Super Wash Wool

A gal was in the shop last weekend and asked the question:  "What is superwash wool"?

Good question! 

After a quick internet search, we looked it up and was able to give her an answer.  But I decided to do some more reading on the subject...there really is so much to learn about our favorite subject...yarn and fibers!
I also hear people say they are allergic to wool, but while reading discovered why dermatologists think many think they are allergic...more on this in another blog.

The advent of the washing machine almost rendered wool extinct for obvious reasons.  So, to keep the world from being taken over completely by man made fibers, the wool industry started working on a way to create a machine washable wool.
Fibers are made up of tiny little scales.  They play an important role in how protein fibers look, feel, and behave.  They act as miniature fingers that help hold fibers together to form a strong, durable yarn.  They give fibers something to hold on to during the spinning process.  At the same time, they also provide a microscopic buffer between fibers, making them at once enmeshed distinclty seperate.  And scales are also the reason why a wool sweater, when machine washed in hot soapy water, will emerge a shrunken felted mass!

Textile scientists tried to eliminate the scales from the fiber.  Early efforts involved carbonizing the scales by rapidly burning them off at a high tempuerature, but this proved too harsh on the fibers, as a result it was scratchy and unpleasant.  Later developments involved applying a fine resin to the fibers, which essentially glue the scales into the fiber shaft.  Today's superwash wools may also contain biopolished wool that's been bleached to remove the fiber's protective outer lipd barrier and then treated with enzymes that literally eat away the scales.  Another source states that the scales are removed by an acid bath or it can be made by coating the fiber with a polymer that basically keeps the scales from being able to join together and cause shrinkage.
Because the scales have been eliminated in on way or another, superwash wools tend to have a denser hand and a more lustrous appearance.
Read your yarn labels.  If it reads Superwash wool, you will know that it is safe to wash and how it got that way! 
I did my homework from The Knitters Book of Yarn by Clara Parkes, and about.com