Fiber Lesson: Wool

The end of summer means the start of crochet season. Yes, we hardcore crochet enthusiasts crochet year round, but autumn is the time when we all start thinking about cozy hats and scarves and all the wonderful things we might crochet for loved ones for the holidays. And since we’re all thinking about cuddling up with a nice warm ball of yarn, I thought now would be a good time to post a lesson on wool.

What is it?

Wool is that fuzzy fiber that the girls are petting in the photo. While it technically can come from many types of animals (such as goats, alpaca, and rabbits), when the source is unspecified, it is generally assumed to be sheep’s wool, and that’s what I am going to talk about today.

Wool is obtained by shearing it off the sheep, a harmless process similar to shaving. The sheep is allowed to spend the winter growing her full, wooly coat, which is then sheared at the start of the warm Spring months. It’s not much different from shaving a dog for the summer, except that the fiber actually gets put to use.


  • Wool is famous for its warmth and as such has been the go-to fiber for winter coats for centuries. Those Victorian capes don’t look very warm for all their thinness, but considering that in the 19th century they would’ve been made with genuine wool, the wearer was actually probably quite toasty.
  • Wool is fairly elastic, meaning that it is less likely to get stretched out of shape with wear because it tend to bounce back to its original shape.
  • Wool repels water. This fact is not very well known today, but back in the days before disposable diapers, many babies wore woolen “soakers” or shorts over their cloth diapers to prevent any, ahem, “contents” from leaking onto their outer clothes.
  • Wool can be a fairly strong fiber, depending on how it is spun. A tighter twist generally equates to a stronger yarn, but it also tends to be a rougher yarn. Most yarns try to strike an ideal balance between strength and softness. That said, even the softest wool yarns are resistant to breaking thanks to wool’s natural elasticity.
  • Wool loves to be dyed and is very resistant to color fading.
  • Some wool yarns can feel scratchy against the skin. This is why I like Casacade 220. They spin it with a softness that prevents the yarn from becoming irritating.
  • While untreated wool absolutely must be hand washed, superwash wool is machine washable. Wool is made superwash by either treating it with an acid bath or coating it with polymer or resin, a process that also reduces the elasticity of the yarn. Wool that has not been treated this way is subject to felting (i.e. extreme shrinking and matting) when machine-washed, so be sure to check the yarn label for washing instructions.

Recommended Uses

  • Wool is the perfect go-to fiber for winter wearables. Not only is it warm, but its water-repellant properties will also keep the wearer dry in wet weather.
  • If you like kitchen projects, wool is ideal for tea cozies and pot holders. The fiber is actually considered a natural flame retardant, and its insulating properties will keep heat from seeping through.
  • Unfortunately wool is not for everyone. Some people are particularly sensitive to the texture of the fiber, and some people are outright allergic. If you’re making a project with someone specific in mind, be sure they are not sensitive to wool first.


In the event your giftee has a wool sensitivity or you want to use a less expensive fiber (pure wool, while not the most expensive fiber, is also not the cheapest), acrylic is a great substitute. It is similar in elasticity and is more cost-effective. If you’d like to stay with a natural fiber, alpaca is the recommended substitute for those with wool allergies, but it’s usually much pricier. Beware of substituting with cotton, silk, or linen; these yarns have poor elasticity and will produce a much different result than wool.