What is Wool Yarn Anyway?

Sometimes people use the words “wool” and “yarn” interchangeably.  So what is wool yarn?  And is yarn the same as wool?  Lots to unpack here, so let’s get started with the basics.

What is wool?

Wool is a specialized type of hair.  Almost all mammals grow some type of hair, but very few species grow wool.  The best known of these species; goats, sheep, alpacas, and rabbits, have all been bred by humans to produce better wool.  Wool hair is better at insulating and it likes to stick together.

If you have a dog, you’ve probably noticed that most dogs have two types of hair.  One type is longer, coarser and smoother.  This is your dog’s outer coat, sometimes called guard hair or guard coat.  It’s great for shedding snow and rain, but it doesn’t do a lot to keep your dog warm.  It works the same on other mammals.

The undercoat is shorter, softer, and tends to be fluffier, that is, it has a bit of a crimp to it.  Sheep, goats and rabbits that have been bred for their wool have little or no guard hairs left.  They grow lots and lots of undercoat, also known as a fleece.  In fact, if their undercoat/fleece isn’t routinely removed, or “shorn,” they will develop a variety of health problems and die a slow, painful death.  (Yikes!  Usually this only happens when an animal escapes from the farm or ranch into the wild, perhaps during a wildfire or some other natural disaster.)

wool yarn

Is yarn the same as wool?

No, yarn is not the same as wool, although there are certainly designers who have written as though they are one and the same.  You’ll probably only run across this if you use vintage or older patterns.  Until relatively recently, there weren’t very many choices when it came to yarns for handicrafts like knitting and crochet.

Even if the pattern is vague about the content of the yarn, the yarn label won’t be.  There are national and international standards requiring yarn manufacturers to supply you with complete information on what your yarn is made of, so make sure to read your yarn’s label.

Now, yarn is made from a variety of plant, animal and synthetic fibers.  These fibers are frequently combined with each other, giving yarnists a wide range of blends with somewhat different properties, depending on the combination of fibers types.

Plant, Animal, or Mineral?

Yarn is made from a dizzying array of all of the above these days.  It’s a very good time to be a yarnist!

Of the plant fibers, cotton is probably the best known.  It makes a slippery, heavy yarn, which drapes very differently in the finished product compared to a wool yarn.  Fun fact, cotton is also known as “death cloth” because when it’s wet, it chills the wearer, so please don’t use your cotton yarn, or cotton blends, for winter outdoor wear!

Animal fiber is usually categorized as wool.  If your yarn label simply says wool, without identifying any particular species, it’s very likely to be sheeps’ wool.  Wool sourced from alpacas, camels, and goats will be labelled as “alpaca” or “alpaca wool,” “camel,” or “cashmere,” respectively.

Silk is not considered wool, even though it’s produced by an animal, the silkworm.  Plant, synthetic, and mineral fibers are identified simply as what they are, more or less:  “cotton,”  “nettle,” “nylon,” “bowlder.”

While rare, mineral based yarn fibers do exist.  I have a yarn in my stash that contains “30% bowlder” (seriously), which the manufacturer says is made from jade.  It does have a slightly coarser feel than the average wool yarn, but otherwise, I can’t tell the difference.

While not falling into the plant, animal, or mineral categories, synthetic fibers are widely used by yarn manufacturers.  Since they are human made, they have been engineered to have specific characteristics, but the most common one is that they are cheaper and easier to source than natural fibers.

Synthetic fibers have names like polyamide, nylon, acrylic, etc., and are pretty easy to identify as they sound like something that came from a lab.  They can have just about any texture you can imagine.  Novelty yarns are often made primarily, or exclusively, out of synthetic fibers.

Varieties of Wool Yarn

You can find yarns that are 100% wool, lambs wool, Merino wool, superfine wool, ultrafine wool, and more.  Many of wool’s properties remain the same no matter which wool you use.

Unless they are labelled “superwash” or “washable” wool, all wool yarns should be hand washed in cool water and dried flat.  This is because wool yarns tend to “felt” when subjected to too much agitation, spinning, or even temperature shock.  A felted wool object shrinks a lot and becomes very dense.  This can be a good thing and has been done deliberately over the years to produce very weather resistant garments.

Superwash or washable wool has been treated to prevent felting and can get tossed in the laundry with the rest of your clothing.  It’s great for things that will need to be washed often.

Wool is frequently combined with other fibers.  Wool and cotton are a popular combination, as are wool and many synthetics.  For example, I am currently working with a yarn that is 70% ultrafine Merino wool and 30% bamboo.  I’m not sure what the benefit of combing wool with synthetics is, other than making the yarn cheaper.  Wool and plant fiber yarns are popular for warmer weather knits.

Keep  your finished product in mind when choosing your yarn.  Either choose the same yarn as the pattern recommends, or one that has a very similar fiber make up, or, if you’re knitting without a pattern, choose a yarn that matches the likely activities of the wearer.  Cotton for warm weather, wool for cold weather, etc.


Wool is an extremely popular fiber for making yarn, for knitting, crochet, weaving, and commercial fabrics.  It’s sourced from a limited number of mammals that produce an abundance of a soft, warm hair in the form of a fleece.  This fleece is routinely sheared off the animal and processed into a variety of wool fiber types.

These fibers may be combined with fibers from plants and other sources to produce wool yarn or wool blend yarn.  Combining different fiber types changes some of the properties of the yarn and may determine the usefulness of the your final product.

The word “yarn” doesn’t tell you anything about the fibers that make up a particular yarn.  However, the textile industry is required by national and international laws to tell you what is in your yarn.

Wool fiber, and wool yarn, is a surprisingly big subject.  I think I could write a book on it,  but since this is one blog post, I’ll stop here.  I am planning on writing more about wool in future articles, so please let me know if you have any other questions about wool, yarn, or any other knitting related topic!


Textiles Fiber Composition – Labeling and Identification


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