It’s been a great year for acorns. When I went for a walk in the local park a little while back, the oak trees were heavy with them, and fallen acorns thickly littered the paths. Oak trees are native to the British Isles, and their acorns were used by the Vikings and Anglo Saxons to produce a brown dye. I’d been wanting to try them as part of my experimenting with natural, foraged dyestuffs, so I scooped up a bagful – about 400g – and brought them home to soak in rainwater in a covered bucket.
After a few days the water was a kind of murky, dirty brown. I nearly threw it away right then! Fortunately I didn’t… I left it a week (and learned that acorns start to germinate when soaked in water for a week!), then simmered the acorns for an hour and left it all seeping overnight again. The liquid was a dark brown by then, which looked promising for dyeing.
Next day, I strained it all off and introduced a 100g skein of Regia for Hand-Dye 4ply yarn, pre-mordanted with alum and cream of tartar. I’ve read that you don’t actually need to use a mordant with acorns because of the tannin in them, but the jury seemed to be out on that and so I didn’t risk it.
An hour’s gentle simmer later (too high a heat is said to dull the colours of bark and other tannin-rich dyes), I lifted the lid and – ta-DAH! – I had a tangled heap of brownish wool. To intensify the colour I added a teaspoon of soda ash (which makes the dye bath alkaline) and left it another 10 minutes. The result was a lovely warm, nut brown. I’m delighted with this as just about everything else I’ve dyed with has produced shades of yellow or olive! My book on natural dyeing suggests that an acorn dye treated with an iron modifier produces shades of warm grey, so I’m aiming to go get another bag of acorns and try that next.
Meanwhile I am very pleased with my little skein of acorn-dyed yarn.
Weight of dye-stuff: 400g
Weight of yarn: 100g
Modifier: Soda ash