Indigo dyeing ice extraction method

I’ve done loads of acid dyeing, and a little bit of natural dyeing, but I’ve never dyed with indigo before. This year I decided to grow some woad, then did a little research about how much pigment it gives and worked out that with an average yield I’d need around 7 plants worth of leaves to dye a 50g skein of yarn. I didn’t want to fill the entire garden with woad, so decided to hunt for something a little stronger. It just so happened that a couple of days after I made this decision, these lovely cards with free seeds were advertised on ravelry. I bought the japanese indigo and madder ones, and soon had lots of lovely seedlings. The madder won’t be useable for another year or two, but the indigo has been ready for its first cutting for a while. I realised I’d been putting it off as the idea of making an indigo vat was a little daunting; there are so many methods, so many people reporting problems, so many things to check. I couldn’t even decide if I wanted to dye immediately or extract the pigment for later, and I didn’t want to waste my precious leaves by messing it up. Eventually I realised I’d better get on with it or the amount of pigment in the leaves would start to drop as it got closer to flowering time, and after a little reading around I came across the ice extraction method, which seemed quick and simple and gives more turquoisey results than a standard indigo vat. I couldn’t find anywhere that explained the chemistry of what is going on with this method, so I followed instructions a little blindly, but it worked out well in the end. This is what I did.

First, I prepared everything indoors. All the websites I read stressed the need to get this done quickly, and keep everything ice cold, so I figured getting everything ready first was a good idea.

I put a couple of cups of water in the food processor along with a few ice cubes

P1270248

I got a bucket with a few inches of water in and again put a few ice cubes in

P1270249

I wound the yarn I was using, and put it in to soak in cold water. I wound off a skein of wooltops poldale/nylon sock yarn into five 20g minis, and also grabbed some silk yarn that had been lying around for years to use up anything left in the dyebath after doing the sock yarn.

P1270250

I set up a way of straining the liquid into a vessel. I decided to use my stainless steel dyepot even though it’s way bigger than I needed simply because it was there and easy to use and clean. I then lined a sieve with a mesh lingerie bag that I use when I wash fleece.

P1270251

Once everything inside was set up, I headed out to collect some indigo. Our growing season here in the UK isn’t long enough for indigo to flower and make seeds to use the next year. I’m trying a couple of methods to get round this, the first being simply growing in the greenhouse. The second is growing in a pot, which I can bring indoors when it starts getting colder outside. I read that the greenhouse plants should have more pigment in, and I didn’t want to waste the best stuff, so I decided to go with the pot-grown plants (you can see the madder in the pot on the left).

P1270252

I cut a couple of bunches of stems and put them into the bucket of cold water. I don’t know if this is necessary, but I figured it couldn’t hurt.

P1270254

It’s perhaps 2 plants’ worth, plenty left for next time, and of course it will carry on growing for a second harvest in autumn. I weighed the leaves once I got indoors, and ended up with 270 of plant material, 90g of which was stems. These numbers aren’t completely accurate as there were some water drops on the plants as I weighed them, but they give a general idea.

P1270255

I took the indigo back indoors and began stripping the leaves off the stems and putting them in the food processor.

P1270257

Once it was full, I turned it on and gave the leaves a rough chop to make more room. I repeated this a couple of times until I was out of leaves and left with this lovely green goop.

P1270259

I poured this into the strainer and then squeezed the mesh bag to get as much liquid out as I could. The squeezing produced a large amount of bright green foam as well as the dark green liquid.

P1270260

My dyebath was ready! I squeezed the water out of two of the miniskeins (which I shall imaginatively name 1 and 2) and dumped them in, squishing them around a bit to make sure they were fully saturated.

P1270261

It was at this point I knew I did indeed have some indigo pigment in there, as my nails were starting to turn blue.

P1270262

After 10 minutes, I took the skeins out and squeezed out as much liquid as I could, then added skein 3 to the dyebath. A minute or so later, I put skein 1 back in.

Skein 2 looked like this, and my mesh bag must be made of nylon as it is also a lovely shade of blue

P1270265

While waiting for the next skein to be ready, I cleaned up, including putting all the used leaves into a jar. I’ll finally be brave enough to make a fermentation vat soon, and these will be added as I’m sure there’s some pigment left in them

P1270266

After a further 10 minutes, skein 3 came out for good, skein 1 came out and went back in, and skein 4 was put in.

P1270267

After 5 minutes this time I removed skein 4, leaving skein 1 in for a bit longer and adding the silk yarn.

Here’s skeins 2, 3 and 4 side by side straight out of the dyebath

P1270269

I left skein 1 in there for another half an hour or so, and after an hour I gave all of the skeins a rinse in cold water to remove any excess green dyebath that wasn’t actually bonded to the yarn. The silk is still drying, but the sock yarn is done!

P1270272

To recap, left to right

1. Stayed in for about an hour in total, removed and squeezed out from time to time
2. First dip. 10 minutes
3. Second dip. 10 minutes
4. Third dip. 5 minutes
5. Undyed

This shows that most of the pigment was sucked up in the first 10 minutes by the first two skeins that were in there. Not much extra pigment was added to skein 1 despite it being in the dye far far longer than the others. There was enough left to give very pale colours on the later skeins though, giving a lovely gradient.

It was a very easy process, and far less daunting than a vat I have to test the pH of and really aereate at one point but be very careful not to aereate the rest of the time, and it gives lovely colours. I will be brave enough to do a proper vat soon though, I want to try getting some darker blues, and I also want to try working with cotton, which I didn’t try at all today as I read that this process works way better with protein fibres.

Leave a Reply

Your email address will not be published. Required fields are marked *