1-2-3 Indigo Fructose/Lime vat

I have read several times about Michel Garcia’s indigo vats – in reports from the ISEND natural dye conference in France, in posts on Helen Melvin’s blog and most recently in an article by Jane Deane in The Journal for Weavers, Spinners and Dyers. Michel Garcia is a bio-chemist who has been researching indigo dyeing for many years and he has developed indigo vats that are simple to make and ready to use in a short space of time. Michel wants his environmentally-friendly methods to reach as many dyers as possible, so I decided to try out one of his recipes and then pass on the information, so others can use it too.

The vat I have tried is his 1-2-3 vat, so called because of the proportions of the ingredients used: 1 part indigo, 2 parts slaked lime (calcium hydroxide) and 3 parts fructose. This means that for 10gm indigo you would need 20gm calcium hydroxide and 30gm fructose, for 20gm indigo you would need 40gm calcium hydroxide and 60gm fructose and so on. Calcium hydroxide or slaked lime should be available from builders’ merchants but I bought mine on the internet from Amazon. I purchased fructose from our local health food shop but it may also be available in some supermarkets. For my  trial vat I used 1 teaspoon indigo powder, 2 teaspoons calcium hydroxide and 3 teaspoons fructose.

NB Calcium hydroxide should be handled with caution. It can irritate skin and lungs and cause serious injury if it comes into contact with the eyes. Do not pour water onto it but add it slowly to water.

To make the vat, start by putting hot water (around 40C to 50C but no hotter) in a dye pot or heatproof strong glass jar. Mix the indigo powder with hot water to make a smooth paste and make sure no gritty particles remain unmixed. (Jane Deane’s article gave a useful tip for mixing this indigo paste: put the powder and water in a small container with a well-fitting lid and add some marbles (or marble-sized smooth stones). Then shake vigorously to incorporate all the indigo particles in the solution. I’ve tried this and the marbles really help to make a smooth paste.)

Add this indigo solution to the hot water in the vat or jar, then stir in the calcium hydroxide. Finally add the fructose and stir well. The vat may take up to 45 minutes to be ready but mine was ready to use in about 5 minutes. The vat can then be used in the same way as other indigo vats. One recommendation was to add the fibres dry, rather than wetting them first, but I forgot this and wetted out my wool skein automatically, as I usually do, and it didn’t appear to matter. I suspect this recommendation probably refers mainly to cotton and silk fabrics, which I often add dry to indigo vats anyway. Another suggestion was that the pH of this vat might be too high for wool. However, my vat was pH11 but I dyed wool in it without any obvious ill effects. The wool remained in the vat for about 30 minutes and dyed to a mid-blue; further dips didn’t increase the depth of blue. I also added some silk fabric and a cotton skein to the vat and both dyed to a similar shade of blue as the wool. Jane Deane’s article implies that this vat is likely to produce only pale to mid blues but the lack of a deep blue from my vat may have been because I only used 1 teaspoon of indigo to make this trial vat. Anyway, I shall experiment further with this method and see whether deep blues can be achieved.

I found this method of indigo dyeing extremely simple and effective and, if it also dyes deep blues, it could be very useful.

This shows the vat with the ingredients added

This shows the vat ready to use

This shows the wool skein in the vat

This shows the skein on removal from the vat

This shows the dyed wool skein

13 replies
  1. Sandra Rude
    Sandra Rude says:

    Sounds like a lovely, easy recipe. Even easier than the one I've been using, so I may have to give it a try! I would imagine that using a larger quantity of indigo (and proportionately larger quantities of the other ingredients) would give a darker blue. Thanks for posting about this one.

  2. Debbie
    Debbie says:

    Great to see your results, Jenny! I've just got some calcium hydroxide and fructose in stock so I'll be looking forward to giving this a go myself. I wonder how it would work with woad? One for my "things to try" list I think!

  3. Dot
    Dot says:

    Very interested to see that you have tried this method. I have read the review of Michel Garcia’s new DVD in The Journal and am thinking about getting a copy, and Jane’s article is super.

    I wonder if the slaked lime on Amazon comes with instructions for safe handling? I worked for several months at one of the quarries where this product comes from (Tunstead Quarry, Buxton) and recall that there were serious hazards due to its high alkalinity and getting it in your eye can cause sight loss. I would want safety goggles as well as full skin protection when using it. If it is a fine powder, dust mask also.

    • Jenny Dean
      Jenny Dean says:

      You are right to urge caution, Dot. As with all chemicals, care should be taken when handling calcium hydroxide. According to the information I have read, it is not officially classified. However, it can cause serious eye damage if it comes into contact with the eyes and it is irritating to skin and lungs. It should be treated as an “irritant”. Water should not be poured onto it but it should be added to water. It is advisable to wear a face mask whenever handling fine powders and eye protection may also be advisable.

  4. Jane
    Jane says:

    I come to this rather late in the day as I've been away, but the 1-2-3 vat will only produce pale blues. Michel uses a henna vat (or banana, pears, pomegranates, etc.!) for darker blues, and an iron vat for the deepest shades. I must re-read my notes!
    The pH is a bit high for wool but it doesn't seem to have a negative effect on silk. And the same process works with woad extract as well as indigo..

  5. clothogancho
    clothogancho says:

    Hi, Jenny, we tried these methods in a workshop with Michel (banana, henna, madder…) : if you want darker blues you must put more indigo in the vat (for example : 20 gr of indigo, 3 bananas, 2 spoons of calcium hydroxyde, or 25 gr of indigo, 50 gr Calcium Hydro, 100 gr of henna), respect 40° with the wool and PH 10 or 11 (no more, it destroys the wool) and dip more than one time. In fact, Michel said that the more important element in the "recipe" (he doesn't like this word) is the proportion of the WATER you use ! In those cases, we put approximately 5 liters.

  6. clothogancho
    clothogancho says:

    another thing : you can keep the same vat for a long time but every time you use the vat, after working, you have to put fructose, and then, before a new work, you add calcium hydro to rectify the PH (wool = ph10, silk=ph11, cotton=ph12).
    (My name is Muriel, Alice is the system to connect with the web!!!)

    • Jenny Dean
      Jenny Dean says:

      Thanks for this extra information & my apologies, Muriel, for thinking Alice was your name. Sometimes it can be difficult to work out the name of the writer of a comment.

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