There is so much about fiber that I wish I knew. I decided to do a little research about wool and I learned a lot!
Sheep were first domesticated in the uplands of Northern Iraq around 9000 BC. The first evidence of wool used as fiber to make material dates to around 4000 BC. For those spinners out there, the earliest evidence of draft spun woolen thread dates to between 4000-3500 BC. Is anyone as impressed with these dates as I am?
Aside from the long history, wool is a very diverse fiber. There are more than 200 distinct sheep breeds in existence. Each of these breeds grow different types of fiber that suit some projects more than others. Despite breed diversity all wool has some common characteristics that make it a worthy knitting fiber including: absorbency, flexibility, durability, renewability, and variety.
Wool can bend back and forth without showing signs of breaking 20,000 times. As a comparison, cotton shows signs of breaking after only 3,000 bends. Dry wool can stretch up to 30% of its original length and rebound; wet wool can stretch up to 60%. Wool is often thought of as a warm material but wool fibers have a natural evaporative cooling and heating system designed to keep sheep warm and dry. Wool does the same for us when we wear it.
Wool is a natural protein fiber that starts out deep in the hair follicle of a sheep. As the wool grows it is coated with a natural emollient; after processing it is called lanolin. Lanolin water proofs the fiber, protects the sheep’s skin, gives wool its specific scent, and helps water proof knitted garments. More highly processed yarn will have less lanolin.
The sheep that produce the wool we knit with must be sheared at least once a year. Some breeds require sheering twice a year. A skilled shearer can remove the fleece from one sheep in 2 or 3 minutes. The importance of a skilled shearer can’t be understated because how the fibers are cut make a huge difference in yarn quality. Modern and popular breeds like Merino and Cormo have deep folds in their skin that make sheering a challenge.
After shearing there are four steps that are usually followed before the fiber is sent to the mill to be turned into yarn. The first step is skirting. The nastiest of the fiber is sorted out and discarded. Second, is sorting of the fiber, which is usually done based on where it came from off the animal. The finest and softest fibers come from around the shoulders and the upper portion of the body. Then the wool is graded based on characteristics like fineness, brightness, staple length, and strength. Finally, the wool is bundled into bails and sold.
So, with all this information how should knitters pick a skein of wool? Clara Parkes, author of The Knitters Book of Wool: The Ultimate Guide to Understanding, Using, and Loving This Most Fabulous Fiber, lays out 5 steps to choosing wool. First, look at the fibers. Do they blur or reflect light back? Finer and softer wools have a lower luster. Second, shake the skein. If the wool moves on the skein it will move when knitted into fabric. If it is firm when shaken it will have more loft and bulk when knitted up. The third step is to tug lightly on one strand of the skein. A slight thinning means it will be more elastic during knitting and wearing. Worsted spun yarns tend to be less elastic but create more durable fabric. The fourth step is to smell it. If it has the pungent (I think earthy) smell of lanolin that means the fiber was processed more gently than a skein without much odor. The final step is to twist the fiber. This allows you to look for the plies and determine how many there are and how tightly the plies are twisted together. More plies and twist mean that the fiber and knitted fabric will have more strength and resilience however, too much twist is bad.
Learning about wool made me excited to be currently knitting with it! I am currently making wool socks for my mom. This information has made me look at my current fiber with a whole new appreciation. I hope you have learned as much as I have!
I got most of my research for this post from Clara Parkes’ The Knitters Book of Wool. I only hit the tip of the ice berg in regards to the information she has available in her book about wool. If you are interested in learning more about wool I would highly recommend reading it.
 Schoeser, Mary. World Textiles: A Concise History. London: Thames & Hudson, 2003.
 Parkes, Clara. The Knitters Book of Wool: The Ultimate Guide to Understanding, Using, and Loving This Most Fabulous Fiber. New York: Potter Craft, 2009.