Superior Education

What is Mercerizing?

  • Cotton
  • Processing

What does mercerization mean?

Q. What does mercerized mean? I saw another brand of thread that was advertised as mercerized and noticed that none of Superior Threads' labels have "mercerized" printed on them. Is this important and why does Superior Threads not mercerize their threads? I think it's only cotton threads that I've seen labeled as mercerized, but it could have been polyester threads too.


King Tut cotton thread
From cotton boll to quilting thread
King Tut
Mercerized cotton threads have a beautiful luster

A. Mercerizing is a process of treating cotton thread (and fabric) in a caustic solution under tension, which causes the fibers to swell. This process allows dye to better penetrate the fibers, thereby increasing the luster while also strengthening the thread. While some lower quality threads may not be mercerized, any long staple and extra-long staple cotton thread is most likely mercerized even it is not labeled as such. Lower quality cotton threads are often labeled with mercerized cotton when there is nothing else to brag about. All of Superior Threads' cotton threads are mercerized. We don't print the word mercerized on our thread labels because nearly all cotton sewing threads are mercerized, so it's nothing to brag about. We also don't have room on our labels. With only a 1" diameter area for a label, we're limited on space so we print what we feel is the most important aspect of our cotton threads, "Egyptian-grown extra-long staple cotton". If we weren't restricted by space, we'd add much more.

View our infographic on cotton threads.

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