Scouring Cotton: 1st step to dyeing naturally

by Renee Lindstrom, GCFP:  This post may contain Affiliate Links, thank you in advance for your support!  Renee



The first step for me in preparing cotton to dye is scouring it (or plant-based fabrics such as bamboo, linen or hemp). The purpose of this is to remove any fillers and additives that have been added in the manufacturing and marketing process.

To scour the fabric I use Soda Ash. Soda Ash, Sodium carbonate Na2CO3, is the water-soluble sodium salt of carbonic acid.  It is usually found in laundry soap.  In the pictures above you can see the differences in the colour of the solution before and after scouring the cotton.  The solution has turned yellow, yet, this material was washed and bleached before hand.  What has come out are the chemicals used to give the cotton a stiff finish.

I was curious about how much would come out of the fabric so I weighed one piece before and afterwards.  Here are the results:

  • Cotton weighed 15.2 oz (434 grams) before scouring
  • Afterwards it weighted 5.9 oz (167 grams)
  • That is a difference of 9.3 oz (267 grams)

Imagine 9.3 oz!  That is more that  the weight of the cotton, itself.  What are we putting against our skin and using in our homes!

The Process of Scouring

The soda ash was slowly added to the water.  Once the water became clear I brought the pot ingredients up to a boil and then added the material.  I turned down the pot and simmered for two hours stirring every 15 minutes to unfold the fabric.

  • I used 1/3 cup of soda ash in this pot of water which is about 40 grams.  

If you take your material out and the solution is grey and dirty you make wish to repeat this process before dying.

Washing Soda with no additives has been used for this process, however the amount increases 3 times that of soda ash.  The results are not as good as if using soda ash.

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One should be careful using any product like soda ash ensuring not to splash it on bare skin or breath in the chemical reaction of adding the ash to the water.  With this in mind one is advised to wear gloves, glasses and a mask.  This is not to create fear of experimenting yourself, just advice to be cautious.  If splashed, flush with water.