The difference between Woolen spun and Worsted spun yarn

Woolen spun versus worsted spun. You've heard the terms, but maybe you didn't understand why they matter. This blogpost will explain what they mean and also explain how the differences affect your knitting as you work with them.

There are two different ways to construct a yarn when you are spinning it; woolen spun and worsted spun. Most yarns are worsted spun. In this spinning method, the fibers are combed straight before spinning. This means all the fibers are laying nice and straight alongside each other as they are twisted into their final yarn form. In contrast, the fibers are not combed straight before spinning a woolen spun yarn. The fibers left all jumbled and tangled inside the yarn as it is spun, which leaves a myriad of little air pockets in the yarn.

Woolen Spun Yarns

Because they have not been combed, woolen spun yarns are much less dense as there are a lot of little spaces between the jumbled fibers. These little spaces are full of air, which makes the woolen spun yarn lightweight and airy while also increasing the insulating ability of the yarn. All those little pockets of air help hold warmth close to your body.

The fabric created by a woolen spun yarn is going to be very lightweight and warm. Usually, the fabric created by a woolen spun yarn has a bit less drape as compared to a worsted spun yarn, but this isn’t a hard and fast rule. If you want a super cozy sweater that doesn’t weight a gazillion pounds, look for a woolen spun yarn. It’ll keep you warm without needing a lot of heft to get the job done.

One of the most wonderful things about a woolen spun yarn is how the stitches behave when they are blocked. During a warm bath, the stitches will puff up a bit and bloom. Because the fibers are not combed straight and held into place by the twist, the fibers have the ability to expand a bit and incorporate even more air into the fabric. As they bloom during blocking, the stitches tend to expand widthwise and shorten a bit lengthwise.

The way a woolen spun yarn blooms upon being blocked makes it incredibly well suited to colorwork. As each stitch expands widthwise, they push into each other and close up any of the little gaps between the stitches. This gives you an entirely cohesive colorwork fabric. You won’t be able to easily distinguish between one stitch of one color and one stitch of another color. It will all just be a lovely knitted painting; blending and melding together perfectly.

The downside to the blooming action of woolen spun yarn does is that you lose stitch definition. This means that if you choose a textured pattern such a cables, the patterning will be a bit blurred. You will still have the texture, but it won’t pop as nicely as it would in a worsted spun yarn. You can still use a woolen spun yarn for textured patterns, and it still does look very nice, just keep in mind that the patterning will be a little bit muted.

The three sweaters shown below are all knit in woolen spun yarns. From the left: Autumn Snowfall, My Fletching, and Silver Birch.

Worsted Spun Yarns

The place where worsted spun yarns really shine is in textured patterns. As the fibers are combed and twisted into the yarn, it removes space for the fibers to bloom when they are blocked. This results in a crisp fabric where each stitch can be clearly seen. Because of this stitch definition, worsted spun yarns are amazing when knitted into textured patterns. Cables and other textures show very vividly and the whole pattern pops quite nicely.

Since the fibers in a worsted spun yarn are combed straight and held tightly in a twist, the fabric is really smooth and can flow nicely around things. This gives it a lot of drape. You can use this to your advantage if you want your boxy sweater to fall nicely down your shoulders or your shawl to gracefully encircle your neck.

While I happily use worsted spun yarns to knit colorwork, you need to know that the stitches will not expand and snuggle into each other like woolen spun stitches do. Your colorwork fabric will clearly show the different color stitches and won’t be quite as cohesive as it would be if it was made with a woolen spun yarn. However, of all the attributes of a worsted spun yarn, I think this one is the least important. Certainly, it is lovely when a woolen spun yarn blooms and creates a cohesive colorwork fabric, but worsted spun yarns also create beautiful colorwork as well.

The three sweaters shown below are all knit in worsted spun yarns. From the left: Blizzard, Borealis, and Jane.

How it affects your gauge

Because woolen spun yarns bloom more during their first bath than worsted spun yarns do, you will end up with differences in gauge between the two constructions, particularly row gauge. A woolen spun yarn will have fewer rows per inch / cm than a worsted spun yarn will have even if they are the same weight (dk, worsted, etc) and have the same stitch gauge. This is because the stitches in a woolen spun yarn like to expand sideways when they are blocked. As knitting expands from side to side, it shrinks lengthwise. Those fluffy woolen spun stitches are shorter than their worsted spun counterparts.

When you are choosing a yarn for a pattern, look at the whether the yarn used in the sample is worsted spun or woolen spun. If the designer used a woolen spun yarn, and you are choosing a worsted spun yarn (or vice versa), you will struggle to match row gauge. 

Not being able to perfectly match row gauge usually is not a deal breaker when knitting. Most patterns, including all of mine, list the measurements to knit something to. If you can knit to a measurement instead of a number of rows, you’ll be ok when your row gauge doesn’t match the pattern. Just keep the row gauge issue in mind when you are choosing your yarn and knitting your gauge swatch.

Which one is more durable

The durability of a yarn is affected by a number of factors including the relative strength of the fiber being used, staple length, number of plies, and tightness of the spin itself. There is no clear winner between woolen spun versus worsted spun when it comes to the durability and longevity of the yarn.

I’ve had a sweater knit with a woolen spun yarn last for years with little visible wear. I’ve also had a sweater knit with a woolen spun yarn fall apart after one year of wear. The same holds true for worsted spun yarns.

Durability is a whole other topic too deep to go into here, and we will get into it some other time.

When to use which

 There are some general rules for when to use each type of yarn, but you should consider them gentle guidelines rather than hard and fast rules that must be strictly adhered to. When you understand how the different types of yarn behave, you can better choose the yarn that will give you the end result you want. This will also help you to understand why your sweater looked different than the designer’s sample or some podcaster’s sweater because you knitted yours in a different type of yarn.

When should you use which yarn?

For colorwork: woolen spun

For texture (cables, knit / purl textures, etc): worsted spun

For airy warmth: woolen spun

For drape: worsted spun

As I said before, keep these in mind as gentle guidelines. My most recently finished sweater is a colorwork yoke knit in a worsted spun yarn, and I’ve knitted two cabled and textured sweaters in a woolen spun yarn. Just expect your colorwork fabric to be a less cohesive when using a worsted spun yarn, and your cables to be softer and a bit muted when using a woolen spun yarn.

Now that you understand yarn a little bit deeper, you can choose an even more perfect yarn for your next project!