The Fructose Vat
Review the instructions for indigo vats. Don’t forget to scour your cloth or yarn before dyeing.
For a vat of about 8 litres
— 50 g (1.75 oz) powdered natural indigo
— 150 g (5.25 oz) fructose
— 100 g (3.5 oz) calx (calcium hydroxide)
Making Your Indigo Vat
Fill a 20L bucket or stainless steel pot with hot water (approximately. 120F/50C). If you need to bring your temperature up you can add a kettle of boiling water.
Add 50g of indigo. You can add the powder straight to the hot water or wet it out in a smaller jar and add it. Stir well.
Add 100g of Calx (Calcium Hydroxide aka Slaked Lime). Stir well in a circular motion.
Add 150g of fructose. Stir well in a circular motion for 2 minutes.
Let vat rest in a warm place for 1 hour. Stir 3-4 times throughout the hour.
Note: The vat should turn to a yellow-green colour and a bronzy film with develop on the surface. The ‘indigo flower’, or cluster of bubbles should be a darker blue. These tell-tale signs indicate that your indigo is reduced and your vat is ready to use.
Dyeing
Scour/wash your natural fabrics prior for best results. See information on scouring in our Guide to Natural Dyes.
Try doing some resist techniques like elastic bands, knots, binding, fold and clamp to create white designs in your indigo cloth.
Wet out your fabric thoroughly in warm water, this will help with evenness in dyeing. Squeeze out as much water as possible and fluff out your cloth.
Submerge slowly, avoiding bubbles, keeping the fabric below the surface.
Dip for 2-10 minutes, then remove, squeezing gently close to the surface.
Note: You can plunge your cloth into a bucket of cool water to get some of the organics off, then squeeze and fluff your fabric to allow air to oxidize the indigo and turn it from green to blue.Oxidizing takes approximately 10-20 minutes.
Repeat the steps of dyeing and oxidizing until you reach your desired depth of shade. Remember your cloth will dry lighter.You can always dip your piece again once dried and rinsed.
Once you are done dyeing, give your piece a good rinse in cool water. At this point you can open your piece if you have used any shaped resist.
Finish in a 3-5 minute soak in a bucket of water with a glug of vinegar to neutralize the calx.
Note: You can scale this recipe by halving it and using a 10L bucket, or doubling it and using a 40L bucket.
Maintenance
• It is nice to let the vat rest after a batch of dyeing.
• Keep the vat warm (40°C) and add 1tbsp of your fructose and 1tbsp of calx if the indigo liquid starts looking blue-green. Stir well in a circular motion. Let reduce for 30-60 minutes.
Disposal
• Oxidize the vat. Pour it back and forth 10 times from one vessel to another to introduce lots of air. Pour down the drain or into gravel or dirt.
Maiwa has a Fructose Kit with everything you need to make this vat.