Fabric Burn Testing

How to identify the fibres in mystery fabric!

Anyone who buys second-hand fabric knows that you have to make peace with not knowing the exact composition of your fabric. Whether you scour eBay for the perfect vintage sheets, or love rummaging for treasures in charity shops, or even buy deadstock – a fabric mystery is a fact of life.

However, you don’t have to be completely clueless! A carefully controlled burn test could give some valuable insight into what fibres are in your fabric, if you know what you are looking for…

What to look for when burn testing:

How does it burn? Does it catch quickly or slowly? Is it curling? Does it burn up or fizzle out easily?

How does it smell? Does it smell like paper, hair or chemicals?

What do the ashes look like? Black? Grey? Shiny?

What do the ashes feel like? Hard, crunchy or powdery?

How to do a burn test safely:

Before you start, cut some small samples of your mystery fabrics. Grab a pair of long tweezers to hold the fabric away from your fingers and light a candle. It’s best to avoid matches as they have that match-smell which means you will have a harder time identifying the smell of your mystery fabrics as they burn.

Hold the fabric above the flame and once it catches fire, place it on something flame-proof such as plate or baking tray. This way you can observe it as it burns without risking your fingers. I would also advise having a glass of water to hand, just in case!

Fabric burning test

Let’s dive into some common fabrics!

Cotton will burn quickly and brightly. It will likely smell strongly of paper. The ashes will be grey and powdery and disintegrate easily. There will be a long afterglow after the fire goes out.

Linen will burn a lot like cotton, quickly and brightly. This smelled like paper but not as strongly as the cotton. The ashes are grey and powdery and again there was a long afterglow.

Cotton burn testing
Linen burning test

This burns up quicker than the cotton and linen and almost disappeared entirely. It smelled delicately of paper and mostly burned up, leaving behind grey ashes and an afterglow. Cellulose based fabrics will all behave like this so burn testing won’t help you identify the difference between modal, bamboo, viscose and Tencel etc.

100% wool will be reluctant to burn but when it does finally catch fire, it will smell of burning hair. The ashes left behind feel hard like charcoal but will crumble between fingers.

Viscose burn testing
Wool buring testing

Synthetics like polyester will immediately start melting rather than burning. The fabric will curl, melt and cool to a hard bead. It smells like chemicals.

Silk will likely recoil and curl away from the flame but instead of melting it will burn. It will also smell of hair although not as strongly as wool. The ashes left behind feel hard but will crumble between fingers.

Polyester burning test
Silk burn testing

Ultimately, some of these fabrics burn in very similar ways (linen and cotton for example) so if you don’t feel confident making a guess, you can usually figure out which category it falls into:

Plant-based fibres will ignite quickly and burn easily, giving off a smell of burnt paper, and leave powdery, ashy remains. These are likely to be cotton, linen, viscose or bamboo.

Animal-based fibres don’t ignite very easily. As they burn, they smell more like burning hair and leave hard crunchy ash behind. These are likely to have wool or silk content.

Synthetic fibres melt rather than burn when held over a flame. As they burn, they smell chemically and leave behind hard plasticky beads. If a fabric behaves in this way it is likely to be polyester, nylon, acetate or another synthetic.

As you get more familiar with fabrics and burn testing you might get better at interpreting fabric blends, for example a thick fabric that smells like hair but leaves plasticky beads is likely to be a wool & synthetic blend.

Please be mindful, these experiments can be done outside or in the sink for extra caution if your mobility is limited or reaction times are slow. Never leave a flame unattended and do these tests away from animals and children. Most importantly, you can find out lots of information from burn testing, but remember – if you bought the fabric because you liked it, then it doesn’t really matter what it’s made of – sew it up and enjoy it!

If you’d like to find more sewing tips like this Fabric Burn Testing
to grow your sewing skills – click here

Vicky Hall