After many years of sewing, crocheting, and making Kumihimo braids, I must have used miles of "mercerized" cotton without knowing just what that term means. I did a little digging and found that the process is named for John Mercer, who in 1844 developed a process to improve cotton fiber. His process of treating cotton with sodium hydroxide, then neutralizing it with an acid bath, received little notice from the cotton industry until Horace Lowe in 1890 improved the process. He found that using Mercer's process on cotton under tension improved the luster. Mercerized cotton also has improved strength, affinity to dyes, and resistance to mildew. This improved luster gave rise to the name "pearl cotton" (sometimes "pearle") that we see on cotton thread today. Not all cotton is mercerized. Un-mercerized cotton is better suited to uses where increased absorbency is needed - think dish towels.