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Loom FAQs: What Is A Burn Test? Why Burn Yarn At All?







We have all been there.  Go to a thrift store or yard sale and find a stash of yarn being sold for dirt cheap.  Cannot pass it up because IT IS DIRT CHEAP.  And better yet, it’s clean and usable yarn.  Doesn’t have an odor or feel weird.  Appears to be clean and ready to use.  Might still wash it after the project is made though…

But one thing is missing.  The label.  On several of the skeins.  And since there is such a variety of different kinds of yarn in that stash, there is no way of being certain that is the same kind of yarn.  It feels or looks different from anything else you have.

Or you are not the lucky sort to find these kind of deals and just end up buy a bag of mill ends that is still a mystery even though you bought it at a retail store.

What is it?  What kind of fiber is this mystery yarn?  Will I be able to block it?  Can I use it as a gift for someone who is allergic to wool?  How can I find out what the fiber content of this wonderfully cheap mystery yarn actually is??

Well you are in luck.  There are ways to find out the fiber content of yarn.  And it’s fun too.  BY BURNING IT.  Why would I burn it?  Then I wouldn’t have it.  Well you don’t burn the entire thing.  Just a small piece.

Please note!!  Please take every precaution about using open flames in your home so that your entire stash doesn’t burn with the rest of the house.  I mean, we all love firefighters.  And calendars of shirtless firefighters.  Just don’t go and try to meet all from the firehouse all at once by accident…  And please do not use me as an excuse to your significant other as a reason there was a fire in your home or why you have burned your hand.  But Renita said you can burn the yarn to see what it’s made of!!  It’s her fault.  Just use some common sense before setting anything at all on fire.  Even a candle.

What is a burn test?

A burn test is a simple way to tell if the yarn is 1 of 3 fiber types, synthetic (acrylic, nylon, etc.), plant base (cotton, linen, bamboo, rayon, etc.), or animal (wool, silk, alpaca, angora, etc.)

Why can I not tell between different types of animal or plant?

Since all of each fiber types will burn the same, there isn’t a way to tell between the different animals or plants or man-made fibers.  While some people can tell between silk and wool, the way those burn will remain the same.

How do I do a burn test?

First you will need to take all safety precautions like mentioned earlier.  A bowl or sink full of water is a great way to start.  If you are more accident prone, go ahead and have that fire extinguisher out and ready that we are all to have already in our kitchens.  Never hurts to have that handy just in case.

Then you will need to cut off a piece of the yarn.  About 6″ to 12″ will suffice.  Want it long enough to see how it burns and how easy it is to put out.  But not too long or too short that you can lose control easily.

Then light one end of the yarn on fire using a match, lighter, or other open flame while holding it over the prepared water.  You may need to use the water to put the flame out if blowing on it like a candle doesn’t work.  Or the flame gets out of the control and you really need to just drop it.  That water is going to come in handy.  Just take my word for it…

Do NOT pinch the flame out with your fingers!!  If the yarn is synthetic, you are basically burning plastic and run the risk of the melted plastic adhering to your fingers.  Not something you want to happen.

What does it tell me when I do a burn test?

Below are the results of burning each fiber type.

Each type will have different results in how it smells, how it burns and if it extinguishes itself or must be extinguished by you, and the way it burns and whether it produces ash or not.

And yes.  I have conducted the burn test myself and have smelled each one.

Synthetic (acrylic, nylon, etc.)

– smells like burnt plastic

– the flame will burn fast and will continue to burn until it is extinguished by blowing it out or submerging it in water

– the burnt end will not turn to ash and will harden like melted plastic while turning black

Plant (cotton, linen, bamboo, rayon, etc.)

– smells like burnt linen which it should especially if it’s linen…, (I saw it described that way before and just had to include that sweet little nugget of information…) In other words, it has a “clean” smell when burnt

– the flame will continue to burn until it is extinguished and is easy to extinguish like a candle wick by blowing t out

– the burnt end turns to fine ash like burnt paper ash

Animal (wool, silk, alpaca, angora, etc.)

– smells like burnt hair

– flame will almost immediately die out on it’s own without the need to extinguish, if it doesn’t then it may be a blend

– leaves crisp, crunchy ash that is larger, may stick together until broken apart, and not fine like plant fiber

What if the yarn is a blend?

Usually the burn test will determine the highest of the fiber content used.  It may or may not burn differently depending on the content of each fiber when it’s a blend.  There is not a sure fire way to know what the percentage of each fiber is.  Did you see what I did there…  

If the yarn is plied with multiple strands, you may try separating the strands and conducting the burn test on each strand.  Sometimes with blends, the strands that are plied together are actually different fibers.  Most times though all the different fibers are carded together before they are spun.

One way to tell if it’s a blend is by looking closely at the colors in the strand.  If the strand of yarn has slightly different shades of the same color, it is most likely a blend of more than one fiber.  Different fibers take color dye differently causing a variation of color shade in the same strand of yarn.

Can I try it on something I know first?

A great way to know what it looks like and smells like when burnt is to do a burn test on yarn you already know the fiber content.  Trying to describe how it smells and looks is harder than it sounds, and everyone smells things differently.


While the burn test will not give the most definitive answers, it will narrow down the fiber type tremendously making it easier to know how to use, block, and clean the finished projects made with the mystery yarn.

For more answers regarding the yarn weight of the mystery yarn, please check out my previous article Loom FAQs:  What Is WPI And Yarn Weights?

Now you know basically what the yarn is and are ready to cast on your loom.  Well get going!  Happy loom knitting!!

One comment

  1. opal geminiani

    i was wondering after i e wrap and i have too do a purl stich next do i cast on again too make 2 on the peg ?

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