How to Do the Burn TestBy Claire Ortega – 12 Comments
There are many ways to identify what kind of fiber or fibers is in yarn. Obviously, the label tells us the exact composition of the yarn (100% acrylic, 50% cotton 50% acrylic, etc.). But what do we do if the label is gone forever?
We can turn to texture. If the yarn is coarse, it should be acrylic; if it’s a little hairy, it should be wool; if it’s shiny and slippery it must be silk or rayon. Then again, modern technology has made acrylic yarn soft and shiny; there are even acrylic yarns that look like mohair yarn.
Enter: the Burn Test. When yarn is (quite literally) tested in fire, its fiber composition is seen more clearly.
Here’s what you’ll need:
- a long strand of the yarn(s) to be tested
- tweezers or tongs (to hold the yarn with)
- match or lighter
- a bowl of water
We’ll need a safe place to conduct this experiment. The ideal venue is a working sink, so if the flame goes out of hand, a water supply is readily available. It also wouldn’t hurt to have a fire extinguisher near you (just in case!). If there are any kids or toddlers running about the place, make sure they’re napping or busy before doing the burn test.
So let’s get started! Light the candle with your matches or lighter. With the tweezers or tongs, grasp your yarn and put it near the flame. From here we rely on our senses to distinguish one type of fiber from another.
Synthetic Yarns (Acrylic, Nylon)
- Smells like burnt plastic
- Flame does not extinguish for a long time, continuing along until blown on or submerged in water. Warning: don’t pinch the burned end; the melted synthetic material might cling to the skin.
- Yarn seems to be “eaten up” or melted by flame
- Does not leave ashes
- Burned ends turn black and harden
Plant-Based Yarns (Cotton, Linen, Rayon)
- Smells like burnt linen
- Flame continues to burn until blown on or submerged in water, much like candle niches
- Flame is easy to extinguish
- Fine ash, much like ashes from burnt paper, is left behind
Animal-Based Yarns (Wool, Silk, Alpaca, Angora)
- Smells like burnt hair
- Flame almost immediately dies down on its own
- Leaves charred, crisp ashes
It’s easy to tell the results of the burn test when the yarn composition is 100% of the same fiber. Today, though, yarn mixes are popular, combining the strengths of different fibers to produce a yarn intended for a specific project. What to do in this case?
The burn test should manifest the majority of the fiber content of the yarn. But if you want more specific results, and the yarn is stranded, you can untwist your yarn to reveal the different strands or plies of yarn, and test each individual strand.
I hope that was helpful! If you need anything, just leave a comment below.