When I started knitting, I didn't know about local yarn shops and all the vast world of yarn selection. This was just before Ravelry started, and I learned a lot on the forums at knittinghelp.com. People were talking about this amazing yarn, which they called Mmmmmmmmmalalabrigo. That's Malabrigo, in case you didn't catch that. And it was a yummy yarn indeed. That was when Malabrigo had only one base, the base now called Malabrigo Merino Worsted. It's a singles yarn and oh so soft. So so soft! It was my first non-acrylic yarn, and I have to say that it spoiled me.
Once I tried Malabrigo, I didn't look back, and I started using it for everything I was making. If a pattern called for worsted weight yarn, I knew right away which yarn I'd be using! My only decision was on color. And when my LYS started carrying the yarn, my knitting world was complete!
My first cabled scarf? Malabrigo of course! Tons of hats. Some fingerless mitts and full mittens. Even some felted projects. (I do remember the first time I felted Malabrigo and wondering why on earth I was felting this magnificent yarn!) I was playing D&D during that time, and my dice were treated to the Malabrigo experience when I made a dice bag out of it. (My dice still live in that bag!) Shawls and cowls and even two little cardigans for my son when he was a baby. Everything was made out of Malabrigo Merino Worsted.
I even made garments. Some I finished and some I frogged. I looked back at my project pages on Ravelry and found a cardigan I had started with Malabrigo. In the notes, I read this: "Although I love the yarn, I’m wondering if this is truly the right project for it." And almost two weeks later, I updated to say this: "I’m reclaiming my Vaa [that's the color name]. This project just isn’t what I want to do with it." That project was over 10 years ago, so I don't remember exactly why the yarn didn't feel right for that project, but knowing more about yarn now, I think I know. It's because it was a singles* yarn.
What's so wrong with making a garment out of a singles yarn?
When multiple strands of yarn are twisted together, some of the yarn surface is protected by being in contact with the yarn surface of another strand next to it. The more plies you have, the more protection for each individual ply. With a singles yarn, that strand is all on its own, without anything nearby to offer protection. That means the surface of that one strand takes all the wear rather than the wear being spread out to multiple strands of yarn. There’s no hiding for any surface on the singles yarn.
And when you have a fiber such as merino or cashmere that is short stapled (meaning the individual fibers being twisted together are short), there are a lot of fiber ends that need to be held in by the twist. With all surfaces of that singles strand of yarn being available for wear, there’s more opportunity for those fiber ends to start lifting up from the surface. And that’s what creates pills. Add some friction, lift up those fiber ends which then rub together, and that creates a felting effect which leads to those tiny balls you’ll find on your project. And pills make the item look worn out. For something that you want to look nice, such as a fancy sweater, you don’t want those pills all over the sweater. Yes, you can pick/shave them off, but that is ultimately removing some of the fiber and thus the structure of the yarn. And over time, it can cause holes in the fabric. (And the places that receive the most friction will show the most pilling, for example, under your arms.) Better to choose a yarn with more structure (plies) to help keep the pills down. (Note: more plies does not mean no pilling, it just means less pilling.)
To make yarn, twist is added to fiber. That’s what holds the fibers together. Adding twist is going to add something called bias, which means if you knit a square stockinette swatch, it’s possible that because of the energy in the twist of the yarn, that square swatch might have sides that are slanted rather than straight. When you take two strands of yarn that have been twisted and then twist them together in the other direction (ply), then you are balancing that twist energy and the square swatch is more likely to come out with straight sides. For a singles yarn, that balance through plying doesn’t happen. Depending on how much twist is in that singles yarn, you may find some biasing or slanting in your project. Much of that can be fixed through blocking, but you’ll want to watch for that. You can also fix the bias by choosing stitch patterns that combine knits and purls, which helps to even out that twist energy. You can also use a smaller needle to create a tighter fabric, which helps to hold that twist energy in check.
What is it good for?
I don’t want your takeaway from this to be that you should avoid singles yarn. Far from it! What I do want you to understand is how to pick the right project for a singles yarn. Skip the cardigan that you plan to wear all the time. But go ahead and use singles yarn for a cowl; the softness from the yarn around your neck will feel wonderful. And cowls usually don’t have heavy friction spots (it’s possible, depending on how you wear them and if your jacket/coat rubs against the cowl to cause friction but it’s less likely). The same goes for hats.
Or take the tendency of a singles yarn to pill and slightly felt (or really felt if not superwash) and use that to your advantage. Make mittens/gloves with a non-superwash singles yarn if you’re in a cold environment. As you wear the mittens, particularly if you’re touching snow and the mittens are getting damp, you’ll be creating a lot of friction, which will cause the mittens to felt. But don’t worry, it’s not enough friction to cause them to shrink a ton (though there may be some shrinking). Instead, the stitches next to each other will start grabbing on a little tighter to one another, pulling together and interlocking. And now, that cold air or snow will have less chance to get to your skin, keeping you that much warmer.
I do hope you explore using singles yarns in projects where the softness will be an advantage and the durability doesn't need to be a key factor.
*Note: You'll often hear this yarn described as a single-ply yarn; however, that term is not accurate. There's just one strand there, so nothing has been plied together; hence, it's not a plied yarn and shouldn't have ply in the name. So "singles yarn" is a more accurate term, but it's the same thing people mean when they say "single-ply."
Here's my Vine Yoke Cardigan (designed by Ysolda Teague) made from the singles yarn from Malabrigo. I only wore it once and already the fuzziness is happening and pills have started forming; the closeup is along the hemline at the bottom. I didn't want the cardigan to continue pilling so it's just been sitting in my closet for the past ten years.