Natural Blue: Making an Organic Indigo Dye Vat with Fructose

Making a Vat with Homegrown Indigo Dye

This week, I made an organic indigo vat with indigo powder I’d grown myself. I’ve been dyeing with indigo for nearly ten years. No matter which method you use, the process is utterly enchanting. Spellbinding. It really feels like magic. For many years I have made my vats with pre-reduced indigo powder and synthetic chemicals, because that was what I first learned to use, and I felt comfortable doing it, and had good results. But when I grew my own indigo pigment, I wanted to try a more natural method.

A quick google search taught me that the “1-2-3 Fructose Vat” method was, for the most part, a quick, easy, and relatively accessible way to create an organic indigo vat. This vat, like all indigo vats, can be used to dye natural fibers blue. I’ll share what I learned below.

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Preparing the Homegrown Indigo Pigment

• If you grew your own indigo, you will need to harvest it and extract the pigment from the leaves. You can read all about how to do that in my blog post: “How to Extract Indigo From Leaves.”
• If you didn’t grow and extract your own indigo pigment, you can purchase some from multiple different online natural dye shops.

Setting Up the 1-2-3 Organic Fructose Vat

• Overview of the 1-2-3 Method: The 1-2-3 Fructose Vat Method is a way of creating an indigo vat using indigo, fructose, and pickling lime (calcium hydroxide.) These ingredients are easy to find. I bought some from Amazon. These ingredients are natural and non-toxic. The “1-2-3” refers to the ratio of ingredients in this method: 1 part indigo pigment, 2 parts fructose, 3 parts calcium hydroxide.
• Ingredients and Supplies Needed:
  • Indigo pigment (1 part, I suggest 50 grams for a medium blue shade in a 5 gallon bucket vat.)
  • Calcium hydroxide (pickling lime) (2 parts, 100 grams for my suggested recipe)
  • Fructose (3 parts, 150 grams for my suggested recipe)
  • 4 gallons of water
  • Large stock pot
  • 5 gallon bucket
  • Kitchen scale
  • Mason jar
  • Dowel
• Step-by-Step Instructions:
  1. Heat up about 4 gallons of water to a near simmer. Pour all but a gallon into your bucket.
  2. Add 50 grams of indigo pigment to a quart mason jar. Fill up the jar with the leftover hot water and stir thoroughly. Indigo does not like to mix with water, so stir for a good minute or two. Pour into the bucket.
  3. Add 100 grams of calcium hydroxide to the mason jar. Fill up the jar with hot water and stir. It will not fully dissolve, so stir for a minute and then pour into the bucket.
  4. Add 150 grams of fructose to the mason jar. Fill up the jar with hot water and stir until dissolved. Pour into the bucket.
  5. Stir the vat with a dowel for two minutes. Stir in a smooth circular motion -do not agitate and froth the liquid at all. A cluster of bubbles will form in the center of the surface. This is called the indigo flower.
  6. Put the lid on the bucket and allow the vat to settle for 30 minutes.
  7. Open the lid and check the vat. If the vat has an iridescent, oily sheen on the surface, and a clear yellow liquid below, it’s ready to use. If the liquid is yellow but cloudy, allow it to settle for 30 more minutes and check again. If your vat is not the right color, check out the trouble shooting tips at the bottom of this linked post. When your vat is the right color, you can begin dyeing, but be careful if the liquid is still very hot. You may want to wait an hour or so. If you can’t dye right away, wrap the bucket in a thick blanket to keep it warm. This indigo vat prefers to be around 90 degrees Fahrenheit.

Dyeing Wool and Cotton with the Indigo Vat

• Preparing the Fibers: Thoroughly soak natural fibers in warm water.
• Dyeing Process:
  • Submerge the fibers into the vat and let them soak for a few minutes. Do not swish around or agitate the fibers -again, you do not want to introduce any bubbles (oxygen) into the vat.
  • Slowly and carefully remove the fibers, squeezing the excess liquid out so it doesn’t splash and make bubbles. If the fibers were white to begin with, they will now look yellow-green.
  • Hang the fibers, or lay them out on a screen, to fully air out or oxidize. The color will magically turn from yellow-green to bright blue within a few minutes.
  • Once the fibers have fully oxidized, you can repeat the dipping and oxidizing process multiple times, until they are the shade of blue you want.
  • When fully oxidized, rinse your fibers until the water runs clear.

Troubleshooting

A lot of things can mess up this vat: incorrect ratios, the wrong PH, too-cold temperature, too much oxygen. Follow the instructions as exactly as possible. If you need more guidance, I highly recommend the above mentioned article about this vat method, on the Botanical Colors Website. If you keep having trouble with this vat method, there are many other methods to try. I’ve only tried one of them (thiox vat.) Some of the methods are ancient and fascinating. Each one is an opportunity for another fiber art rabbit hole. I hope you find success with whatever you delve into!