A few weeks ago my sister texted me a photo of an announcement about a “Dyeing with Dyer’s Woad” workshop presented by a local arts group. Obviously this was something I was definitely interested in. Not because I dye fabric on a regular basis, or because I consider myself a really artsy person, but because it dealt with a weed. A weed I frequently get asked about. One I knew could be used for dyeing, but had never actually tried it. And it was science! We’re both kind of suckers for science experiments; so we signed up and had a great time. It was fun meeting new people, learning about the chemistry behind the process, and I dyed something with dyer’s woad! We took plenty of pictures along the way, so if you live in an area over run by the woad, or you’ve ever been interested in dyeing materials with natural dyes, sit back, settle in, and enjoy some cool science with me.
But first, about the woad in question:
Common name: Dyer’s woad
Scientific name: Isatis tinctoria
Family: Brassicaceae (or the Mustard family; better known for tastier things like broccoli, cauliflower, cabbage)
Life cycle: Annual, biennial, or even a short lived perennial
Flowers/Fruits: branched, small, 4-petaled, bright yellow flowers in mid-late spring that turn to smallish elliptical pods (2-chambered) that change from a lime green to very dark (almost black) purple color as they mature.
Though originally from the Mediterranean region, woad found its way to Europe and became a popular dye plant there as early as the 1st Century AD. It was used to dye everything from clothing to bodies, but eventually gave way to the use of indigo. Woad balls were often made of the leaf pulp and dried down to be crushed and reconstituted when needed. In Utah, it is generally thought that pioneer immigrants from England brought woad seeds with them to establish in their garden and use for dyeing fibers, but with the introduction of synthetic dyes the garden(s) was neglected and the woad spread like a weed.
If you want to make your own dye, it really is a much easier process than I imagined. That being said, it’s not necessarily a quick process. There are certain somewhat lengthy time requirements for different steps, but if you have an open day in mid- to late spring when the woad is in all it’s flowering glory, this is a fun project that can be carried out with regular kitchen equipment and only a couple ingredients you’re not likely to have on hand, but aren’t too hard to find either.
Ingredients and Equipment needed:
~2 lbs dyer’s woad leaves (the general rule of thumb is 4 times the weight in leaves to the weight of the fiber you want to dye)
12 quart stockpot with hot water
kitchen thermometer and timer
electric mixer or immersion blender
thiourea dioxide (though the original way of processing the dye used urine, we used this powdered chemical)
pH indicator paper
bucket with ice water
1. Collect your dyer’s woad leaves. I thought this would take a long time, but it was actually a pretty quick process (with two of us working together) to get the leaves we needed. Younger plants apparently have more of the compound that produces the dye, so try to pick rosettes (ones that don’t have the flower stalk) or smaller, younger (haven’t gone to seed yet) plants. I tried to pull them out of the ground to lessen any chances of re-growing, but be careful not to get a lot of dirt in your bucket. Pick a plant, strip the leaves, toss the stem, and move on to the next one(s) until you have enough leaves for what you’d like to dye.
2. Start soaking your fibers (muslin, wool, fabric, yarn, I think the possibilities are many) in hot water. The more soaked they are the better they will take up the dye later on.
3. Rinse the leaves of any dirt, and then cut them up into smaller chunks.
4. Bring the water in the stock pot up to 90 C or a little higher and then slowly pour in the leaves. The temperature will drop quite a bit as the leaves are added, but once it gets back up to 90 C you want to keep it there for 10 minutes, but watch it closely so it doesn’t boil.
5. After the leaves have been in the 90 C water for 10 minutes, move it quickly to the bucket of ice water to cool it as fast as possible to 50 C. You may need to change the ice/water partway through to keep it cooling down.
6. When the leaves/water have cooled to 50 C, pour it through a colander into a bucket, squeeze any liquid from the leaves into the bucket. You can toss the leaves into the garbage at this point, but pour your liquid back into the stock pot.
7. Dissolve a large tablespoon of soda ash into the stockpot. Check the pH with your pH strips – it should be a pH of 9-10. Then aerate with the mixer for 10 minutes.
8. After 10 minutes of aerating, sprinkle 2 heaping teaspoons of the thioruea dioxide onto the surface of the liquid. Don’t mix it in! From this point on, you want to be very careful about not incorporating a lot of air into it.
9. Bring the liquid back up to 45-50 C and leave it in that temperature range for about an hour.
(now comes the really fun part)
10. Gently slide the fiber into the stock pot, being careful to to splash, stir, or agitate, and leave it for at least 10 minutes. Gently pull it out of the vat after 10 minutes, gently squeeze out the fluid into another basin. Expose the fiber to the air and watch it turn from green to blue!
11. After about 15 minutes, gently slide it into the stock pot again and leave for another 10 minutes. Repeat. Each time it’s repeated, the dye in the pot is reduced, but you should do it at least twice for the best color and steadfastness.
Mountain Arts and Music – for providing the workshop
Wool Tribulations – for steps in the dyeing process
All About Woad – for the history of the woad plant
Woolery – this is one place where you can purchase the soda ash and the thiourea dioxide (spectralyte)
Weeds of the West – for the descriptive information
None of these are sponsored or affiliate links…I only wanted to share in the dyer’s woad love (or loath).