Rhubarb Mordant

Spring is here! This means that the time of harvest is upon us- and one of the first plants to awaken from the earth in the spring is rhubarb. 

This plant is brilliant becasue it has 3 uses: Food, Mordant, and Dye! We all know that rhubarb stalks are wonderful food. My harvested stalks will become pie later this week- I just have to set them in a bowl with water in the fridge for the next few days until I get around to making pie. The roots of the plant can make a beautiful dye- my first encounter of this as a dyestuff was with Gudrun Bjarnadottir in Iceland. her naturally dyed Icelandic wools are to die for- and I ended up taking a bunch home with me!

 The red and yellow colours are from rhubarb- the green is from cow parsley

The red and yellow colours are from rhubarb- the green is from cow parsley

Today our focus is on mordants- a necessary thing to get dyes to stick to fibres! Here is how I make rhubarb mordant:

Step 1: Harvest the leaves. Be mindful to either wear gloves, or wash your hands after harvest. These leaves contain oxalic acid (a poison!)

 First harvest of the season! Food and mordant!

First harvest of the season! Food and mordant!

Step 2: Weigh the leaves, and write down the weight in grams. Mine today was 714g.

Step 3: Chop up leaves and place in a dyepot. Please note that you need a dyepot that is no longer food safe- once it is used for making mordants or natural dyes it is no longer safe for food!

Step 4: Fill pot with hot tap water to completely cover chopped up leaves.

Step 5: Place pot on a stovetop in a very well ventilated space. Outdoors is best. Oxalic acid is toxic! You don't want to cook this around small humans or small animals. (Kids/cats and dogs) 

Step 6: Cook at approximately 180°F or 80°C for approximately an hour. Stir every 10-15 minutes. Remove from heat, and let sit for a few hours.

 Stirring the pot while it cooks down. Note: I wrote the amount of leaves on my hand as not to forget!

Stirring the pot while it cooks down. Note: I wrote the amount of leaves on my hand as not to forget!

Step 7: Strain the leaves from the liquid, and pour liquid into a glass jar with lid. Label the jar with the information you'll need later. This means what the mordant is (rhubarb leaves), how you cooked it (stovetop for one hour), and the number of grams of leaves you used (I used 714g). Since I ended up with 9 litres of liquid at the end each litre had approximately 80g of leaves in it- and I had 3- 2 litre jars and 1- 3 litre jars so the 2 litre jars amount to 160g and the 3 litre amounts to 240g. Each jar was labeled as such. I'm going to use the 1:2 ratio of this liquid- 1 part liquid to 2 parts protein fibre. 

 Finished jars of mordant!!

Finished jars of mordant!!

Step 8: Use as you wish! Make sure to only use this in a well ventilated space or outdoors!