What to Do with All Those Empty Cocoons

We see silk scarves and silk blouses in the department stores. Fabric outlets sell bolts of different silks. All silk comes from cocoons and we're quite familiar with those. But how does the silk get from oftentimes hard cocoons to the soft and luxurious fabrics that we favour? The cocoons are degummed, the silk is then spun, and finally woven into fabric. Scarf from 100 % silk by Kay Cheever.

Most silk clothing and fabrics are made of fibres from Bombyx mori cocoons. Bombyx mori, the cultivated silkworm, is no longer found in the wild. Larvae will only eat leaves of the mulberry tree and they produce a beautiful white and lustrous silk.

But wild silkworms produce beautiful silk as well. Some are even available commercially, for example, the Tussah silk from Antheraea mylitta or Antheraea pernyi. These emerged Antheraea pernyi cocoons have been slit open to remove and discard larval skins.

You can buy silk in many forms: cocoons, roving, noil or mawata (sometimes called hankies) to name a few (see glossary at end of article).

So how do you get a usable fibre from the cocoon? I'll explain one approach.

To begin, I like to sort the cocoons according to type, i.e., all like cocoons together. I remove any old leaves and twigs and frass and then slit the cocoons and empty them of their contents. You don't have to do this, but I think it's easier to remove the "trash" first before it gets wet and slimy. For some forms of silk, like mawata or reeling, you shouldn't slit the cocoon, but, with this method, it is advisable.

Next the cocoons need to be degummed in a process also called "stripping","boiling off" or "schapping". The process may remove all the gum/seracin, or at least a large portion of it. Simmering softens the cocoons and leaves them more manageable. Use a slightly alkaline solution and "cook" at low heat for about an hour. Use enough water so the cocoons aren't crowded. Dissolve 4 oz. of washing soda and 4 oz of real soap (I grate a bar of ivory soap) to one pound of cocoons. When the soap is in the pot of water, I bring the contents to a boil and then test the solution with litmus paper. The proper pH is about 9.5.

When I have the proper pH, I add the cocoons and simmer for 1/2 - 1 hour. Cocoons will float, so you might want to use a lid or a plate to keep them submerged.

Some cocoons take longer than others to degum. Check them. When they no longer hold that cocoon shape and are softened, you should rinse them several times. If you did not empty the cocoons beforehand, you can ease the pupae and dicarded skins out through the softened silk during the last rinse. Squeeze out excess water and let cocoons dry, away from direct sunlight which can danmage silk.

Carol sent me some sample cocoons in the dried, degummed condition. A cecropia, in particular, was quite interesting and I tried "fluffing it out" as described and depicted below.

After the cocoons are dry, you can pull one out and fluff it out. Grab the cocoon in the center and with two hands give short, jerky pulls. Move the cocoon around and fluff out until it looks like a fluffy ball.

Now you can place the leader from the spinning wheel on top of the fluffed out cocoon and start treadling while keeping the leader and cocoon together. Once it catches, hold the join with one hand and with the other hand, pull the cocoon away from the join. Don't pull too far that it separates completely; you just want enough fiber to twist into your yarn.

You can also card or comb the cocoons. Carding is like brushing your hair. You can cut the cocoons into fourths and card. Both spinning from the cocoon and carding will give you textured yarn. That's because both the long fibres and short noil are used. When you comb the cocoon, you remove all the short noil and will get a smoother yarn. It all depends on the desired "look" and use.

Cocoons can make a strong lightweight yarn suitable for knitting, weaving, crocheting and stitching. And silk dyes beautifully. Clockwise starting in top left: skein, B. mori dyed with black walnut skein, B. mori dyed with mulberry leaves cocoons of B. mori skein of undyed spun cocoons skein, B. mori dyed with goldenrod skein, natural Tussah chemically dyed cocoons

Glossary:

roving--a continuous length of carded or combed fiber
noil--the short fiber
mawata--several layers of cocoons stretched into a square.

Thanks for sharing, Carol. I have just sent you a box of "empties". Below are a crocheted doily by Frances Ardzinski, Carol's mom, and a purse knitted by Mari Trott. In both cases the silk was spun by Carol Neeves.