king tut threadMercerizing: What does it do?

Q. What does mercerized mean and is it important? I have some spools of thread which say 'Mercerized Cotton' and other threads, including yours, which don't say anything about mercerized. Why don't you label your threads as "mercerized"?

A. Mercerizing is a process of treating cotton thread (and fabric) in a solution, 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 marked "mercerized cotton" when there is nothing else to brag about. All of Superior Threads' cotton threads are mercerized. The reason we don't label our threads as such is because:

  • Nearly all cotton sewing threads are mercerized, so it's nothing to brag about.
  • We don't have room on our labels. With only a 1" diameter for a label, we're limited on space so we put 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.
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By: Bob Purcell