Natural Dye Workshop 9

Mordants: getting ready for color

With the exception of indigo, all the natural dyes I use are applied to the yarn by the immersion method and require a pre-treatment, a mordant, to prepare the yarn for the colorant.  Mordants insure that the dyes will better adhere to the yarn resulting in brighter colors that are fast.

The primary mordant I use is Alum (potassium aluminum sulfate) which is sometime combined with Cream of Tarter depending on the dye used and color desired.

Earthues is my source for mordants; more information on how mordants work is available on their website and in the pamphlet, written by Earthues founder Michele Wipplinger, Earthues Natural Dye Instruction Book.  I highly recommend having this pamphlet on hand as a reference when you dye.

The weight of mordant to be used is specified as a percentage of the weight of fiber (WOF) to be dyed.  I use 10% and weigh it out on a triple beam balance. 

The measured amount of powdered alum is dissolved with hot water in a 5 gal. stainless steel pot*.  The dissolved mordant is then added to water (3-4 gallons per pound of yarn to be dyed) in a larger 25 gal. stainless dye pot being heated over a flame.  The yarn is then added and periodically stirred as the temperature of the bath rises to just under boiling. 

The yarn is kept at this temperature for an hour, then permitted to cool.  The yarn is pulled from the mordant bath and quickly rinsed in a washing machine agitating it by hand; the rinse water is spun away by the machine. 

The wet yarn is now ready to dye.  It can be kept in a closed plastic bag for as long as a week before dyeing.