Fire and Yarn

I have a rather large amount of yarn in my stash. I could use the "I live on an island" excuse, but the truth is my stash represents 20-plus years of yarn acquisitions and it was just over 4 years ago that I started living on an island. I guess I just like yarn.

My stash falls into four categories:
1 - Yarn I bought with an intended purpose, but haven't yet knit up
2 - Yarn I bought with no specific intent, but was sure I could put to good use
3 - Yarn left over from a project I have finished
4 - Yarn given to me by friends and acquaintances working on downsizing their own stashes (I'm a sucker for FREE yarn!)

The last two categories in particular include some skeins that look like this.

No label. No idea of it's fiber content. Or gauge. Or recommended needle size. For that matter, I have no idea how this skein ended up in my stash. I don't recall knitting anything out of this yarn - although my memory on that front is not all inclusive.

So, what to do.
Well, touching the yarn gave me clues -- light-worsted to worsted weight, so needle size around 6-8. I could even make some guesses about fiber content. At a minimum, I could be fairly sure it wasn't cotton or linen or another plant-based fiber. My guess was that it's wool or acrylic or a blend. To test my guess, I decided to burn a small piece.

Way back when I lived in New York, I took a few classes at the Fashion Institute of Technology and one of my absolute favorites was Fabric Science. We learned about the characteristics of all kinds of fibers including what happens when you burn them - which turns out to be one of the ways to identify the fiber content of fabrics.

I once saw this in action at a fabric store in Manhattan. A customer asked the owner if a piece of fabric was 100% cotton. The owner cut off a small bit of the fabric, lit a match and burned the edge. (Cotton is a cellulose fiber. When it burns, it smells like leaves or wood burning. It leaves a soft, fine, gray ash - like leaves or wood.) But I digress ...

So, back to my unknown yarn. I brought a candle into the kitchen (very close to the range hood and the sink).

Cut off a piece of the yarn

Lit the candle and held the yarn up to the flame.

I quickly realized that I really wanted to hold the piece of yarn with something other than my fingers!

Much better! I pulled the piece away from the flame and the yarn continued to burn until I extinguished it. (Big clue.)

For comparison, I cut off a small piece of yarn that I knew to be 100% wool.

And held it up to the candle flame

It burned, but as soon as I pulled the piece away from the candle, the fire went out.

This was right in line with what I remembered from my old Fabric Science class. Wool is a "self-extinguishing" fiber. It will burn when in contact with fire, but will not continue to burn on it's own.

The two pieces smelled different when burning. The wool had a smell a bit like burning hair. (As in when you burn your own hair with a blow dryer or curling iron.) The unknown sample had a sharp, almost fishy smell.

Finally, I examined the burnt edge of my unknown sample

Kind of crispy, as much a melted edge as an ash edge.

As compared to the burnt edge of the wool

Definitely an ash edge.

So, what do I know about my unknown sample? I can rule out 100% wool as the fiber content. It has the burn characteristics of a petroleum-based synthetic fiber (acrylic, polyester, nylon). Since it's a skein of yarn, rather than a piece of fabric, my guess is that it's 100% acrylic or perhaps mostly acrylic with a bit of wool. (In my experience, acrylic is the most common petroleum-based synthetic fiber used in knitting yarns.)

Why does this matter? I used this yarn in combination with other yarn. I knew the fiber content of those and wanted to be sure they would work together. I was quite pleased with the end result ... and that will be the subject of my next post.