Cream of Tartar in Natural Dyeing: What It Does, How Much to Use and What to Pair It With
Cream of tartar (potassium bitartrate) is a traditional dye assist used together with alum, mainly on wool and silk. It keeps the mordant bath slightly acidic, helps the alum bind evenly, keeps wool soft, and often gives clearer, brighter colors, especially reds. This guide explains when you need it, how much to use and what to pair it with.
Shop: Cream of tartar
What cream of tartar is
Cream of tartar is not a dye and not a mordant on its own. It is an assistant that supports the alum mordant on protein fibers (wool and silk). It is rarely used on cellulose fibers such as cotton and linen.
The core pairing: cream of tartar and alum
Most dyers use cream of tartar because they are mordanting with alum. Alum is the main mordant; cream of tartar is the helper that gives more even, cleaner results on wool and silk.
Shop: Alum mordant (potassium aluminum sulfate)
How much to use
A reliable starting point for wool and silk:
- Alum: 10–15% WOF
- Cream of tartar: 5–7% WOF
WOF means the dry weight of fiber. For 100 g of wool: 10–15 g alum and 5–7 g cream of tartar.
Quick method for wool and silk
- Scour the fiber first; clean fiber gives even results.
- Dissolve the alum completely in hot water.
- Add the cream of tartar and stir until dissolved.
- Add the solution to a pot of warm water, add the wet fiber and heat gently without boiling.
- Let the fiber cool in the bath for the most even uptake.
For the full step-by-step method, read how to mordant wool and silk.
When you will notice the difference
Cream of tartar is most useful when you want clean, clear shades and even color on wool and silk, especially reds and warm tones. A classic pairing is madder: mordant with alum and cream of tartar, then dye with madder root powder or madder extract. It also works well before weld and other yellows.
What about cotton and linen?
For cotton and linen, cream of tartar is usually not what makes the difference. You will get much better results from good scouring and the right cellulose method: tannin before alum. See how to mordant cotton and linen, and browse our undyed materials for natural dyeing.
Frequently asked questions
Do I need cream of tartar for every dye?
No. It is optional and most useful with alum on wool and silk.
Can I use it without alum?
No. It is an assistant, not a mordant, so it is used together with alum.
Will it change my color a lot?
Often you will see clearer, brighter shades, especially reds and warm tones. Results always depend on the fiber, water, dye and method.
Is cream of tartar from the kitchen the same?
It is the same compound. Buying it in larger bags is simply more economical for dyeing.
Related: Alum mordant guide · Guide to mordants · Dye assists & modifiers