Year of Natural Fibers Series – June: Silk

Presenting: Awbury’s 2019 article series on natural fibersClick here to learn more about this year’s theme.

Articles written by La Salle graduate and Awbury intern Dan Sardaro.

June 2019 –  SILK: 

a silkworm cacoon, the source of silk threads

Silk is our natural fiber for the month of June, and it’s safe to say that this fiber has just as much history as the others that we’ve already learned about. Originating in Asia millennia ago and spreading across the globe, silk has a undergone a long, colorful lineage that begins in legend and spans civilizations. In this post, I’ll explain just how rich that lineage is.

Silk traces its roots back to the early days of China when Huangdi, the mythical ruler, reigned over China around 2700 B.C. Huangdi is credited as a great leader who brought military and technological success to his empire, but it was his wife, Lady Hsi-Ling-Shih, who was the brains behind silkworm rearing and the invention of the loom. It was her discovery that set in motion one of the most prized, luxurious industries in the world. Eventually, the silk industry would span the entire length of Asia and Europe thanks to the Silk Road, and become a staple to a world economy.

Now that I’ve mentioned things like worms and looms, I probably should explain how silk is created. Silk, like all of our fibers this year, is naturally occurring, but the process of systematically producing the fiber is called sericulture. That process started by the ancient Chinese begins with the silkworm (Bombyx mori) which is the larva or caterpillar of the moth that produces the actual fibrous material. This particular moth is completely domesticated, meaning that it cannot survive in the wild as its only purpose is to make silk. One moth can lay approximately 500 eggs in the span of its short life, creating thousands of offspring that have the potential to create close to a hundred pounds of silk.

silkworms eating through leaves

However, one of the most fascinating parts of the sericulture process is how the silk is made and harvested. From its time as a young larvae, the silkworm eats an exorbitant amount of mulberry leaves. It grows in size until it’s time to wrap itself in a cocoon made from – you probably guessed it – silk. The fibrous strands emerge from the head of what is now a caterpillar and surround the insect in one continuous thread of silk. Once the cocoon is complete, heat or steam is added to kill the larvae so that a full-grown moth does not break through the meticulously spun cylinder. Now left with just the silken cocoon, softening the hardened cylinder ensures that it can be easily unwrapped.

Yes, I said unwrapped. Turns out that the easiest way to obtain an unbroken strand of silk is to find where the worm left off. So once the end is located, the cylinder is uncoiled. What’s left is a two to three-thousand-foot-long strand of silk! Several strands are usually unwound simultaneously and spun together to create a stronger fiber, and after boiling the fibers to rid them of any impurities, they can then be used to make the smooth fabric we all are familiar with.

Today, Japan and China are the leading silk producers. Together they make more than 50% of the world’s silk. But even with the rise of other man-made products that can replace the natural fiber, silk production has almost doubled over the last 30 years. It is a testament to the fiber’s elegance and vibrant history, a history that I think will continue for many years to come.