Preparing wool yarn for dyeing need not be complicated or expensive. It’s quite easy and can safely be done using supplies you may already have at home. When using home and kitchen supplies it is important to stay non-toxic. Many modern mordanting and dyeing ingredients are toxic and require dedicated equipment. Here is a how to guide to help you safely mordant wool yarn for your wild dyeing project using kitchen supplies. This is an excellent method for beginning dyers or for those dyeing with children.

Materials:

Wool Yarn. Unless you feel like doing math, keep the yarn weight in multiples of 100 grams.
Alum
Cream of Tartar
A large non-reactive pot
Measuring spoons
A small bowl
Heat Source
Tongs
Yarn or String for tying

How to choose yarn.

This article covers how to mordant animal fiber yarn. Plant fibers such as cotton and animal fibers such as wool and silk have different processes for dyeing. Wool and hair from sheep, alpaca, rabbit, and goat will all dye with this method. Silk is made from the silkworm and therefor is also considered an animal fiber. However, this article is focused on sheep wool.

First, you need to start with a high-quality ethical yarn. For this project, I used Briggs & Little yarn from Canada that I purchased in the United States through Maritime Family Fiber. This has been a wonderful company to purchase from.

Yarn from Merino sheep can be ethically problematic, especially if sourced from Australia. Merino sheep have wrinkly skin. All sheep have a problem with a disease called Fly Strike but the Merino is more susceptible. Fly Strike occurs when fly maggots burrow in the wool and eat away the skin around the tail area of a sheep. Fly strike is the reason why lambs have their tails docked. The wrinkly skin of a Merino makes a sheep more likely to get fly strike. Unfortunately, some people remove skin around the tail of Merino sheep in a process called mulesing. Ethical yarn companies selling merino yarn will feature mulesing free yarn.

Choose your yarn based on your needs. Different projects require different weights or properties of yarn so be sure to pick the correct one before you put the effort into dyeing.

What does mordant do?

Mordanting your yarn is the first step in dyeing. A mordant opens up the yarn fibers so that the yarn is ready to accept dye. Many dyes require mordant, or the dye will not set and will instead wash out. There are a few dyes, such as an indigo dye vat, that do not require mordant. Dyeing yarn is both an art and science. Experimenting is almost the only way to learn. Most wild dyes and plant dyes, such as Nettle and Dyer’s Chamomile, require a mordant. Luckily, these natural dyes also work well with natural mordants.

What is a safe mordant to use?

Alum, or aluminum phosphate, is a safe mordant. You may be able to find alum bulk in your local bulk foods store or in your local grocery store in the spice section. It is nontoxic and is often used for pickling and preserving. It can cause respiratory irritation if inhaled, so if you are sensitive be sure to mordant your wool outside or have plenty of ventilation.

Cream of Tartar, or potassium bitartrate, is also used in the mordant process. It helps to keep the yarn soft. Cream of tartar is another nontoxic ingredient used as a food additive. You should also be able to find cream of tartar in either the bulk section or the spice or baking section of your local grocery stores. Crafty parents will quickly recognize this ingredient as something often called for in homemade play dough recipes. You will see cream of tartar in homemade baking powder recipes as well.

Using both these ingredients will help prepare your wool yarn to accept dye.

How much mordant?

Ok, you may have to use a little bit of math for this one. The recommended mordant amount of alum is 12% of the weight of your fiber (or WOF). The recommended amount of cream of tartar to add is 6% WOF. If you are dyeing very deep colors, you may want to experiment with a higher mordant percentage.

To keep it simple, for every 100 grams of fiber use 1 tablespoon of alum and 1 1/4 teaspoons of cream of tartar. 100 grams is roughly equal to 3.5 ounces.

Mordanting Process

When mordanting yarn, the most important thing to know is that wool yarn will felt with quick temperature changes. It is important to prevent rapid heating and cooling of the yarn. It also is important to handle the yarn in a way to prevent tangles as you handle the wet yarn. Many dyers use dye rings to accomplish this. Yarn or string is an acceptable substitute. Simple loosely tie the yarn in organized large loops. Do not tie overly tight because you want the water to reach under the tie strings, shown below in yellow.

To prepare the mordant, pour 1 cup or so of near boiling water into a small bowl and add the correct amount of alum and cream of tartar. Stir to dissolve.

Add room temperature water to a large non-reactive pot such as a soup pot. Add enough water to cover the yarn. Stir in the water with the dissolved alum and cream of tartar and stir. Gently place the yarn into the water being sure to fully immerse the yarn. Tongs or a large spoon work well to handle the yarn. Add more room temperature water if needed. Do not stir at this point because you do not want to overly agitate the yarn.

Slowly bring the water to a very low simmer. Do not boil. Simmer for 45 minutes while occasionally rotating the yarn with a spoon. After the simmering is finished, turn off the heat and let the yarn sit in the water as it naturally cools to room temperature, or overnight. You can place the pot covered in a cool area or garage if needed. When cool, use a spoon or tongs to gently lift the yarn out of the mordant water and let the excess water drip off. Do not wash the yarn. The yarn can be immediately dyed, refrigerated wet for a few days before dyeing, or dried on a rack for later use. Be sure to label the yarn as being mordanted because the yarn will look exactly like unmordanted yarn when dry. The mordant will hold for 3-5 years minimum and likely longer.

How do you dispose of the mordant water?

This mordant water can be reused for one more batch of yarn if you choose. The leftover water is safe to pour on acid-loving garden plants such as blueberries, huckleberries, azaleas, hydrangeas, rhododendrons, and camelias. The excess water can also safely be poured down the drain of municipal systems but if you live with a septic, choose a nice acid loving plant to water instead because the water is slightly acidic and can alter the pH of your septic.

How to Mordant Wool Yarn with Nontoxic Kitchen Supplies