A Good Yarn?

I love Ravelry (oh, did I mention that already?), and one of the things I love about it is the wealth of experience it contains.  I'm starting to learn (the hard way) that I should look at yarn reviews and project comments. Comments on yarns can be very revealing. I sincerely hope that the yarn producers read them and act accordingly. Free, relatively unbiased feedback, for which you don't have to do market research? These reviews are a gift!

A few months ago, I was browsing through the DK and Aran weight yarns hoping to find some which I can afford and don't have too many drawbacks, in order to do a couple of cabled sweaters, major projects after all of last year's socks!

Naturally, the yarn brand's own description is unlikely to reveal some of the downsides of a yarn and you may need to read between the lines of the description. Wonderful for felt? It probably felts very easily. Superwash wool? Is it, though? Plenty of people have experience which may say otherwise, even when they carefully follow the care instructions. Good stitch definition - does it keep it after washing?

On the other hand, many of the yarns have quite high star ratings from users and have been used in hundreds or thousands of projects, but have relatively few pages of users' comments, which tend to reveal the real issues. I found myself wondering what that was about. Of course, it's easier just to click the rating than put your thoughts together and write a comment.  It could be that users don't think to go back to comment once they've discovered issues such as the dye running, or growing after washing. Or perhaps when they do, it's all been said already and they don't think they can add anything, so they don't. Yarn comments are often included in project comments.

It's tempting to rely on the old maxim that you get what you pay for, but this isn't necessarily true. I saw a review for a mid-range to expensive yarn from a textile student who was creating a garment as an examination piece, and finding terrible problems with the yarn fuzzing and pilling, almost starting to friction felt, during knitting. She contacted the brand's helpline and it turned out they knew about the issues, and advised that she try to knit holding it well away from herself and with the stitches separated! (For the non-knitting reader, this is not a practical solution!) The yarn has since been discontinued.

Yarn quality is important. If you were spinning and dyeing the yarn yourself, you might be happy that you've produced something and take a relaxed view that 'it is what it is'. With experience, you may then improve the quality of your handspun and dyed yarn. We expect yarn producers to have that experience already and to manage quality issues as part of the production. Of course, commercially manufactured yarns and the resulting items, such as sweaters, may have quality problems too, such as the dye crocking or running and ruining the Fairisle pattern of the jumper and the blouse you were wearing under it, or a 'Superwash' sweater which shrinks and felts on the first wash. If that happens, you take it back to the shop. If the same thing happens after you've shelled out your hard-earned cash for yarn and spent many hours creating your knitwear, then all you can do is complain to the yarn producer, comment on Ravelry to warn others, and have a cup of tea while you curse and sob your heart out in anger and frustration over the wasted money, time and effort.

'Known' Characteristics
Some characteristics may be normal for certain yarns, but an unacceptable feature and a sign of poor quality in others.  For example, mohair yarns are naturally hairy and grippy, so stitches are hard to unravel and textured stitches will be hard to see. Apparently, alpaca is known for showing up uneven stitches, and paradoxically having poor stitch definition. Merino often grows on washing and pills when knitted too loosely. Singles (yarns which aren't plied, that is, more than one yarn twisted together), at any weight, may pull apart or snap if your tension is too tight. Nylon can feel quite harsh. Tweed yarns contain neps. Thick and thin yarns are deliberately thick and thin.

I saw someone complain that her wool-rich jumper smelled of wet sheep when washed! I suppose the smell of wet sheep isn't for everyone, but I would be disappointed if my wool-rich garment didn't smell of wet sheep when I washed it! I also had a look for comments on a very popular acrylic yarn, to find that no-one had anything to say, good or bad, although it had a reasonably high rating. Perhaps it's because it is so completely as expected.

Yarn Texture
Sheddy, linty: Hairs or bits of yarn drop/fly off while knitting or wearing the garment, leaving you and the area where you've been sitting covered in bits
Fuzzy: Some apparently smooth yarns develop a fuzzy 'halo' or 'haze', either after washing, or while they are being knitted. This can be a precursor to pilling and may make a garment look more worn or old than it is. Fuzzy, hairy yarns don't make for good stitch definition.
Grippy, sticky: Sticks to itself, may also stick to the needles (depending on their material - plastic and wood can have issues), difficult to frog/unravel or tink/correct stitches. This can work for you if, say, you are an accurate knitter creating a sweater with steeked armholes.
Pilling is a very common issue. It happens when short, loose fibre ends on the surface of the fabric form small bobbles. Wool, cotton, acrylic, polyester and nylon tend to pill the most, with knitted fabrics pilling more than woven ones and loosely knitted fabrics more than tightly knitted. If you are working with a yarn which is known to pill badly, it's worth working out gauge and size to allow you to work on smaller needles. Wool pills tend to break away from the fabric and fall off, but pills on synthetics will need to be shaved off to keep the garment looking good.
Friction felting: Some yarns may start to felt while they are being worked, and the soles of socks may felt from the friction of being worn. 
Splitty: Especially in loosely plied yarns, where the plies unravel enough that you leave part of a stitch behind while knitting. If you pick up and adjust the leftover loop and it settles back with the other plies, no problem. However, some splitty yarns are unforgiving and the loop cannot be persuaded to rejoin the main yarn, leaving a snag. If you are working with a splitty yarn, sometimes it's worth changing your needles for ones which are less sharply pointed, and working more carefully.
Snaggy: Also in loosely plied yarns, or where two yarn types are plied together, such as a metallic thread or a binder thread with sequins. One of the yarn types may catch on things more than the other, leaving snags and pulls, which very quickly make the item look old and tatty.
Coarse, harsh, wiry, crisp, stiff:  Different colours of the same yarn may be coarser than others, due to the way that the dyes react with the fibres. Depending on the reason, this is sometimes resolved by washing and a rinse with fabric conditioner. If there appear to be no problems with the yarn/fabric growing on washing, pilling and snagging, it might be possible to work at a looser tension. However, very coarse yarns can be a literal pain to work with. I used to crochet doormats from recycled baler twine and have yet to find anything coarser than that!
Itchy, scratchy: This generally depends on how sensitive you are to the fibre types in a yarn. It's also a good idea to wash new garments to remove any lingering factory finish which may cause irritation. Even so, some yarns seem to be itchier than others. The scratchiest thing I have is a shop-bought shrug/wrap cardigan, made from a chunky-weight synthetic ribbon yarn plied with a sequinned thread binder. The sequins stick in at all angles - definitely not as comfortable as it looks.

Dye problems
Excess dye
Colour runs in wash:  There is often a bit of excess dye when it comes to natural fibres, either pure or blends, so always wash dark and saturated colours on their own, at least for the first time. You can try a dye catcher sheet or colour run remover for unexpected disasters, but it's worth knowing if the colour runs and taking steps to fix it as repeated running can lead to fading.
Crocking is a worse problem, because the dye starts to come off the yarn with friction or the smallest amount of moisture. You can often pick this up while knitting, as you realise your fingers and even the needles are a picking up the colour where you tension the yarn or hold the fabric.This also has the potential to ruin your clothes.
If you don't want to or can't return the yarn, you can try fixing the dye.
For cotton, linen and viscose, soak the yarn (you need to unwind it into skeins/hanks first) or the finished item in water in which salt has been dissolved (weigh your item dry first and use its weight in salt, with easily enough water to submerge the yarn). Use white vinegar in water for wools and silks (protein fibres). It's difficult to give proportions. I've seen advice which varies between a 'glug' and a cupful per bowl or (stainless steel) pot. It may be worth treating it as if you are dyeing the yarn; here's a good article from Knitty.
Having soaked the yarn, wash separately to try to get rid of any excess dye before knitting the yarn up (or wearing, if it's a piece which has already been knitted). Be careful of wearing the piece with other items of clothing which will show any transfer.
Colour fading: It's no accident that 'vintage' fabrics look slightly bleached or faded, with muted colours. Exposure to UV light (and oxygen) causes most dyes to fade, (some, such as reactive dyes on cotton, linen and viscose, faster than others). By the time the fading has happened, there's nothing you can do about it. So move that richly coloured cushion out of the sun, and don't place or hang items to dry in bright sunlight.
Unexpected colour variation within a ball: If it's a solid colour, this usually indicates something was wrong during the dyeing process. If it's a kettle dyed or hand painted yarn, then it's likely that the dye didn't penetrate a section of the yarn. Some self-striping or self-patterning yarns have knots (or, if you're lucky, splices) with abrupt colour changes either side of the knot or splice.
Colour variation within a dye lot: You don't expect it, but you do see it. Not good, yarn producers, not good at all! The best fix  I've seen, from someone who couldn't get a solution through their yarn supplier, was to buy more and use the variation in shades to create a subtle Fairisle pattern.

Spinning, plying and winding issues
You wouldn't think this would be a problem with commercially-produced yarns, but it reflects poor quality control.

The fibre may not have been cleaned very well, so that there are still bits of vegetable matter (VM) in the yarn. I've also found bits of plastic and nylon in some cheap yarn, and unwanted neps (small lumps of short fibres, sometimes in a different colour - normal in a tweed yarn, but a bit annoying in a fine sock yarn!)

An uneven spin/ply can lead to variations in the yarn weight, so that it is (unintentionally) thick and thin and there may be unplied sections in a plied yarn. Alternatively, the yarn may be spun (overspun) or plied so tightly that yarn twists into loops and tangles.

Overspun yarns and thin sections may result in breaks or yarn ends within the ball . Where these are found, and presumably also where thin, tangled, frayed or stained sections are found in quality control, the ends may be knotted together so that you get knots in the ball. I've seen a couple of comments to the effect that a couple of knots in a 100g ball is pretty much industry-standard for acceptable quality, so if you get a ball without knots, you're lucky. That said, most of the balls of yarn I've knitted so far have not had knots, but my experience isn't so very extensive!

I've seen some reviews of mixed-fibre recycled yarns, especially those containing silk, where the yarn pulls apart quite easily. I'm all for reusing rags, but some of these yarns seem quite expensive to me, so I would definitely read the reviews before buying!

The yardage/metrage is often stated as a rough guide, but you would expect the ball weight to be accurate. However, it can be out by as much as 10% (although it's rarely over; I've had quite a few 100g balls which have been 98g). I've also seen a review for a yarn stating that the length was incorrect - I can't imagine actually measuring a whole ball or skein of yarn, but it strikes me that you would have to keep the yarn at a constant tension to get an accurate result.

And last, but not least, loosely wound balls which fall apart, leaving a tangled heap of yarn.Try not to pull, as it might knot itself tighter. And keep away from playful cats!

Washability
During processing and winding into skeins, balls or cones, the yarn fibres may be stretched, compacted or have some residual oil or finish, so that the yarn can feel quite different after its first wash.
Growing, stretching is where the yarn stretches and relaxes. Especially a problem for loosely knitted, heavy items. If the maker's suggested gauge seems tight and the yarn is known to grow on washing, go for the tighter gauge.
Shrinking is a common problem with wool.
Blooming is where the yarn seems to swell or puff a little and have a slight halo after washing, and the fabric seems to get a little wider and shorter. It's not really a problem, as the fabric often feels and looks softer, although you may need to pull the garment back into shape or re-block and you may loose stitch definition. Finely crimped, downy fibres (e.g. merino, lambswool) often bloom when washed and dried the first time and woollen-spun more than worsted-spun yarn.
Felting in wash. If you want to felt, use hot water, rub and wring the garment to your heart's content and rinse in water at different temperatures. It should be enough that if you don't want felt, use cool-lukewarm water for both washing and rinsing, and handle the garment carefully, avoiding rubbing and friction. Unfortunately, some yarns felt (and shrink) regardless of how careful you are when washing them. And I would like to know why.

Other issues to look for are stitch definition (possibly related to how crisp or soft a yarn is) and how well the yarn/item holds its shape after blocking (heavy, soft, loosely knit items may not hold their shape).

Finally, the same yarn may change in quality or characteristics over time, maybe because the producer has made changes, so it is worth giving and reading recent feedback, as well as older comments.

There are fixes for some of the quality issues, but you may not think to do it, and why should you, when you've just paid for a yarn which you expect to be of reasonable quality?  This is where creating a swatch can be so useful and important. Not only do you check your gauge (number of stitches and rows over 10 cm/4"), but you can wash it to check for dye loss, dry it and block it to check for growth/shrinkage, felting, and other quality issues, and make notes for posterity in your design book and on Ravelry, so others can benefit from your research! If you're planning a very large project, you might want to buy only a test ball before buying all the yarn you need (in the same dye lot, of course!).

After I'd written this, I belatedly wondered what else was out there about yarn quality.  I found this post by knittingharpy, who strangely didn't mention Ravelry but pointed to other sources of information on the Knitter's Review and on WiseNeedle. The latter has been taken down, having become uneconomic in the face of competition from Ravelry. It contained reviews since 1995, and it's probably a vain hope that the information has somehow found its way onto Ravelry. The owner, String or Nothing, has a good reference section.