ALUM MORDANT for Natural Dyeing | Essential Fixative | Ensures Colour Fastness

ALUM MORDANT (Potassium Aluminum Sulphate Dodecahydrate)
~ Necessary for most plant dyes to ensure colour fastness ~

Alum is considered the safest and least harmful mordant used in natural dyeing. It helps fix dyes to fibres and enhances colour retention. What many don't realise is that Alum occurs naturally in nature, and some plants, such as Lycopodium, contain natural Alum.

Mordanting Cellulose Fibres

For mordanting cellulose fibres, please refer to our blog for detailed recipes:

How to Mordant Linen and Cotton Fabrics Successfully – AppleOak FibreWorks

How to Mordant Linen and Cotton Successfully Without Tannins – AppleOak FibreWorks

Basic Recipe for Wool
Ingredients:

10%-20% Alum (based on the Dry Weight of Fibre - D.W.F.)

Wool (or other protein fibres)

Water

Optional: 5% Cream of Tartar (for hot mordanting)

Instructions:
Cold Mordanting:

Weigh your dry textile material.

Soak the dry material in water.

Dissolve Alum in hot water and add to a mordanting pot filled with water.

Add pre-soaked wool and let sit for 24-72 hours.

Hot Mordanting:

Dissolve Alum in hot water and add to a mordanting pot filled with water.

Add 5% Cream of Tartar to slow down the mordant uptake.

Add wool and bring to 80°C for 1 hour.

Let cool, then rinse and dye or dry for later use.

Alum is ideal for protein fibres like wool and silk, ensuring vibrant and lasting colour results.

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