Silk is produced from jelly substances secreted by the bombyx mori silkworms to form the cocoon where larvae transforms into an adult moth, which is native to all continents. The secretion hardens upon exposure to air, forming what is known as a filament. The hardened filament is tightly held together by sericin, a silk gum. The silkworm spins layers of the single filament and a cocoon is formed. Each cocoon is composed of a single thread, measuring approximately 914 meters (3,000 feet).
A series of hot and cold water immersions soften the silk gum and loosen the filament, leaving it ready to be reeled and spun into a silk thread. In instances where the silk is used as a filling, softened filaments are manually stretched and layered to form the comforter batting.
In general, spun silk is soft and lightweight. When touched or wrapped around the body, you’ll immediately notice the distinct smoothness of silk.
Raw silk is generally characterized as being soft and lightweight. It has a very fibrous appearance, similar to cotton. Silk fibers tend to cling to one another, forming the comforter batting. Pure silk should be pearly white with a slight sheen.
The "burn" test is the easiest (and best) way to determine if a fiber is truly silk. Place a flame under a piece of either raw or spun silk. Silk fibers burn on contact but extinguish upon removal of the flame. True silk leaves a powdery ash residue.
Silk has several different grades. Short floss silk may merely be remnants or broken cocoon silk. However, long floss silk is extracted from whole cocoons with one continuous filament-some as long as 3,000 feet! Long floss silk tend to adhere to one another, making it less likely to pull apart. SV Silk comforters are filled only with the finest long floss mulberry silk.
Types of Silk
A silkworm’s diet determines the type of silk it will produce. Bombyx mori silkworms love to eat Mulberry leaves. A diet rich in Mulberry produces the finest, whitest cultivated silk fiber available known as Mulberry Silk. When the bombyx mori are not dining on Mulberry, their silk is referred to as Wild Silk, which is usually a rougher, lower-quality product than Mulberry silk.
Silk doesn’t felt, and should be washed in the same way as wool fibers unless the dyes used on the yarns are not color-fast. In that case you’ll want to hand wash and rinse in cool water and mild soap, finishing with a splash of vinegar in the final rinse. Hang or lie flat to dry, depending on the weight of the fabric. Silk will stretch in a looped fabric, so make large swatches and hang for a day or so before measuring.