Dyeing yarn with black beans

cotton yarn dyed with black beans

A couple of weeks ago I dyed some yarn with black beans. The results are above, a lovely silver-blue-grey colour which changes slightly depending on what’s around it and the light. (I didn’t tie my hank very well so that pile of yarn in the background is waiting to be untangled.)

My dyeing process, which I cobbled together from many places, is below, along with some links to general info on natural dyeing.

This is what the yarn looked like before:


250g black beans (Mexican black beans, also called turtle beans)*
1/2 cup nails + a bit of salt + a bit of vinegar
Yarn (I used 200g of Bendigo Woollen Mills Cotton, in the colourway ‘latte’)
5 tablespoons of salt
Big stainless steel pot (approx 10L?)
Laundry detergent appropriate for your yarn

*I’ve read that you can use black soy beans and get a similar result (and looking at the beans themselves I can’t see much of a difference).

NB: My method includes making an iron mordant from rusted nails, but if you can buy iron sulphate in powder form, you can use that. I couldn’t find it, and couldn’t find any already-rusty nails, so I made rust the long way.


2-3 weeks before dyeing day:
RUST NAILS. Put nails (approx half a cup) into a plastic container, sprinkle with salt, occasionally spray with a mix of vinegar & water to keep the moisture up. I used cheap white vinegar and water mixed in a spray bottle.

1 day before dyeing day:
SOAK BEANS. Soak beans in water, make sure they’re well covered. Leave to soak overnight.

MAKE IRON MORDANT WATER. Boil 2.5 litres of water with 1 cup of vinegar and half a cup of rusty nails for one hour. Leave it to stand for a few hours and then pour off the water. This water is the mordant. (This mordant recipe came from here.)

WIND YARN INTO HANKS. If your yarn’s in a ball, wind it around the back of a chair to make a hank. Tie it off, using scraps of yarn in a figure-eight through the hank, at least 4 or 5 points around the hank. I recommend no more than 100g of yarn per hank. Search online for hank-winding tips. Mine ended up as a hopeless mess that I’m still working on untangling.

Dyeing day:
WASH YARN. I used my normal laundry detergent, in the bathroom sink. Rinse well to remove all the detergent, but be gentle and try not to tangle the hank. Squeeze most of the water out (don’t wring it), and keep the yarn damp.

Drain the coloured water off the beans into your stainless steel pot. (You don’t need the beans any more – you can cook with them. I made black bean burgers.)

Add 2 cups of iron mordant water to the coloured water in your dyebath.

Dissolve 5 tablespoons of salt in warm water, add to dyebath.

Make sure there’s enough liquid & space that the yarn can move freely in they pot.

Make sure the yarn is damp. Place damp yarn in the dyebath, stir gently.

Slowly increase heat, simmer for 45 mins to 1 hour, until it reaches the colour you want (remember it will lighten when it’s rinsed, washed and dried).

Allow to cool in pot. Let stand for a few hours.

If you like, you can add more iron water, to make the colour greyer. I tried this – added another cup or so of the iron water, but it didn’t seem to make much difference. If you do this, don’t add iron water when the yarn’s in the pot, it’ll be uneven – remove the yarn from the dye pot, add more iron water, stir, then replace the yarn.

Rinse well, and wash gently (I wash it with laundry detergent, so the colour when it’s dry is, hopefully, the colour it will stay after future washes). Hang to dry.

Useful natural dye info sites:
TILZ | Home-made plant dyes
Dye Man | Natural dyes
Aurora Silk | How to use natural dyes

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