Before the cocoons are boiled, they are dried in sunlight or dryers for 3 days in order to kill the silkworms in the ocoons.
If the pupa become adult moths and leave the cocoons,
there will be holes in the cocoons which cannot be used for producing silk fibers.
Silk reeling refers to the process of extracting silk threads from the cocoons according to the required amount.
The cocoons are boiled at the temperature of 60ͦ C to soften
the sericins in the cocoons for an easy reeling. A typical single thread is made from 50 cocoons / thread. In silk reeling, cocoons are boiled in hot water for 5-10 minutes before the threads are reeled by using wooden tongs to stir cocoons
in the containers.
Several tiny threads sticking on the tongs are reeled into a single silk thread. One cocoon can be used to produce threads with 500-800 meter long.
Typical cocoons are in two colors: yellow and white,
depending on their species.
The white cocoons are from Chinese specie
whereas the yellow ones are from Thai specie.
The threads reeled from the cocoons are called “raw silk”, with rough fibers and difficult to be dyed.
The raw silk threads have to be cleaned and bleached to make them gentle and shiny. After that the silk threads are dyed.