How is Mulberry Silk Made?

December 27, 2018

Mulberry silk is an ancient material that’s been cultivated in Asia for thousands of years. Have you ever thought about the life of it before it becomes your bedding, specifically how the filling is made? Because mulberry silk has such a luxurious feel and is packed with benefits for the best quality sleep, you may be interested in learning more about the (fascinating) process of production.

Strict Diets

Silkworms are caterpillars of the Bombyx mori moth, which means "silkworm of the black mulberry tree". While different types of silk can be produced based on what the caterpillar eats, the most important thing to know about mulberry silk is that the caterpillars eat a strict diet of mulberry leaves ONLY. Other lower quality silks are made from caterpillars who eat osage orange and lettuce versus mulberry leaves. Lower quality silk also requires more processing than mulberry silk to get rid of the dingy yellow color and unpleasant odor, often associated with lower quality silk.

Life Cycle of a Silkworm

Like most insects, silkworms go through four developmental stages: egg, larva, pupa, and adult, in which the adult stage is the silkworm moth. The larva is the silkworm caterpillar, and they have to shed their skin four times while growing due to the huge amount of growth that they undergo.  The times that they shed their skin, which is kind of like a stage within a stage, are referred to as instars.  Silkworms do approximately 85% of their eating during their fifth instar, and they reach about three inches in length.  By this time, the larva grown 10,000 times its original size since birth, and its glands now make up 25% of its body weight! This means that it’s ready to spin its silk cocoon.

An Art Form and a Science

As for the actual production, this is things get a bit more technical. We found this awesome explanation on the website, Today I Found Out:

 “During its 3 to 8-day pupating period, the silkworm secretes fibroin, a sticky liquid protein, from its two sericteries (special salivary glands). Pushed through a spinneret (opening on the mouth), the twin pair of continuous threads harden when they come into contact with the air. Next, the silkworm secretes sericin, a bonding agent, from two other glands to hold the two filaments together. While constructing its cocoon, the silkworm will twist in a figure-8 motion about 300,000 times and produce around 1 kilometer of the filament. Since hatching from the cocoon destroys the thread, to harvest the silk, the cocoon is placed in either boiling water or blasted with steam or hot air. The heat softens the binding agent (sericin), so that the filaments may be unwound. Sometimes, the softened sericin is left on the fibers, and this product is called raw silk. From there, the strands are twisted together until a fiber of sufficient strength for knitting or weaving is produced. “

What else do you want to learn about mulberry silk? If you’re interested in learning about its properties and features, check out our blog. If you’re ready to experience its luxury for yourself, shop now.


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