Just to keep all of us knitters on our toes we also see more than one definition for the word worsted. It can mean a yarn weight category, a type of yarn or the fabric made from this yarn. The name comes from a place, Worstead, a village in the English county of Norfolk. This village, was at one time a manufacturing centre for yarn. For knitters, a worsted weight yarn means a medium weight yarn, which in stocking stitch knits at a gauge of 16-20 stitches for 10 cm or 4 inches. I'll point out that this range has expanded over time with modern knitters, a greater variety of fibres available and more spinning processes.
There's a great article here on Knitty written by Jillian with more photos and swatches. She's a spinner so she can see some of those extra details of difference which aren't immediately obvious to me.
When we refer to worsted as a type of yarn or fabric we mean the processing.
So first we need to know about carding and combing in relationship to the source fiber.
Here's a hand carder:
Here's a hand comber:
Industrial applications use much larger mechanized versions.
The word worsted comes the world of spinners, it refers to yarns spun from parallel fibers that have been processed to remove the shorter length fibres. Most of the fibres left to be included are 3 inches or longer. The fibres are carded and then combed. They are spun in a method which keeps them in alignment. Often finer diameter fibres are chosen to work with. This yarn is twisted more tightly during the spinning process. It is lighter in weight, smoother in appearance and more durable. In the form of fabric it holds creases better than woolen yarns and is less likely to sag out at knees and elbows. Worsted yarn is described as less elastic but stronger and less irritating to the skin. It can be yarn for knitting or yarn to be woven into fabric.
|Smooth Worsted weight wool fabric|
Woolen yarns are spun from carded fibers in a more airy, random arrangement. The shorter length fibers (1-3 inches) are not removed. Coarser base fibres are used to process for woolen yarns. The yarn spun in the woolen method is very springy and has more bounce. It also is weaker and feels slightly scratchy against the skin as the shorter fibres stick out more from the surface of the yarn. It appears softer and fuzzier with a halo even though it doesn't feel softer.
|Woolen fabric with more loose fibres on the surface.|