Choosing yarn is hard for me. I don’t know about you, but I generally go into “choice paralysis” the minute I hit a yarn store, a craft store, or the internet. The days when you could choose a yarn by “weight” because everything was either wool or acrylic are long, long over– there’s so many different yarns, with so many different properties! So how do you pick?
After four years of yarn shopping and lots of mistakes, I have my yarn-shopping criteria whittled down to six dimensions. I start with the dimensional criteria that will eliminate the largest possible amount of yarns and work my way down. This way, we can get down to a manageable number of options quickly and efficiently. I would order them by importance, but as it happens I think all the dimensions are equally important.
Nota bene 1: These dimensions only work if you already know what you’re buying yarn for. The yarn you’d buy for a winter sweater will fall differently on the dimensions than a yarn you’d buy for an afghan, or even a spring sweater. So pick your project, decide when and how and how often you plan to use your finished object, and then refer to the criteria below to pick your yarn.
Nota bene 2: This isn’t a lesson on gauge, and I won’t be discussing the effects of the size of needles you choose on the properties described here. Suffice it to say that if you choose a needle size highly different from the size recommended by the yarn you choose, don’t come crying to me if your carefully-chosen yarn doesn’t behave the way these criteria say it should. If you bash in your TV with a wrench, no amount of instructions for how to change the channel will help you.
In order of consideration:
Back in the day, yarn weight, or thickness, was the only criterion that mattered to most people. Weights range from polar (knit on size 15 US needles) to cobweb (think sewing thread). (For a summary of the various yarn thicknesses, go to YarnStandards.com. What does thickness mean for your project?
Thicker yarn means knitting goes faster. If you’re an impatient knitter, you’ve probably already learned to choose thicker yarns because you have to knit fewer stitches and fewer rows to finish a project. Conversely, if you’re trying to save money on your knitting habit, knitting objects with a thinner yarn makes projects last longer, thus decreasing your $$s spent per hour knitting.
Thicker yarn means fewer stitches and rows in a project. Yes, I said that already, but this time I mean something different. Thicker yarns mean that any motifs, from lace to cables to texture work, are larger, but there will be fewer repeats of them. It’s very hard to get delicate, detailed effects in thick yarns. For example, contrast the Vihervaara sweater, from the Fall 2008 Vogue Knitting (in bronze), and Morrigan, from No Sheep for You (in blue). Vihervaara is knit in bulky-weight yarn, while Morrigan is knit using DK-weight yarn (though the very small needles used mean the final gauge is closer to what you’d typically get with a fingering-weight yarn). Vihervaara is defined by one repetition of the swirling cable motif, while Morrigan is covered in tiny cable panels, each a different pattern. If you tried to knit the Morrigan charts using bulky yarn, you’d end up with a sweater large enough to hold three or four of yourself! So if you have multiple motifs that you want to use, or if you have one chart that’s very, very big (100 stitches across by 200 stitches high, for instance), make sure to choose a yarn thin enough to accomodate all your patterning. In contrast, if you have just one motif that you’re crazy about, a bulky yarn will make a bold statement.
Fabric knit from thicker yarns will be thicker. This may seem obvious, but it’s surprising how often people forget that knitted stitches are three-dimensional. Because knitting involves passing loops over other loops, your final knitted fabric will be a little more than twice as thick as the circumference of your yarns, since each loop-pass-over means you have two pieces of yarn lying on top of each other, with a bit of space in-between. Thick fabric is warmer, but tends to add visual pounds, since you’re essentially making your entire body that much thicker by putting on the garment– even if it’s skin-tight. This can be the big shocker for people new to knitted garments, since most machine-produced garments are thin enough that the extra width they provide can be ignored.
Fabric knit from thicker yarns will be less stretchy and less flexible. The movement, or drape and give, of knitted fabric comes from the tiny loops of yarn moving against one another, pulling slack from one set of loops to give it to another set that is under stress. Since thicker yarn means fewer stitches, it also means fewer loops to share out slack when the fabric needs to stretch or bend. Imagine a 3-foot-long chain made of metal loops. If the chain is made of three loops, each a foot long, there’s only so many ways you can bend the chain. If the chain is made of 36 loops, each 1 inch long, the chain becomes a lot more flexible. Generally speaking, garments worn next to the skin want a lot of flexibility, because they move whenever you do. Outerwear or objects can be less flexible, since they move less.
Fabric knit from thicker yarns will weigh more, since it takes up the same space in two dimensions, plus increased width in the third dimension (as mentioned before). This matters more for some fibers than others, as we’ll discuss more in the Density section. In general, heavier fabric tends to stretch more when used: blankets will stretch out all over, garments will stretch vertically as gravity pulls them, etc. Though again, this is also a matter of density.
Mistakes are harder to hide with thick yarns. Since each individual stitch is bigger, each mistake you make will be bigger and harder to hide. On the other hand, because the stitches are bigger, it’s also much easier to catch mistakes and fix them as you go.
Holes are bigger in thick yarns. This means lace holes will be bigger, and also the gaps between stitches when the knitting stretches will be bigger. So thick sweaters that are too tight across the bust often show “white” across the bust areas, as the stretched fabric shows the t-shirt (or bra) underneath. This is a risk in all knitting, but thinner yarns mean smaller holes and less to show through. This problem often shows up most sharply in photos lit by flash.
Individual increases and decreases have a larger effect in thick yarns. After all, if your yarn is thicker, the impact of removing or adding a stitch becomes much greater than in a thin yarn. As a result, increase or decrease slopes tend to be much sharper.
Additional comments or reflections on yarn weight/thickness always welcome!