Mercerization | Sewing Term

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Learn how the mercerization process effects the outlook of fibers commonly found in your fabric and used in your sewing projects. The Sewing Loft

Mercerization –



  1. to treat (cotton yarns or fabric) with caustic alkali under tension, in order to increase strength, luster, and affinity for dye.


You might sometimes hear the term, “mercerized cotton.” Mercerization is a process performed on cotton materials such as fabric and thread. The fibers are treated with a strong caustic soda solution. The solution only takes about a minute to “set”, then the fibers are washed clean and stretched to prevent shrinking.  

This process makes the cotton stronger, more lustrous, and more vibrant when dyed.  This process is used on both thread and fabric. 

Click photos to learn how mercerization effects your sewing supplies and tools. 

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  1. Thanks for this explanation. Does this mean that mercerized cotton won’t shrink, or that it won’t shrink as much or may not shrink? I have just assumed that all cotton will shrink and so I wash before cutting. Is this necessary? Thank you.

  2. I love the wooden spools. I use the larger empty ones to hold ribbons, embroidery flops or anything I am trying to keep from tangling.
    Heather how can I email you directly with a question I have?

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