Scouring: Dyeing from Nature

February 14, 2021

Washing and Scouring

The first step to preparing your fibres for dyeing is to make sure they’re clean and ready to receive the mordants and dyes. If you’re purchasing new fibres you need only scour them, but if you’re using second hand fibres it is a good idea to wash your fabrics using a neutral or natural laundry soap to remove any oils and dirt prior to scouring.

Scouring is a term for cleaning fibres prior to mordanting and dyeing, and does not refer to simply washing fabrics in a washing machine. Scouring is a process that will remove natural oils or manufacturing coatings from your fibres that would otherwise prevent the absorption of dyes. Some dyers choose not to scour their fibres, however there are many experienced dyers who advocate for the importance of scouring as improperly scoured items may not dye evenly and may not hold the colour well. Most fibres have coatings of some type, whether they be natural oils or manufacturing residues. If these are not removed the dye will attach to the coating and may not reach the fibre underneath, causing colour to be removed with these coatings as they are removed from the fibre over time.

If you choose to scour your fibres there are a variety of products and methods you can use to do so. The first steps to scouring will be to identify if you’re using cellulose or protein fibres, as the methods vary depending on these criteria. The next step would be to calculate the Dry Weight of Goods or DWoG. This refers to the dry weight of fibres you will be scouring, which then allows you to calculate how much detergent you need to use while scouring. I use a kitchen scale to weigh my fibres.

Basic Supplies:

- scale to weigh fibres and detergents

- alkaline degreaser for cellulose fibres (Soda ash, baking soda, etc.)

- Neutral detergent (Orvus paste, Synthrapol)

Scouring cellulose fibres: Sources give varying instructions on how to scour cellulose fibres, but many agree that it is important to use both a neutral soap and soda ash (washing soda) or sodium bicarbonate (baking soda).

In my practice I have used Synthrapol and baking soda to scour, and have been happy with the results, but again I am still a beginner and learning new things every day!

From what I have read and used myself we can add baking soda or soda ash at 1-4% DWoG to our scouring bath. As an example, I scoured an old cotton curtain with a DWoG of 260g and used 3.6g of baking soda, which is equal to 1.4% of the DWoG. Different sources cite using a higher percentage as being more effective, but it’s up to you! I chose to use a lower percentage as I was low on supplies.

For the neutral soap I have read that you can use anything from natural, pH neutral soaps to dishwashing soap. Personally I have not tried either of these options, but they are readily available and easy to find! In my practice I have used Synthrapol which is a concentrated, non-ionic soap that is used for scouring. It can be purchased from stores that specialize in natural dye materials. I have never been particularly precise with the amount of synthrapol I use, but different sources have recommended using synthrapol at about 2% DWoG, so for example you could use 5ml of synthrapol for 250g of fibres.

Another soap that has been recommended to scour specifically protein fibres is Orvus Paste. This product isn’t as strong as Synthrapol, so it may help protect the lustre of protein fibres.

Note: See my post on local stores to source scouring materials for anyone reading from Canada or Montreal specifically.

The basic process of scouring is to add your baking soda or soda ash and your neutral detergent to a water bath that will allow your fibres to move freely and then to add your pre-wetted fibres to said bath. Pre-wetting your fibres will aid in an even absorption of detergents. While scouring is a simple process, there are many ways to refine said process in a way that suits your fibres and your workspace.

For cellulose fibres there are two ways to scour:

Stovetop→

When scouring cellulose fibres on the stovetop, use a non-reactive pot that is big enough so the fabric will not be crowded. Stainless steel is a good material option as it is non-reactive.

Your first step will be to weigh your dry fibres so that you can determine how much detergent to use.
Next you will pre-wet your fibres by putting them in a bowl of warm water for approximately 1 hour.
Choose a pot in which to scour your fibres. This pot should be large enough that it will allow your fibres to float freely while they’re in the water.
Pour an inch or so of hot water into your pot and add your baking soda or soda ash, stir the water to dissolve everything. Wear gloves when handling these powders as they can be harsh to your skin.
Once powder detergent is added, add your neutral soap.
Add enough hot water to your pot so that the fabric will have some room to move.
Add your pre-wetted fabric, and add more hot water to cover if needed.
Bring the water up to a hard simmer and let it simmer for about 30 minutes . In my experience, having the water at a full boil just causes your fabric to float on top of the water and it doesn’t get cleaned as well as it could be. Stir and flip the fibres frequently throughout the heating and simmering, redistributing any tight areas that form, so the scouring water has a chance to reach every part of the fabric.
Take the pot off the heat, and let it cool down. Squeeze out the fiber and set it aside. The water will likely be slightly cloudy and dirty. If it looks very dark and murky it would be a good idea to scour this fabric again with a fresh bath.
Once your fibres have been scoured you can rinse them with warm water to remove any remaining detergent.
Your fibres are now ready to be mordanted!

Washing Machine→
If you scour in the washing machine you may have less control over the process, but it may be a simpler and safer option depending on your workspace situation.

* Scouring in the washing machine should only be done with cellulose fibres

What I have found works for scouring using a washing machine is:

Add your unfolded fibres to the machine.
Add your alkaline (baking soda/soda ash) and your neutral soap based on the DWoG of your fibres.
Use a cycle that lasts at least one hour and uses a high water level, so as to allow the fibres to move very freely.
Use HOT water (as hot as the machine produces) for both the wash cycle and the rinse cycle.
Set the machine to do a second rinse cycle, or manually rinse it for a second time.
It is now ready to be mordanted, or dried and stored!

Scouring protein fibres:

Protein fibres generally need a gentler hand throughout the dyeing process. Silk is a very fine and delicate fibre, and wool needs to be treated gently to prevent it from felting.

It is also important not to heat protein fibres to too high of a temperature. Wool and silk can be damaged at high temperatures.

Protein fibres also do not tolerate sudden temperature changes. It is important to start with tepid water and either raise or lower the temperature gradually to prevent damage to your fibres. After heating or cooling the fibres should also be allowed to come back to a room temperature before rinsing them with tepid water. So after putting silk in a heated dyebath, for example, you should let said silk cool down on its own before rinsing it.

A protein based fibre that is commonly hand-dyed is yarn. Yarn, whether it be wool or silk, has a tendency to tangle, so it’s important to wind your yarn into skeins to prevent this from happening, and to avoid creating any resists where the dye cannot reach your yarn. Please refer to this blog to see a skein winding method.

Now that I’ve gotten those disclaimers out of the way, there are two methods to scour your protein fibres.

The first method is a similar stovetop method as would be used with cellulose fibres, however we will not be adding an alkaline powder detergent such as baking soda or soda ash.

Stovetop→

When scouring protein fibres on the stovetop, use a non-reactive pot that is big enough so the fabric will not be crowded. Stainless steel is a good material option as it is non-reactive.

Your first step will be to weigh your dry fibres so that you can determine how much detergent to use.
Next you will pre-wet your fibres by putting them in a bowl of warm water for approximately 1 hour.
Choose a pot in which to scour your fibres. This pot should be large enough that it will allow your fibres to float freely while they’re in the water.
Pour an inch or so of hot water into your pot and add your neutral detergent, such as Synthrapol, or Orvus Paste (as recommended by Maiwa). Multiple sources recommend using a smaller quantity of detergent for protein fibres, so you may choose to use 0.5%-1% of the DWoG.
Add enough water to cover your fibres.
Add your fibres to this pot and heat gently.
Keep your fibres at a low temperature (60º C, 140º F) for 45minutes-1hour. Turn the fibres gently during this time, but do not agitate.
Remove from heat and allow the fibres to cool slowly.
Once your fibres have been scoured you can rinse them gently and by hand with lukewarm water to remove any remaining detergent.

Off heat method→

This method is extremely gentle, which is what protein fibres seem to demand. If you’re using fibres that have not been processed you may need to repeat this scouring process many times to adequately scour your fibres and remove all natural oils and oils used to facilitate spinning. If using store-bought, processed fibres you would probably need only complete this process once.

Your first step will be to weigh your dry fibres so that you can determine how much detergent to use.
Next you will pre-wet your fibres by putting them in a bowl of warm water for approximately 1 hour.
Fill a vessel with hot water from the tap (water that is too hot can damage your fibres)
Add your neutral detergent to the water
Add your pre-wetted and wrung out fibres to the bowl
Let the fibres soak overnight, gently turn them a few times
Remove the fabric from the scouring bath and rinse it a few times with tepid water

If you’re interested in reading guides to scouring by professionals you can get additional information from these links:

https://tashamillergriffith.com/2019/05/12/natural-dye-basics-1-scouring/

https://maiwahandprints.blogspot.com/2010/12/natural-dyes-scouring.html