My Love Affair With Wool

image of Rambouillet Merino Sheep
Rambouillet Merino Sheep Breed
(the Fleece and Fiber Sourcebook, Deborah Robson and Carol Ekarius, 2009)

Wool is the oldest protein fiber, and by far is the  most popular fiber to knit with. Wool is the hair grown on sheep, and is so preeminent that knitters often describe any yarn as “wool”, regardless of its fiber content. It certainly is my favourite to knit with for its amazing properties, but also because of its wearability over any other natural or synthetic fiber. I would say that the majority of my projects are 100% wool fiber, or a blend with other natural fibers. Let’s look at why wool is such a beloved fiber.

What is wool?

Wool is the hair fiber grown on sheep. Globally, sheep livestock are kept far more than any other farm animal. There are around 1400 sheep breeds that exist worldwide. Wool fiber is as varied as the sheep on which it grows. The term “Virgin Wool” is the wool taken from the lamb’s first shearing, and also means wool that has never been used, processed or woven before.

Factors Important In Yarn


Fineness of the fiber is often measured in terms of the fiber diameter in microns. The smaller the micron count, the finer the fiber. Merino wool, the most common fine wool used in hand knitting yarns ranges between 18 and 24 microns. The finer the fiber, the softer it feels against the skin.

Fiber Length

The natural length of a fiber, or its staple length varies depending on the sheep breed. Generally, the shorter the fibers, the softer the hand. But in terms of wearability, shorter fibers work themselves out of the fabric more easily, eventually pilling. Longer staple fibers may not feel soft, but their wearability is far better. I’ve knit sweaters, now over 15 years old, made of coarser wool fibers that have absolutely no pills. When durability or abrasion concerns are important to a project, longer wool fibers are the way to go.

sweater images knit out of coarse wool yarn
My two favourite sweaters knit in coarse wool.

Crimp or Curl

All wool fibers have crimp to them, just as some people have wavy or curly hair. Crimp in fibers helps them trap air, and absorb moisture, making the fabric warm. The waves running down the length of fine wool fibers are not as curly as long wools. Contrary to what you might think, fibers with less crimp have more bounce, loft and warmth. Curlier fibers tend to flatten out into dense, lustrous yarns.


The surface of a wool fiber is covered with scales, that vary in size, and they also determine the fineness and coarseness of wool. Fine, soft wool has as many as 2000 scales per inch, whereas coarse wool has as few as 700 scales per inch. These scales are responsible for the “itchy” feel people complain of, particularly with coarse wools. These scales are also responsible for the felting or shrinkage of wool. The most luxurious, fine, soft wool comes from breeds such as Merino, which dominate the world sheep industry. Icelandic breeds produce a coarse, scratchy fiber that is highly durable and popular for outerwear. Both fine and coarse wool are suitable for a variety of knitting projects.

Wool is not machine washable, so textile scientists created a special treatment to eliminate the scales, and render wool machine washable. “Superwash” is a finishing process that alters the scale structure. Bleach is used to remove the lipid layer of wool, followed by enzymes that literally eat away the scales. Superwash wools have a soft, dense hand, and a more lustrous appearance. I’m not a fan of superwash wools, except for Merino sock yarns, which carry exceptional properties.

The main drawback of superwash wools is the potential to stretch during washing. The reason for this is the fibers now lack scales, that normally hold the fibers together in a yarn.


Lanolin is an oily substance secreted by the sheep’s sebaceous glands. It helps to repel water from the environment, and protect the sheep’s skin. When processing wool, it is cleaned to remove the lanolin or left au naturel. The removed lanolin is used in a variety of products such as skin creams. Traditional Fishermen’s sweaters were made from lanolin-rich yarn to keep the seamen warm and dry. Lanolin is also responsible for skin sensitivities in some individuals. Some knitters are a fan of lanolin left in the yarn.

Woolen-spun Yarns

This is the most common and inexpensive method to spin yarns. The fibers are pulled out of their natural jumbled state, where the fibers are oriented in all directions, followed by twisting. The result is an airy, springy, soft  yarn.

Worsted-spun Yarns

A spinning technique that goes further than carding; the fibers are moved through mechanical combs that fully align the fibers parallel to each other. This creates a smooth, strong and long wearing fabric. Note: Worsted yarn is also a term used to define a weight category of yarn labelled with number 4. The difference is worsted-spun yarns can be made in nearly every weight or thickness.

The Properties That Make Wool So Desirable

Wool has special characteristics; it’s flexible and elastic, making it easy to knit with, as it glides across your needles. Wool is resilient; it can be bent again and again, springing back into its original shape without stretching. It wears well and resists wrinkles. Think of wool trousers worn all day, and after hanging in the closet over night, the wrinkles miraculously disappear.

Wool is different than any other fiber because it’s comfortable to wear in both warm and cool climates. Why? Wool is uniquely “hygroscopic”, absorbing up to 1/3 its weight in moisture, shedding liquid easily, and at the same time does not appear to absorb moisture. The fabric breathes, feeling warm and dry against the skin. This property makes it a favourite for items such as hiking socks and outdoor sweaters. I have found that for all the hype about the “wicking” of synthetic fibers in athletic clothing, wool performs far better.

Wool is naturally flame retardant, and is common for fireman’s blankets, home decor products, and industrial fabrics. Wool fibers are self-extinguishing when exposed to flame. The high absorption rate keeps wool from conducting electricity. This property also makes wool act like a magnet to prevent fine dirt and dust mites from moving deep into the fabric.

Because of wool’s diversity, you could probably knit with a different type of wool every day of the year. For its variety and exceptional properties, wool is the most popular fiber to knit with. I have garments made from wool that have lasted for years, and I still pull them out season after season. I don’t know any knitter who hasn’t worked with the many wool options available. But if you’re new to knitting and haven’t worked with this amazing fiber, give wool a try; enjoy its qualities and the feel of the yarn as it moves across your needles. You won’t be disappointed.

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