Most hand-woven Thai silk is produced by Isaan village women, some of whom oversee every aspect of sericulture, from the breeding of the silkworm to the dyeing of the fabric. Isaan’s pre-eminence is partly due to its soils, which are particularly suitable for the growth of mulberry trees, the leaves of which are the silkworms’ favoured diet. The cycle of production begins with the female silk-moth, which lives just a few days but lays around 300–500 microscopic eggs in that time. The eggs take about nine days to hatch into tiny silkworms, which are then kept in covered rattan trays and fed on mulberry leaves three or four times a day. The silkworms are such enthusiastic eaters that after three or four weeks they will have grown to about 6cm in length (around ten thousand times their original size), ready for the cocoon-building pupal stage.
The silkworm constructs its cocoon from a single white or yellow fibre that it secretes from its mouth at a rate of 12cm a minute, sealing the filaments with a gummy substance called sericin. The metamorphosis of the pupa into a moth can take anything from two to seven days, but the sericulturist must anticipate the moment when the new moth is about to break out in order to prevent the destruction of the precious fibre, which at this stage is often 900m long. At the crucial point the cocoon is dropped into boiling water, killing the moth (which is often eaten as a snack) and softening the sericin, so that the unbroken filament can be unravelled. The fibres from several cocoons are “reeled” into a single thread, and two or three threads are subsequently twisted or “thrown” into the yarn known as raw silk (broken threads from damaged cocoons are worked into a second-rate yarn called “spun silk”). In most cases, the next stage is the “de-gumming process”, in which the raw silk is soaked to dissolve away the sericin, leaving it soft and semi-transparent. Extremely absorbent and finely textured, reeled silk is the perfect material for dyeing; most silk producers now use chemical dyes, though traditional vegetable dyes are making a bit of a comeback.
These days, it’s not worth the bother for women who live near town to raise their own silkworms and spin their own thread as they can easily buy Japanese ready-to-weave silk in the market. Japanese silk is smoother than Thai silk but lasts only about seven years when woven into a sarong; hand-raised, raw Thai silk is rougher but lasts around forty years, and so is still favoured by women living in remote villages.
Once dyed (or bought), the silk is ready for weaving. This is generally done during slack agricultural periods, for example just after the rice is planted and again just after it’s harvested. Looms are usually set up in the space under the house, in the sheltered area between the piles, and most are designed to produce a sarong of around 1m by 2m. Isaan weavers have many different weaving techniques and can create countless patterns, ranging from the simplest single-coloured plain weave for work shirts to exquisitely complex wedding sarongs that may take up to six weeks to complete. The most exclusive and intricate designs are those produced in Ban Tha Sawang, costing tens of thousands of baht for a single sarong.