Modern Silk Production: A Blend of Tradition and Demand

While silk production traces its roots back thousands of years, the industry that supplies it today is a modern, tightly organised operation concentrated in Asia. The insect at the centre of it, Bombyx mori, has been domesticated for so many generations that it can no longer fly or survive without human care. Everything downstream of that — the price of a silk pyjama set, the grade printed on a label, the weight in momme — follows from how this one caterpillar is farmed at scale.

The arithmetic behind a kilogram of silk

The scale is easy to underestimate. Producing a single kilogram of raw silk takes roughly 6,000 silkworms, and those silkworms will eat something in the region of 200 kilograms of mulberry leaves getting there. That is before anything is woven.

Each silkworm spins one continuous filament. The usable length reeled from a cocoon is most often quoted at somewhere between 600 and 900 metres, and the raw filament is far too fine to weave on its own — five to eight of them are reeled together under tension to make a single workable thread. A long pyjama set is therefore several hundred cocoons and a small field of mulberry.

That ratio is the whole reason silk costs what it does. It is not brand markup. It is agriculture with a very poor yield per hectare, and no amount of industrialisation has changed it.

Reeled silk, spun silk, and why the difference shows

Not all silk on the market comes off the reel. If a cocoon is damaged, or if the moth is allowed to hatch and break through the filament, the long strand is lost. What is left gets carded and spun like cotton into a short-staple yarn.

• Reeled (filament) silk keeps the full length of the strand. It is smoother, stronger, and it holds the liquid drape and quiet lustre people buy silk for.

• Spun silk is made from broken or waste cocoons. It is soft in a fuzzy way, noticeably less lustrous, and it pills sooner.

• Peace silk (ahimsa silk) lets the moth emerge before the cocoon is processed. Because the filament is broken it has to be spun, so it is coarser and, counter-intuitively, usually more expensive than conventional reeled silk.

Ours is conventionally reeled filament silk. We would rather say that plainly than let the word luxury do the work. You can see it across the whole silk sleepwear range.

Degumming: the step that makes silk feel like silk

Raw reeled silk does not feel like the fabric you know. It comes off the cocoon coated in sericin, a natural gum the silkworm uses to hold the filament together, and in that state it is stiff and dull.

Degumming — a controlled wash that dissolves the sericin — is what releases the softness and the shine. It also removes roughly a fifth to a quarter of the fibre's weight, which is another reason the finished cloth costs what it does. How carefully a mill degums is one of the clearest differences between good silk and cheap silk.

Reading the grade

Raw silk is graded on a scale that runs from C at the bottom up through B and A, with the A grades subdivided again. 6A is the top of that scale: the longest, most even filaments, the fewest slubs and joins, the most consistent thickness along the strand.

The grade tells you about the thread. The momme weight tells you about the cloth woven from it. They are two different measurements, and a seller quoting only one of them is telling you half the story. We use 100% Grade 6A mulberry silk, woven at 19 momme across the main sleepwear range — the Midnight Black long set is typical of it — and 22 momme for the heavier pieces. For the making process itself — from mulberry leaf to finished cloth — there is a longer piece on how mulberry silk is actually made.

Where silk is made now

China produces the large majority of the world's raw silk and has done for decades, with India a distant second and Uzbekistan, Thailand, Brazil and Vietnam making up most of the remainder. Production is seasonal, tied to the mulberry harvest, and concentrated in provinces where sericulture has been practised for centuries — the same regions that held the 3,000-year monopoly.

The industry was widely expected to collapse after the Second World War. Nylon arrived, then polyester, both a fraction of the price and available in unlimited quantity. Silk was supposed to become a museum fibre.

It did not happen. Synthetics took the volume market and left silk where it had always been — at the top — and demand has held remarkably steady ever since. Part of that is image. Most of it is that no synthetic has managed to reproduce what silk actually does: a protein fibre that breathes, moves moisture, sits at skin temperature rather than trapping heat, and creates almost no friction against skin or hair.

What this means when you are buying

Three questions cut through most silk marketing. Is it mulberry silk, or a blend? What grade is the raw silk? What is the momme weight? A seller who can answer all three is describing a real product. A seller who answers none of them is selling a word.