Silk and silk production have a rich history dating back several thousand years. The formal name given to silk production is sericulture. It is a process invented and perfected by the Chinese, and a secret they were able to keep from the rest of the world for several thousand years by different means, including putting anyone to death who tried to smuggle the secrets of sericulture or the silkworms out of China.
Today, sericulture has been mastered by many countries although it is still the Chinese who produce more silk than any other country in the world, about half of all silk. They are true masters at the process of raising silkworms, harvesting their cocoons, retrieving the silk filament from each of the cocoons, spinning it into silk thread, weaving it into silk cloth, dying it, and lavishly embroidering it.
How is silk made?
It is an exacting and demanding process. The most prized silk is obtained from a special type of silkworm, one that comes from the Bombyx mori moth. It is a moth that cannot fly and cannot see. Its only purpose in life is to lay the eggs that will produce the next generation of silkworms.
The Bombyx mori moth lays about 500 eggs over a period of four to six days and then dies, having completed the job it was meant to do. The eggs are very tiny, like little pinpoints. All five hundred eggs together only weigh about 5 grams or a little under 2 ounces. It takes approximately 30,000 silkworms to produce twelve pounds of raw silk. Those 30,000 silkworms will eat about 2,000 pounds of chopped mulberry leaves from birth to the time they weave their cocoons which is about a month after they are born.
Why is the silk from the silkworms produced by the Bombyx mori moth that is fed a diet of only chopped mulberry leaves so prized? Unlike the silk that comes from wild moths who eat whatever food is available to them, the silk thread filament the Bombyx mori moth produces is a much higher quality. It is finer, smoother and rounder than the silk from the wild moths. Also, silk produced from wild moths is not uniform in length, color or shape which produces silk that is less smooth and may have short or broken threads in it.
It may not sound like it is all that difficult to hatch the eggs of the Bombyx mori moth, grow the silkworms, and harvest the cocoons but it is.
First of all the eggs need to be kept at 65 degrees Fahrenheit and slowly increased to 77 degrees so the eggs hatch properly.
The baby silkworms need to be fed chopped mulberry leaves every half hour around the clock while care is taken to maintain an environment that is stable, with a fixed temperature as well as making sure they are not subjected to loud noises, strong smells such as those from fish, or even the smell of human sweat.
Once the silkworms happily eat their way to 10,000 times their weight at hatching time, which only takes them about a month, they have enough energy to spin their cocoon. That takes them three to four days. The cocoon looks like a little white fluffy ball. The cocoons are kept in a warm place for about 8 days. Then the cocoons are steamed or heated to a higher temperature to kill the silkworms inside them because they have now completed the job they were meant to do.
Great care is taken to ensure the silkworm does not hatch into a moth because then the long silk thread filament that the silkworm has made its cocoon out of will get broken.
After the cocoons are heated or steamed, they are placed in water to loosen the silk thread filament. Then the filaments from between four and eight cocoons are twisted together to make one silk thread that can be as long as 1,600 yards which I think is an amazing fact. Its hard to believe that the cocoon from one silkworm can be one continuous filament that long, but it can be.
Finally, there is one strand of silk thread. Is it any wonder that silk is expensive? The process of making it is painstaking yet amazing.
The next time you run your fingers over a luxurious piece of silk or buy a set of silk bed sheets think about the amazing process and workmanship that turned the cocoons of the silkworm into such a wonderful piece of fabric.