Fabric Burning

Sometimes I'll get a scrap of fabric without knowing it's content.  It's not always very easy to tell the difference between a real silk satin and a polyester satin by touch alone, so I'll test burn fabric to determine the content, and surprisingly, it's not nearly as hard as it seems.  I snip a small piece of the fabric to be determined and burn it over a metal plate.  Depending on how easily it ignites, what the flame looks like, and how the charred ash looks and feels, you can determine the fiber.  It helps to first test a piece of fabric which has a known fiber content so that you'll have an idea of what you're looking for.  I also keep an inventory of fabrics I've already tested so that I can always have a test scrap on hand if I'm unsure of a piece's content.

Here's a basic guide, but the internet is full of information, if you want more.

-Polyester or acrylic fabrics will melt (much like plastic) and harden into a black, melted mess.

-Wool smells like burning hair and the burnt fibers become crispy. It's also a bit harder to light than cotton.

-Cotton smells much like burning paper, lights and burns easily, and the fibers will become a fine powder when rubbed between fingers.

-Silk smells much like wool, but the burnt fibers are slightly less crispy and they don't ball up as easily as wool.  The fabric seems to char and then burn, so it leaves a larger charred section on the scrap. I don't know if this is because of the way it's woven, or if it has to do with the content, but that's been my experience.