#the domestic silk moth cannot fly. we’ve bred it out of them.

[whimsicmimic]

one of these days i need to sit down with the butterfly + spider symbolism from tri98 and write a thing about spiders and silk moths — beings that are both capable of producing silk — and the inherent tragedy of the domestic silk moth (bombyx mori) + dependent plants

[rowanseas]

When you think of silk, you're most likely thinking of the kind of silk made by the bombyx mori variety of silkworm, which has been domesticated for over a thousand years. However, there's also a variety of "wild" silkmoths. They can be found in the wild, but they are also bred by humans for their silk. The most notable varieties, and ones you’ll probably see offered when looking for spinning fiber, are tussah, eri, muga and tensan. (You actually almost never see tensan silk for sale, but I’m including it because I love it.)

(Rest under a cut, because this got ridiculously long)

There's even several north american varieties of wild silkworm, most notably the polyphemus moth!

(photo of polyphemus cocoons from wormspit,com)

Each type of silk looks and feels slightly different, because it's made by different species of silkworm. The tussah and tensan varieties are a type of silkworm that eats primarily oak. The tussah variety is the Chinese oak moth (antheraea pernyi), and it has an ecru/beige/light brown cocoon. Whereas the tensan (antheraea yamamai) is the Japanese variety of oak silkmoth. It has a golden green colour cocoon, which unlike the tussah silk, is resistant to dyeing (but also resistant to staining).

Combed tussah silk top (image from Ashford)

Tensan cocoons and yarn (image from Azumino Tensan Silk Museum)

The cocoons of the tensan silkmoth can be more green or more gold, depending on how much direct light they receive while spinning their cocoons. More sunlight makes the cocoons a darker green.

Unlike the bombyx mori variety of silkworm, the tussah and tensan varieties only have one brood per year, unless you give the eggs artifical cold treatment. (ie stick the eggs in the fridge for a few weeks to pretend it's winter.)

The muga silkworm is another of the wild silkworms, from the Assam region of India. It's latin name is antheraea assamensis, and it's also known as the Assam silk moth. It's silk is a glossy gold/bronze/brass colour.

Muga silk top (image from DivinityFibers on etsy)

Eri silk is made from the samia ricini species of silkworm, and it primarily eats castor beans, tapioca leaves or cassava. It's also known as "peace silk" since the cocoons of this variety cannot be reeled, so the moths hatch out and do not have to die to produce their silk. Eri silk can range anywhere from a light gold/beige colour to an orangeish red.

“Red” Eri silk (image from treenway silks)

The bombyx mori or the mulberry silkworm is the most commonly known silkworm. It was domesticated from the bombyx mandarina wild silkworm. It's been domesticated so long that the moths can no longer fly at all, and the caterpillars are nearly helpless.

So now that we've had a rundown on different species of silk, let's get into the different preparations of silk you can find (and how they're processed!)

There's several different stages and preparations of silk you can find to use to make silk yarn. Silk caps or hankies are one of the most "finished" product you can find as a spinner to work from, made from taking the cocoon and stretching it over either a hoop shaped frame or a square one. The difference in shape is how you get the "cap" or "hankie" shape. Most caps and hankies come in a stack, since it's easier to stretch a few cocoons over the frame to stack up the layers.

A stack of silk caps (image from treenway silks)

Silk top (another of the more processed silk preparations) is often made from the extra floss that silkworms make in preparation for spinning their cocoon and holding it in place. (The images of the tussah, muga and eri silk are all silk top for reference.)

You can also find cocoons for sale, and process them yourself. You need to degum the cocoons, as the sericin, which is the glue that holds them together, keeps the silk fibres tightly glued.

Cocoons are made from one continuous strand of silk, so when the cut cocoons are processed, sometimes you get bits of silk that are a few centimetres long and some that are several metres long. When carding cocoons, sometimes you need to go in with a pair of scissors and cut the staple length to a more reasonable size. (Just pull the carders apart to a reasonable distance and snip in between! Reasonable is up to the spinner's discretion.)

A cut cocoon with pupa peeking out, with whole cocoons below it. (image from wikipedia article on Ahimsa silk)

There's also getting silk from the whole cocoons, where the pupa is still inside. This is an entirely different process from spinning the silk, and is called "reeling." Most silk fabrics are made from reeled silk.

Reeling involves taking the single silk thread from the cocoon as one single length. You need to take the fibers from several cocoons at once, as each individual fiber is very fine, and if left as a single fiber, extremely prone to breaking.

There's several methods to reeling silk, but the one I've researched best is the Japanese method, so that's the one I'll be describing. A good chunk of my knowledge is from http://www.wormspit.com/silkreeling.htm and http://www.wormspit.com/newreeling.htm

To reel silk, you take the whole cocoons (you'll want a few dozen of them) which have been stifled (bake them so the moth doesn't hatch) and put them in a pot of near boiling water. This is to help loosen the sericin. Then you take a brush and brush along the cocoons to find the loose end of the silk fiber. You'll want to get around 8-20 cocoons. Transfer them to another water bath which is slightly cooler, but still warm.

The next step is feeding the reeled silk filament through a croissure, which is a pair of pulleys, with the silk looping back on itself. This squeezes some of the water out of the silk and also squishes the individual fibres together better, where they are glued together by the leftover sericin still in the fiber.

(image from wormspit)

The silk is then reeled onto a reel, where you have to be careful to make sure that the layers of silk you're winding onto the reel don't lay directly on top of the last layer. (You'll want to make sort of X shapes instead of /// shapes.) This keeps the silk from glueing itself to the previous layer.

After reeling, you need to re-reel the silk, to help it dry and keep it from sticking to itself. You can then re-re-reel it onto a cardboard tube, or store it in hank form.

(image from wormspit)

To turn the reeled silk into yarn, you then need to "throw" it, which is adding twist to the reeled silk. This is the stage where your spindle/spinning wheel comes into play!

As silk is so fine, most yarns are made from several strands of the reeled silk that was made in the last step.

Once you have made your thrown + reeled single, you can then ply it, or work with it on it's own. If weaving, you might not want to remove the left over sericin, as the sericin gives the fabric a bit more body. However if you intend to knit/crochet/sew with the resulting yarn/thread, you'll want to degum it.

The mulberry silkworm is the most common silk to be reeled, but you can also reel tensan and muga silk cocoons. However, finding cocoons that are whole for sale is nigh impossible, so if you want to try reeling, you'll have to raise the silkworms yourself!