How to Make an Alum Mordant

A simple how to recipe for making an alum mordant, used for natural dyeing

Alum Mordant

Natural dyeing is usually a 2 step process. The yarn or fibre must be soaked in a mordant,
that prepares the fibre to absorb the natural dye substance.

Alum Mordant
Alum Mordant

Difficulty Level:
Average
Time Required:
90 minutes
Here’s How:

  1. Use clean, scoured wool or yarn.
  2. Fill a large pot with clean water and heat.
  3. Weigh the yarn or clean, dry fleece.
  4. Using 10% Alum (potassium aluminum sulfate) to weight of fibre, mix the Alum into the hot
    water.
  5. Using 5% Tartaric Acid to weight of fibre, add the Tartaric acid to the hot water
    mixture.
  6. Rinse the wool so that it is damp.
  7. Add the wool or skeins of yarn into the hot Alum mixture.
  8. Make sure that the wool is all covered by the water, if not, add more water to the
    pot.
  9. Simmer the mordant mixture for x-about an hour at 90 degrees Celsius.
  10. Remove the yarns from the Alum mixture.
  11. Don’t discard the leftover Alum mordant. The Alum mixture can be reused by adding more water and 1/2 the amount of Alum and Tartaric
    Acid.

DyeingTips:

  1. If dyeing skeins of yarn, make sure that the skeins are tied securely, but loosely in at
    least 3 places, to avoid tangling.
  2. The mordanted yarns can be dyed immediately, or dried and stored for later natural
    dyeing.
  3. The alum/tartaric acid mixture is suitable for wools, silks and other protein
    fibres.

How To Mordant Cotton and Linen
How To Make a Tin Mordant
How To Wash Fleece
Natural Dyes and Mordant Recipes
MSDS – Aluminum Potassium Sulfate

Where to Buy Alum Mordant
Dyeing Crafts
Wild Colours
Earthguild
Maiwa Handprints

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
The Art and Craft of Natural Dyeing: Traditional Recipes for Modern Use

Author: Paivi Suomi

I've had an interest in weaving, looms, yarns and textiles since I was a small child. I learned to knit, crochet, sew, do needlepoint at my mother's knee. My grandmother was a Saami from northern Norway. I am very interested in studying more about traditional Saami and Finnish style weaving and handicrafts. Paivi Suomi