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Decisions, Decisions: How to Choose the Right Yarn for Your Sweater

January 14, 2021

Choosing yarn for a sweater can be a big decision. You may be working with this yarn for a hundred hours or more – and wearing the sweater you make even longer. Sweaters are usually the largest items knitters make, and the cost for that amount of yarn can be high. So how do you choose a yarn that’s right for you?

The most important thing

Some folks will tell you that you have to choose a certain type of yarn for sweaters. They will tell you it has to be hard-wearing yarn, that is has to be exactly the yarn suggested in the pattern, or that it must match the colours you already have in your wardrobe. But here at Tin Can Knits, we are not purists. For us, the most important thing about a sweater yarn is that YOU love it. What good is knitting a whole sweater in a yarn you aren’t thrilled-to-death about? Are you suddenly going to become enamoured with a yarn you find scratchy or dull once it’s knit into a whole sweater? I doubt it. I personally like to wear black quite a bit, but I definitely don’t want to knit a whole black sweater! So forget what you think you SHOULD use. Go out and find a sweater yarn that is perfect for YOU.

smiling woman in a green and teal handspun sweater
Emily’s current favourite yarn is her very own handspun. This beautiful Flax sweater was Emily’s first garment in yarn she spun herself.
Blog post Alexa's Sweaters in Review
My current favourite sweater is my Cartography sweater that I knit with Spincycle Dream State and Stone Wool Cormo. It is light, soft, and warm, and I really enjoyed the subtle colour shifts of the Spincycle.

It’s all about pros and cons

Not all yarns are great for sweater knitting. A single-ply, un-spun yarn, for example, will likely end up a pilly mess after only a few wears. There are lots of different types of yarn out there, though, and they each have their pros and cons. We stand confidently behind the yarns we use for our pattern samples, but we know they aren’t always available or accessible to everyone – nor are they necessarily what you might choose for your own sweater.

And just because WE have used a certain type of yarn for a particular sweater, it doesn’t mean that is the ONLY type of yarn that will work. A sweater knit in a single ply and a plied yarn might look different, but it certainly doesn’t mean one is definitively better than the other. It comes down to what YOU prefer for YOUR sweater. Customizing things to suit our tastes is what knitters do, after all! Keeping that in mind, here are some factors to consider when choosing a sweater yarn.

Construction or ply

What is a ply? A ply is a strand of fibre that makes up a yarn. A single-ply yarn is just one twisted piece of fibre. A plied yarn is composed of two or more of those plies twisted together. A two-ply yarn is made up of two single strands. A three-ply yarn is made up of three single strands and so forth. Take a look at a few of the yarns you have on hand and see if you can pull apart the plies to count them.

If you choose a single-ply yarn for your sweater, it will be oh-so soft and cozy, BUT it won’t be as hard-wearing as one made with a plied yarn. Single-ply yarns also tend to pill more than plied yarns. There are varying degrees of twist in a yarn as well. One that has a lot of twist will last longer, but it generally won’t be as soft as compared to a softer-spun yarn of the same fibre.

Nina is wearing the Almanac sweater knit up in Lopi yarn. It is a single-ply wool yarn that is very warm and quite durable.
Moraine sweater pattern
Hunter is wearing the Moraine sweater knit up in Stone Wool Cormo, a two-ply wool yarn. There is a bit of texture to it when it’s knit up.


There are just so many types of yarns out there these days! You can find yarns made from any number of animal fibres and plant-based fibres, as well as synthetics. There are yarns made from sheep’s wool, alpaca, and yak. There are silk yarns, cotton yarns, and linen yarns. You can also find yarns that are a mix of these things. So which one is right for your sweater?

Emily and I tend to use animal fibres in our sweater knits. Animal fibres have what is called ‘memory’, which means they tend to stay where you put them. They block easily and keep their shape. However, there are exceptions to this. For example, alpaca tends to drape more and holds its shape differently than sheep’s wool. Wool has a few magical properties that I like to take advantage of – like it stays warm when wet and is naturally odour resistant.

3 striped lace swatches
Blocking is a vital part of lace knitting, so if your sweater has lace, you definitely want a blockable fibre. Here, Emily tried a few colour combinations and blocked her swatches for the Chromatic sweater.

Plant fibres, like cotton or linen, tend to keep you cooler. If you live in a warmer climate, they might be the way to go. Plant fibres do not have memory, so they don’t hold their shape the same way that animal fibres do. This can be both a pro and a con. The drape of a linen, for example, can make for a really beautiful top. I’ve had the most success using patterns that are specifically designed for these types of fibres.

The Love Note sweater is knit at a loose gauge. We knit this one in La Bien Aimee single ply, along with a mohair lace. The resulting fabric is light and airy. For more info, check out our post on layering with mohair here.
Hunter is wearing the Antler pullover, knit up in Hinterland Textiles Range, which is a two-ply yarn with a 50/50 mix of alpaca and wool.

Synthetic fibres are the most cost effective when it comes to sweaters. They are also easy to care for; sometimes they can even go in the dryer! You can also often find yarns that are a mix of animal fibres and synthetics, which can strike a great balance.


Another consideration when choosing a sweater yarn is how you will care for your garment. I hand wash all of my hand knit sweaters and my kiddos’ sweaters, too. This isn’t practical for everyone, though, so you might opt for a yarn that is machine washable, like a superwash wool or a synthetic. This is also something to think about if you are doing any gift knitting. In my experience, non-knitters are not always well versed in knitwear care, so keep that in mind.

When I finish a sweater, it gets a bath and a block. For more info on blocking a hand knit sweater, check out our sweater-blocking tutorial here.

The swatch test

So you have your chosen yarn. You have considered longevity, drape, softness, and care, and you have chosen the one YOU love. You are now ready to swatch! Swatching is generally recommended, but I think it is the most important step when preparing to knit a sweater – so don’t skimp on the swatch! Knit a nice big one! We have some thoughts on swatching basics here, the cowl swatch here, and swatching for colourwork here. Give yourself all the information you need before starting your sweater!

Swatching will let you know if you are getting the recommended pattern gauge, and maybe more importantly, if you actually like the fabric at that gauge. Is the fabric is too open or too dense for your liking? Will you want to wear a whole sweater in this colour after all? If you are knitting a cabled sweater, do the cables ‘pop’ the way you want them to? If you are knitting colourwork, do the colours all work together the way you had hoped? Or do you need to add a brighter yellow? Or more contrast? (We have a whole post on choosing yarns for colourwork here.) Your swatch will give you a pretty good idea if your chosen yarn is right for your sweater project.

I knit these three swatches before staring a Bowline sweater. On the left is YOTH Father. Top is Hinterland Range, and bottom right is Stone Wool Cormo. Each yarn had its own pros and cons for that particular sweater, and I had to swatch all three to see which one would work best with the ribbing pattern at the yoke. In the end, I settled on Stone Wool Cormo because I liked the added texture of the tighter spin – and the fact that a cormo yarn would make the sweater light, warm, and soft.
Check out our Week of Colour Hat tutorial for tips on choosing colours for colourwork.

While swatching is important, it is wise to remember that swatches can’t tell you EVERYTHING. A swatch doesn’t have the weight of a whole sweater hanging from it, so it can be a bit more difficult to assess the drape of a fabric. A swatch doesn’t have seams, and it rarely encompasses all of the stitch patterns in a sweater. BUT it is still the best tool we have to test whether or not the chosen yarn will work the way we want it to.

The Hat Swatch

Hats are perfect for swatching, so we knit a whole lotta of swatch hats! For instance, when contemplating the colour palette for the Embers sweater, we first tried several different colour combos in the Embers hat. Yarns in this array include The Farmer’s Daughter Fibers Soka’pii, a single-ply fingering weight; Emily’s handspun, a plied sport weight; and Jamieson & Smith Two-Ply Jumper Weight, a plied wool fingering weight yarn.

What’s next?

You have a yarn you love. You have pinpointed the perfect colour, and you have the right mix of hard-wearing and soft-against-the-skin. Your swatch has told you that the fabric is just right for your liking. Now it’s time to cast on and knit your sweater!

If you are embarking on your very first sweater, or could use some pointers, check out all our sweater knitting tutorials here.

What is your favourite sweater yarn? Let us know in the comments!


14 Comments leave one →
  1. Leonie McKenna permalink
    March 30, 2021 2:44 pm

    Thank you for this information. I purchased Lopi wool online and when I commenced knitting eith it it keep breaking. I tried about six times. I was very disappointed as I had knitted with it many years ago but the wool was purchased in a shop. Can you recommended where to buy quality Lopi wool as I am very interested in the patterns in your article.

  2. January 27, 2021 8:13 am

    I try and spin most of the yarn I knit with. Most times the yarn comes first and then finding a knitting project that’s compatible with the spun yarn. I’m now venturing into “intentional spinning” and trying to spin a specific yarn for a project (first project a Cowichan-style vest). Either way, the journey is the most fun part. I like the suggestion of knitting a hat for swatching a yarn!

  3. Rebecca permalink
    January 18, 2021 2:19 pm

    I mostly use fingering weight for my sweater knitting. I find it to be the most cost effective. Super wash is also really important to me. This is the first winter I have enough knitted sweaters to wear a variety!

  4. Meredith MC permalink
    January 17, 2021 7:01 pm

    Wow, Emily’s hand spun flax is Amazing!!’

  5. Vikki permalink
    January 14, 2021 1:04 pm

    Green Mountain Spinnery Maine Organic- sheepy, great stitch definition, wears really well.

  6. Denise permalink
    January 14, 2021 12:42 pm

    I also try to look at where it is manufactured, too. Where possible I try to purchase Aussie yarn to support our wool industry.

  7. January 14, 2021 8:10 am

    Interesting. I hardly ever consider the wear of the yarn – if I like it I usually just go with it! Yes I have made some mistakes in the past!

    • January 15, 2021 11:36 am

      Haven’t we all!

      • January 16, 2021 10:15 am

        Just done it again. Started a project – love the yarn – not sure I’ll have enough to finish it!!! Was a rash purchase, last of a lot, now discontinued !!!!!!!

  8. Julie Williams permalink
    January 14, 2021 7:55 am

    Your newsletters/blogs are so informative and empowering.

  9. free832612 permalink
    January 14, 2021 7:35 am

    Your patterns arae beautiful.

    Why are the necklines on what is meant to be a warm sweater so low? I would prefer a necklane that is higher.


    • January 27, 2021 8:15 am

      Exactly! That is the most frustrating part of sweater patterns (for me). I can’t stand boatneck anything. Most sweater patterns seem to use this boat neck trend. 🙁

      • Annie permalink
        January 27, 2021 9:00 pm

        I feel the opposite! For me, there are too many high-necked sweaters. They make me feel strangled. OTOH, a cropped sweater seems kind of useless. If it’s cold enough to put on a sweater, I don’t want my middle out in the wind! Lol.
        After you’ve made a few sweaters, you’ll see how to make those mods on your own project. Basically, if it’s top down, cast on fewer stitches and do more increases. Bottom up, keep knitting decrease rounds.

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