Soda Ash (aka Washing Soda)
Used to create alkaline bath solutions.
Used to dissolve some natural dyes, such as Kamala.
Some Indigo dyepot recipes suggest soda ash instead of lye.
When using soda ash, always add soda ash to boiling water. Never add water to soda ash.
Soda ash will dissolve in boiling water. Always carefully follow recipe instructions which include the use of soda ash.
When mordanting cotton during the soda ash step, always add the dissolved soda ash into the alum mordant pot very slowly.
Steps to mordant cellulose fibers using soda ash can be found in the potassium alum instructions