I had heard that it was possible to dye yarns using black beans but have never tried it before so last week when I went grocery shopping I looked for some. I purchased a 500 gram bag of Turtle Black Beans from my local Waitrose grocery store.

I placed all of the beans into a large plastic jar and covered them with ordinary tap water. Overnight, the beans expanded and filled the whole jar, so then I split the bean solution into 2 jars and added more water. I let this bean stock sit on my kitchen counter for 3 days. The water in the jars started to look quite blue so I was hopeful that this would work.
Meanwhile, I spun 100 grams of white wool and divided the wool into 2 50 gram skeins.

Alum Mordant
I mordanted the wool in a 5% solution of alum and water. (5 grams of alum to 100 grams of wool) I left the wool in the hot mordant for about an hour, then I turned off the heat and let the yarn sit in the mordant solution until cool.
I then strained out the dye water from the beans into 2 plastic bowls and placed the skeins of wool into the dye solution. I refilled the bean jars with water, as I am hoping that I will be able to extract more dye from the beans.

Wool in Dye Bath
This is the wool in the black bean dye bath after about 2 hours.

Black Beans Dyepot

I let the wool sit overnight in the black bean dye bath – pH 5.

Black Beans Dyepot pH5

I removed the wool from one of the bowls and added some washing soda to the dyebath to change the pH to 9. Then I put the yarn back into the bath. Almost immediately the colour changed to more of a grey-blue shade.

Wool in Black Bean Dye pH9

Black Bean Dye Batch No. 1
On Left – wool dyed with black beans and alum – pH5
On Right – wool dyed with black beans and alum – pH9
The blue wool turned to a greyer shade of blue when the pH was changed to 9 with the addition of washing soda

Wool Dyed with Black Beans

I am pleased with the results so far. My only concern is whether they will be very colorfast or will fade in daylight. I will put some into a sunny window for the next month to see if any fading occurs.

Yes, sadly, the beautiful colours faded badly and turned gray.

Natural Dye Recipes
Tin Mordant
Alum Mordant

AMAZON – Natural Dye Books
Wild Color, Revised and Updated Edition: The Complete Guide to Making and Using Natural Dyes
Botanical Colour at your Fingertips
The Modern Natural Dyer: A Comprehensive Guide to Dyeing Silk, Wool, Linen and Cotton at Home
A Weaver’s Garden: Growing Plants for Natural Dyes and Fibers
The Rainbow Beneath My Feet: A Mushroom Dyer’s Field Guide
Harvesting Color: How to Find Plants and Make Natural Dyes
A Heritage of Colour: Natural Dyes Past and Present by Jenny Dean (2014-06-10)
Wild Color, Revised and Updated Edition: The Complete Guide to Making and Using Natural Dyes