How to Identify Mystery Yarn

How to identify mystery yarn

We all have them. They are like the Cinderellas of our yarn stash. They are the humble, overlooked balls of yarn waiting to become the beautiful star in our next crafting adventure. We just need to find the shoe pattern that fits them and before we can do that we have to figure out what that ball of yarn actually is.

I’m talking about the balls of mystery yarn you have kicking around in your stash. Let’s figure out what they actually are and then we can figure out what they can be used for and then we you can get around to working them up.


This guide should be pretty handy if what you have turns out to be 290 yds of sport weight in a blend of wool and cotton. If you have something really exotic, then maybe I can’t help you. Back in the midst of time, I somehow acquired a bag of very soft, kind of short, mystery fiber in a a downy grayish brown. No idea what that was or how I came to own it. It just appeared one day in my fiber stash drawer. (That happens to me. Things appear in my stash that I did not put there.) Then I had someone give me a bag of yak down to spin and it was exactly like the mystery fiber that I had been wondering about. I never would have guessed yak down. If that lovely person had not given me more yak, I’d still be wondering about it. So if your mystery yarn is yak or camel or opossum, then we can get your weight and yardage and that its an animal fiber of some kind but that maybe all.

What are the chances your mystery yarn/fiber is yak down? Don’t answer that.

Step 1: What weight is the mystery yarn?

First let’s figure out the weight, the thickness, of your yarn. Disregard that classification of “4ply means fingering”. I’m sure you’ve noticed that plenty of yarn makers sell fingering weight yarn that is not made with four plies. Its an old system that (I think) is based on “standard” thread weight. If you twisted up four strands of the standard thread it would be equivalently thick to fingering weight yarn.

Whatever. That is not very helpful for us today. What is helpful is wraps per inch. Take your mystery yarn and wrap it around a ruler like this:

finding the wraps per inch (wps) for yarn
Finding the wraps per inch for yarn

Don’t pull it tight and don’t leave it loose. Put as much tension on as you do when you stitch and snug the wraps up against each other. Now, how many wraps does it take to cover one inch on your ruler?

Weight Wraps per inch Examples
Bulky less than 6 Cascade 128
Aran 6 to 8 Manos Del Uruguay Clasica
Worsted 9 to 11 Patons Classic Wool
DK 12-15 Berroco Vintage DK
Sport 16 to 19 Lamb’s Pride Superwash Sport
Fingering 20 to 25 Madeline Tosh Sock
Lace 25 or more Malabrigo Lace

If you want to read more about wraps per inch and yarn weights, and its nice to get a second source on a subject, check out the free guide at Craftsy. 

Step 2: How much of this yarn do you have?

Now that we know the thickness of your yarn, we need to know how much of it you have. You are going to need a scale. The more accurate your scale is the better your answer here will be. My scale is… not so accurate. If you have access to a postal scale, like for weighing packages, those are better.

So weigh your yarn in grams and write that number down.

TOTAL WEIGHT = _____________

Next ball up ten grams of your yarn. Weigh it to be sure you have 10 grams.

Now (and this can be a pain) get out a tape measure and figure out how many yards that is.

LENGTH of 10 GRAMS = ____________

Now all you have to is take TOTAL WEIGHT, multiply by LENGTH of 10 GRAMS, divide by 10.



OMG! Did I just tell you to do MATH! On noes! The humanity! Wait. You have a phone right? And that phone has a calculator right? So you don’t really have to do math. Your phone does. Take the first number, multiply by the second number, and divide it all by 10. Now you know how many yards are in your mystery fiber.


Step 3: What is the mystery yarn made from?

In this section we try to figure out what fiber or fibers were used to make your mystery yarn. We want to know if its wool or cotton or acrylic.

The Fleece & Fiber Sourcebook – $21.00The Fleece & Fiber Sourcebook is a must-have reference book for any spinner looking to deepen their fiber knowledge. This book is  truly a one-of-a-kind photographic encyclopedia which fea…

Sniff and Wash

The fastest test you can run is this: Cut off an length of yarn and soak it in hot, really hot water. Then smell it. Does it have a wet-dog-type odor? Then its animal hair of some kind. No matter how much its been cleaned, wool and alpaca will always smell a little when its hot and wet.

If you get an animal smell, then the next step is to figure out is its superwash or not. Take your hot, wet, stinky length of yarn and put it in an old sock, then stick the sock your washing machine with a load of whites and then into the dryer. Open up the sock. If the yarn matted up, its not superwash. It is got battered and fuzzy but is still a single length of yarn, it is superwash.

Shine Some Light

How the yarn look sin teh light can give you some clues. Its not difeinative but it may help.

Animal fibers, regular cotton, linen, and lower quality silk tend to be dull. These fibers don’t reflect light very well. They absorb light (and heat) and will look rough and dark.

Bamboo, tencel, and mercerized cotton will shine, like a reflective mirror.

Higher quality silk will glow almost as if the light is inside the yarn. That’s becasue high quality silk is semi-translucent. It lets light pass through it.

A good quality mohair will shine when you look at it close up but not from far away. Mohair (in yarn not doll hair) has a halo, a fuzziness that dulls the shine.

Acrylic sparkles. In strong light most acrylic fiber will sparkle like grains of sand.

Pull It Apart

Unravel some of your mystery yarn. Keep at it until you have a sample of the raw fibers that were used to spin it. Soak those fibers in luke-warm water and let them air dry. Then put on your reading glasses and take a close look.

Animal fibers usually have some kink. The one exception I can think off is Suri alpaca which is very straight and up to 6 inches long (and usually brown). Otherwise, animal fibers bend, twist, and curl. Do they go mostly in one directions? Can they be lined up to go in one direction? Then its not mohair.

Cotton, linen, bamboo, and silk are straight. Very straight. Ironing board straight.

Acrylics can be anything since they are manufactured but most often they are wavy. And very, very fine. The softer, nicer acrylics are usually made from fibers that have been stretched out to be thinner than wool and then molded to mimic the twist and curl of animal fiber. But the curl is predictable and not random like it with animal fiber. The difference is subtle but you may be able to tell.

Set It On Fire

Okay. Let’s take a moment to discuss safety. You’ll be burning/melting some yarn here and only yarn. Don’t burn or melt yourself. Don’t set fire to your home. Put all curious four legged creatures in the bedroom and shut the door. Lastly, do your pyromaniac thing fire test over a non-combustible surface, like your kitchen sink.

Burn tests are great for figuring out what a mystery fiber is made from. You can have fun with this. Try not to have so much fun that you burn up your stash. But burning small samples are known yarn to see what that does will help you identify your mystery fiber.

Ditzy Prints has put together the most awesome flowchart for your burn tests. I’m not going to put a copy up here becasue that was a lot of work. She deserves all the credit. So I’ll just link it (again) and you can go grab a copy for yourself. (Hint: use the print/save-to-pdf feature from It will let you grab a copy of any web page.)

Then get a candle, or a lighter, and start setting your yarn on fire.

Again, its nice to have a second source of information. Here is a guide from Craftsy on burn-testing fabrics. Its not quite the same as yarn but there is a lot of cross-over of course. They go into more detail on acetates versus rayon and such and you might find that useful.

Dissolve it in Bleach

So if you have done all of the above and can’t figure out what your fiber is, then maybe you have a combination fiber. Maybe what you have is 50% wool and 50% acrylic. Then all of your tests will give mixed results. That can be kind of confusing. But don’t give up yet. Grab some bleach* and a clear jar with a lid. An old jelly jar works great.

Again with the safety warnings: Bleach can ruin your cloths if you splash it around and send you to the ER if you pour it in your mouth or eyes. Please try not to do that. ER trips ruin everyone’s day. Keep the furballs locked up in the bedroom.

Then fill up your jar with bleach, toss in a 6 inch sample of your mystery yarn, and seal up the jar. Come back to check on it obsessively every half-day or so. Animal fibers, like wool, will dissolve within 12 to 24 hours. Silk hangs on a bit longer but it should all be gone with 2 days. Cotton, bamboo and any other plant-based fibers can last for days, maybe even a week, in bleach but eventually they dissolve too. In the end, all you will have is acrylic or nylon. If you checked your bleach jar obsessively regularly, then you should have a general idea of what types of fiber and what percentages are in your mystery yarn.

* I highly recommend that you use household bleach for this and nothing else. I’ve read guides for conducting the dissolve-fiber test with lye and I hope you will pass on that. Lye is very corrosive and I think its too dangerous to have in the home. Handle lye with extreme care or, better yet, just don’t use it at all. 


That’s the end of all my tips and tricks. Hopefully you now have some idea what your mystery yarn is, how thick it is, how long, and what its made from. You may even have enough information to pin down the brand and manufacturer. But even if you don’t you should be able to decide if your mystery yarn will make a good baby blanket or a nice pair of gloves. You should have a better idea how to use it.


You got to play mad scientist with your stash! That’s always good for a fun time. And there wasn’t any math. Not really. Nu-huh.

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21 Comments on "How to Identify Mystery Yarn"

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Shirley Eagle

Why grams to figure the length of a quantity of yarn? Wouldn’t it work the same with any other unit of measure?


Grams measure smaller increments than ounces, & most postal scales use both, you can switch between the two. Bird owners tend to have them, because it’s more accurate when weighing a bird that’s only 50 grams (1.76 ounces)


Interesting, informative and fun! I love it when I learn something new.


I don’t do any of that, I use my nose!
I find wool has a distinct smell, I very rarely use silks Though had a phase of everything I made was silks, I’m over that now
Now my phase is cashmere, I buy from China it’s much cheaper than the £49.50 per 50g ball the Chinese cashmere I buy for around £1.50!
For a 50g ball.
I am a knitter not a spinner though I am thinking of having a go


There is only one issue with buying Chinese cashmere. T


Wow. My mind is totally boggled not only at the depths you went to in order to unravel -sorry, couldn’t resist 🙂 -these issues, but also how incredibly articulate you are in being able to actually be able to explain them to others…skills which do not often (unfortunately) go hand in hand. And with humor too.
Thank you!!!


Thanks for all the very useful info