Alkanet Alchemy
Alkanna tinctoria, aka dyer’s alkanet, is an herb in the Boraginaceae family native to the Mediterranean region including Central Asia, Northern Africa and Central Europe. The dark red roots of the plants are dried, then ground but interestingly are not water soluble (thereby requiring a soak in strong alcohol to extract the dye potential). The dye pigment is specifically anchusaic acid, also known as alkannin.
According to Wikipedia: “'The colour is red at pH 6.1, purple at 8.8 and blue at pH 10.” Now that is worth testing! I set out to try six skeins: two at pH 6, two at pH 9 and two at pH 10 - each time one skein premordanted with alum and the other with iron (total of six).
Start with the booze
The dye pigment is only soluble when first exposed to alcohol. I’ve been reading some folks use everclear but I went with Vodka because that’s what we had on hand. I’ve also been reading you need 80-100% WOF (weight of fiber) to get deep colours. I decided to try for 150 % WOF to be on the safe side. The 6 skeins together were 66 grams. So I weighted out 99 grams of ground alkanet into a jar and poured in 1 litre of vodka.
But for how long?
It wasn’t clear from reading accounts just how long to soak the alkanet in the alcohol for. Even Maiwa instructions just says “several days” - but the guidance was to keep soaking until the colour was dark. Oddly the colour went dark right away and didn’t seem to change at all. I ended up soaking it for two days (~48 hours).
Three bags of wool
I wanted to try two different premordants at three different pHs. I decided to put together three “packages” of two skeins each within a 1-gallon mesh paint bag from the paint store.
Popped the lid
After two days, the jar was a deep maroon colour and smelled like an orchard of vodka trees (if vodka trees were a thing, which they should be).
Long pour
Tap water was added to a pot and the jar was poured in. There was still no sign of purple yet.
The vat was simmered at just under 60°C for an hour and then split off one package of two skeins into a smaller pot with some of the liquid (enough to cover the skeins and still have it move easily). Into this side pot I added vinegar until the pH read about 4.5. I kept the skeins there for another 10 minutes within the mesh bag, exposed them to air for a couple of minutes and then rinsed it off.
Cold-blooded dye
Alkanet is sensitive to temperature and starts to deteriorate at temperatures about 60°C. I upped my usual lazy approach to temperature (I.e., basically stopping it from outright boiling) and instead used my candy thermometer to keep the heat at about 55°C.
After about 50 minutes, I moved one of the packages to a second smaller pot and added vinegar until the pH read 4.5. I was aiming for pH 6, but overshot the mark. I keep the two skeins in the pot for another 10 minutes before exposing it to the air for another couple of minutes and rinsed it off. At first it was black but rinsing it exposed a bright shade of purple.
2nd skeins out at pH 9
The other two skeins stayed in the main pot and I added washing soda by the 1/4 tsp until it reached pH 10. I waited 10 minutes and then I removed the second package, waiting two minutes and rinsed the two skeins.
3rd skeins out at pH 10
I kept adding washing soda until I hit pH of 10.5 and removed the last package.
Results
From left to right (alum premordant 16% WOF, iron premordant 6% WOF):
Alum, pH 4.5
Alum, pH 9
Alum, pH 10.5
Iron, pH 4.5
Iron, pH 9
Iron, pH 10.5
The purples came out nicely but the greys from the iron premordant are fairly bland.
Exhaust bath
After about 5-6 hours, I tried to see what potential there was in the dye bath using two skeins premordanted with alum. They came out steely/lavender grey (two skeins on the far left). I’m betting the enough alcohol had burned off during the process that the anchusaic acid was no longer soluble. I could test this out but it would mean using up even more vodka… for now.
