When it comes to cotton yarns, there are mercerized and unmercerized cottons. Which is preferred? Truly, it depends on the end game...what you're going to make with it.
Cotton is naturally unmercerized. In their natural state, cotton fibers are typically short, so when they are spun into yarn, they tend to stick out and become become fuzzy. This fuzziness lends a softness to fabrics created with unmercerized cotton. This makes fabrics knit or woven with unmercerized cotton exceptionally nice against the skin, so wonderful for face towels, cotton tees, baby garments and blankets, and more!
Because unmercerized cotton's fibers are short and unruly, unmercerized fabric can wear out quickly. In 1844, John Mercer, an English textiles pioneer came up with a process that "tames" the fibers. This "mercerization" process gives cotton extra strength by fusing the fibers together. Mercerized cotton is, thus, stronger and more resistant to mold and mildew. Though still absorbent, it absorbs moisture more slowly, so it takes longer to become saturated (which is helpful when you're staring at a full sink of dishes!).
Pros & Cons of Each
- unprocessed; natural
- softest against the skin; becomes softer with age
- super absorbent; can quickly become saturated
- more fragile; tends to wear out more quickly
- color fades as fabric wears
- colors tend to be softer, more muted
- can shrink significantly
- chemically processed for added strength and durability
- smoother than natural cotton
- absorbent; can sometimes feel slightly water resistant (especially in very tight weaves)
- retains dye so looks newer longer; colors pop
- can have a slightly shiny appearance; also referred to as "pearl" cotton
- shrinks less, as its natural properties have already been altered by the mercerization process