Making An Organic Indigo Fructose Dye Vat

The organic or fructose fermentation vat is based on the traditional dye baths of India and Morocco. This recipe works off the proportions by natural dye master Michel Garcia and is known as the 1-2-3 fructose vat,  1 part natural indigo / 2 parts lime / 3 parts fructose crystalline.  This vat uses the reaction between lime (calcium hydroxide) and fructose crystalline to reduce the dye bath (remove oxygen) which allows the indigo to bond with the fabric fibres. 

The fructose acts as a reducing agent and the lime is the base.

Bio indigo powder derived from the plant indigofera tinctora is certified organic and complies with the Global Organic Textile Standard GOTSIII. Natural indigo is obtained through a non toxic fermentation of the indigo plant.


50gms indigo powder

100gms lime/calcium hydroxide

150gms fructose crystalline


  • dust mask (lime can be irritating)
  • gloves 
  • 2 litre heat resistant plastic container or 2 quart mason jar
  • wooden spoon or stick for stirring
  • 20 litre plastic bucket with lid or non reactive stainless steel pot
  • drop sheet
  • separate drip bucket or tray


Add your indigo powder to a 2 litre heat resistant container or 2 quart mason jar.

I like to use a mason jar so I can see the reaction take place.

Mix indigo powder with a little warm water to make a paste.

Alternatively you can hydrate indigo by putting powder in a separate glass jar with some marbles or clean garden stones, add warm water, lid on firmly and shake vigorously for a minute, your indigo is now hydrated! 

Add indigo paste/solution back to your container or mason jar.

Add 2 cups of hot water and stir.

Add lime slowly and gently and stir thoroughly.

Add fructose slowly and gently and stir thoroughly.

Add more hot water until jar is almost full.

The solution should be a dull, cloudy yellow green. Keeping it warm can help the vatting out process so you can sit jar in a pot of hot water if you wish.

Stir solution every 15 minutes or so for 45 minutes and then leave it to sit. The solution will remain cloudy and will turn a yellowish green or sometimes brown, this is ok and some sludge on the bottom is normal too.




A dark indigo 'flower' should form on top of solution and a layer of coppery scum.

Let your stock solution sit undisturbed until this happens, then it is ready to go!


It is important to scour your fabrics to remove oils and waxes that will inhibit the dye bonding with fabric fibres.

Wash your natural fibre fabric in a plant based, gentle liquid detergent to remove any residues before folding and dyeing fabric. For a more thorough scouring of cellulose fibres (linen, cotton, hemp), fill a large pot with water to cover fabric, add 2 teapoons/10mL of Synthrapol per 500g of fabric and 20g of soda ash. Simmer for one hour.


I suggest doing this before dyeing day so you are organised.



Fill your vat 3/4 full or approximately 15 litres full of hot water.

Add the entire stock solution including the sludge on the bottom.

Stir gently in one direction.

The dye bath will gradually turn yellowy green over atleast 30 minutes.

A coppery indigo flower should also develop on the top of vat and means it is ready to go.



Have a separate bucket or sink ready with warm water and submerge your folded and pre washed fabric in the water, remove and wring out excess water before placing gently in the vat.

Leave fabric in vat for roughly 3-5 minutes, then remove it trying not to drip/splash back into the vat to avoid introducing oxygen.  Place fabric in a separate bucket or drip tray while it oxidizes. Any excess dye in drip tray can be returned to the vat later.  Your fabric will turn from a yellowy green/teal colour to indigo blue when exposed to oxygen. Fabric should be left to oxidize for roughly 20-30 minutes.

For deeper shades of blue, return your fabric to the vat and repeat the process until you are happy. Aim to dye your fabric two shades darker than what you want as the fabric will be lighter once rinsed and dry.

When finished dyeing your fabric, rinse with cold water until water runs clear and untie the fabric, rinse some more.

Air dry in shade. Do not tumble dry.


Return any dye solution from drip tray/bucket back to the vat.

If you plan on using your vat more than once and over a few days, keep a small amount (tablespoon) of both the lime and fructose to rebalance the vat if need be.

If the dye vat has turned blue, do the following -

Heat vat to 50 degrees.

Add a tablespoon of fructose and gently stir.

Wait atleast 30 minutes for the vat to turn back to a yellowy green.

If this doesn't work, add a tablespoon of Lime, stir and wait for 30 minutes.

You may need to repeat the process to rebalance the vat.


You can replenish a stored vat by adding a new stock solution. 

If storing the vat, transfer dye solution to a 20 litre plastic bucket with lid. Use within 6 months.




Good dyeing!


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