if anyone has tried using honey as a reducing agent in indigo vats? As a beekeeper I have always wondered. Honey is predominantly a mixture of fructose and glucose – some honeys contain more fructose and others more glucose (ivy honey). I know the fructose is a good reducing sugar and seeing your blog I now know glucose can be used also so perhaps honey would be ideal, though to be honest I would still rather eat the good stuff. However, I always end up with some waste honey after extracting which would be no loss.

    1. You can absolutely use honey! But as you mention, you’d rather each the “good stuff”. When reducing an indigo vat, you want to use what is available AND affordable/abundant/inexpensive… So if you have waste honey that is perfect. We have a dyer here in Western NC, who uses honey. Her family keeps honeybees but she doesn’t like the flavor. So it’s a perfect reduction agent for her.

  8. Hi Catharine! is it possible to apply a reduction agent topically to fabric to discharge on some level? I heard something about citric acid being used to lift off some indigo, but I haven’t had success.

    1. Joy and I do include a process of indigo discharge in the book. It’s based on old recipes that were used in industry. Potassium permanganate (an oxidation agent) is used in combination with citric acid. The acid alone will not discharge indigo.

  9. these posts are really helpful and I feel finally I found a good team of similar interests. I wish to know in detail the effective process of discharge printing on Indigo.

    1. I’m glad that you find the posts useful. Joy and I do present a method of discharging indigo in our book, The Art and Science of Natural Dyes (Schiffer, 2019). When combined with a printed resist, very interesting effects are possible. I will do a future post on thickening the discharge solution for printing.

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