Last week you made it through my blog post of how to choose the right weight yarn for your next sweater. This week let's look at the kind of fiber you choose. When we get to talking about fibers I have two things to consider:
1.) How soft do I want my yarn?
2) How durable do I want my yarn?
Some of you might be thinking, "Danie, I want it super soft and super durable, duh!" Trust me, I want that too. Generally speaking though, the softer a fiber the less durable it will be and the more it will pill. Why is that? For the best in depth explanation, I really suggest you watch Know Your Wool with Deborah Robson. It is a free class on Craftsy and it will make you think about your yarn in a new way as a knitter. Deborah is a co-author of The Fleece and Fiber Sourcebook and not only knows her stuff but knows how to explain it to you.
Although a softer yarn is usually more prone to pilling, that doesn't mean you have to give up a soft Merino. If you blend a Merino with Nylon or silk, it will wear better. The more plies your yarn has, the stronger it will be and the more resistant to pills. A tight ply will also give you a more durable yarn. So if you are wanting a very soft sweater, don't give up hope! Look for a blend that will strengthen it, a 3 ply or more and a tight ply.
While I won't be going into the different breed specific fibers (that's a great post post for those of you spinning your own sweater yarn, but a whole book has been written about that (see above my friend)), I can use a few examples of bases from One Twisted Tree to explain different things to look for. In order to choose a base you need to know what you want from your sweater. The easiest way to explain is to show you my bases and tell you about the types of sweater it will make. While I'm using my own bases to explain, you can use this information when purchasing yarn from anyone.
Prime: (75% Superwash Merino, 25% Nylon; 4 ply fingering weight)
This yarn is the little black dress of bases. It can knit up as a great pair of durable socks or a beautifully drapey shawl. The Merino makes a very soft and smooth fabric while the Nylon adds a bit of strength and durabilty to the fabric. This yarn is plied tightly, there are no soft pillows of ply. It is a tight and smoothly plied yarn that also helps with durabilty. This yarn will give you a fabric that drapes wonderfully. I would use this base to knit a sweater that I planned to wear a lot like a cardigan (that gets a lot of wear because it needs less washing when you throw it over a shirt), a pullover sweater, and I would use this yarn in a sweater that I wanted to wear next to my skin.
BFL Prime: (75% Superwash BFL, 25% Nylon; 4 ply fingering weight)
This base is very similar to the Prime base except that it is BFL instead of Merino, but it is a very different yarn. While the yarn is plied in the same manner for a tight and smooth ply that helps with durability, the BFL gives you a very different fabric. If you feel the yarn in the skein, they are pretty similar in feel. If you look at the yarn structure, they are very similiar. If you knit up the BFL, you will feel something very different than the Merino Prime. The BFL is bouncier and crunchier. It might have a bit of a scratch to it, but I find not much. I am knitting my Sugared Violets shawl out of this base and find that it gives a life to the shawl that it would not have had in Merino. If you are looking to knit a sweater in BFL you will find that it is slightly scratchier than the Merino, your sweater will have bounce and spring, and it will be more durable than the Merino. This makes it great for a cardigan (both because it is durable enough to stand up to hard wear and because any scratchiness you find would be minimized worn over a shirt). If you were planning a sweater out of it, I would knit a swatch, wash it, and then pin it to the inside of your shirt for a day to see if it bothers you. I have VERY sensitive skin so I would certainly try that test before setting out on a whole sweater.
Lavish: (100% Superwash Merino, 8 ply heavy sport/light DK weight)
You already know that sport/DK is my preferred weight for my sweaters (thought that doesn't mean it is for you). I chose this base because I thought it would make a great sweater. It is soft Merino, but this yarn is constructed with 8 tight plies that adds a lot of durability to the finished fabric. With all of those plies, this is a very round yarn which gives you great stitch definition for textured patterns and cables. I knit my latest Mama Vertebrae cardigan in this base and wear it all the time (even in these summer months because I'm always cold). It wears very well. I would use this yarn for a hard wearing cardigan, a squishy soft pullover, and is a joy to wear it next to my skin.
In order to choose a yarn for you sweater based on construction, you need to know what kind of sweater you want in the end. Are you looking for a soft yarn to wear next to your skin? If softness is a priority, then try to pair common soft fibers like Merino with durable features like Nylon or a tight ply to combat pilling. If you want a drapey fabric, then a smooth fiber like Merino is great, but if you want something with a little life to it then a fiber with more crimp like BFL is just the ticket. If your goal is an outerwear cardigan, then look for something durable like BFL or a yarn with a tight twist and a lot of plies
Planning on cables or textured patterning? Stick to a yarn with at least 3 plies which makes a round yarn that will help make the pattern pop out. In fact, when knitting a sweater, I (personally) wouldn't knit with anything less than a 3 ply if durability were a priority. Of course, for your particular sweater, durability may not be. Your goal could be a soft and light cardigan to put over a dress just to keep the chill of summer off of your arms. In that case, a 2 ply is just what you need. If you are looking for a sweater to keep you warm over the winter, it will usually get more wear and a 3 ply or more is a better choice.
Now go forth and search Ravelry for you next sweater knowing that you are better equipped to decide on your sweater yarn purchase.