Fabric Burn Test Quiz: Cotton, Silk, Polyester or Blend?

The burn test is a quick, rough way to check what a fabric is made of. Pull a few threads or cut a small snippet from a seam allowance or the end of a piece, hold it with tweezers over a metal tray or sink, and bring a flame to the edge. Watch three things: how it burns, how it smells and what it leaves behind.

Plant and regenerated fibres: cotton, linen, viscose

• Burn quickly with a yellow flame and keep glowing after the flame is removed.
• Smell like burning paper.
• Leave a soft, grey, feathery ash that crumbles easily. Viscose leaves very little ash.

Animal fibres: silk and wool

• Burn slowly and tend to go out when taken away from the flame.
• Smell like burning hair, because both are protein.
• Leave a dark ash that crushes to powder between your fingers.

Synthetic fibres: polyester, nylon, acrylic

• Melt and shrink away from the flame, often dripping.
• Polyester gives dark smoke and a sweetish chemical smell; acrylic flares and smells acrid.
• Leave a hard bead that does not crush. Polyester's bead is usually dark; nylon's is often lighter, greyish or tan.

Blends and limits

A blend shows mixed signs: for example, a poly-cotton snippet smells partly of paper but leaves some hard beads. The burn test cannot tell you the exact percentage, and finishes or coatings can confuse it. For pure silk, look for the Silk Mark label; for exact fibre content, a textile testing lab can test a sample.

Safety

• Test only a small piece, never a garment someone is wearing.
• Use tweezers, work over a metal tray or sink, and keep water nearby.
• Melting synthetics drip and stick: keep fingers clear.

Also try the fibres and yarn quiz.