Eri silk: new in Thailand

Thai silk is famous throughout the world for its beauty and texture. Most of this silk is created by a variety of silkworm that eats only mulberry leaves. Eri silk -- produced by the Eri silkworm, which feeds on different foods than the Mulberry silkworms -- has its origins in Assam province in India and is relatively new to Thailand. Eri silk combines the elegance of silk with the comfort of cotton and the warmth of wool. Eri silk can be spun evenly or unevenly into fine threads or coarse yarns, making it a perfect fibre to create interesting textures.

Eri silk was introduced in Thailand by researchers at Kasetsart University in Nakhon Prathom (in Central Thailand), but the Fai Gaem Mai (Cotton and Silk) Program of Chiang Mai University's Institute for Science and Technology Research and Development (IST) is largely responsible for helping spread Eri silk production to villages in the North and Central regions of the country.

The Eri silk project, one of a number of projects run by Fai Gaem Mai, involves several villages in four changwats (provinces). We were invited to visit Ban Panasawan, "Forest of Paradise," one village where all the steps of production take place: raising Eri silkworms, safeguarding cocoons, releasing pupae, boiling empty cocoons, fluffing, spinning, dyeing and weaving the yarn into beautiful textiles.

In Ban Panasawan, there are 20 households participating in the production of Eri silk:
- 25 women raise worms;
- many women are becoming adept at spinning silk yarn;
- group members together dye the spun yarns when required; and
- 4 women weave.

The women in the village already had Mulberry silk skills -- passed from mothers to daughters for generations -- including skills in natural dyeing, so it was a good fit for the Eri silk project. They continue to create Mulberry silk and now work with Eri silk to create a textile with a new and exciting future.

While Mulberry silkworms eat only mulberry leaves, Eri silkworms are content to munch on the byproduct of one of Thailand's most important agricultural products: cassava (also called tapioca). The production of the root, used principally as an edible starch, occupies more than 1.5 million hectares in Thailand. That leaves a lot of leaves for Eri silkworms, giving cassava farmers new opportunities to bring in additional income from the production of Eri silk textiles.

Residents of Ban Panasawan, like other villages chosen for this project, have been successfully growing cassava for many years. They have reached a level of production that is able to sustain most community members; this has reduced migration to urban areas. However, as cassava is a low value/high volume commodity, the additional employment and income to be derived from Eri silk production appeals to the many women who choose to join the group. Not needing to plant a special crop of multerry, they could use the cassava leaves to feed the hungry Eri silkworms, then top off their diet at the end of the growing cycle with castor leaves (used in some regions as the exclusive food for Eri silkworms). This helps the Eri silkworm produce a bigger cocoon, richer in silk content.

The Fai Gaem Mai project provides training on caring for Eri silkworms, coordinates the stages of production that often involves several villages and helps with marketing. Fai Gaem Mai is also working with international designers to bring a wider range of products and techniques to these village women. The objective is to interest a wider range of consumers, both within Thailand's urban centres and internationally. These days, daughters are attending school longer to reach higher educational levels, so a school program has begun to teach them about the history and cultural role of silk in Thai society, with the aim of interesting more young people to pursue these production skills.

The eggs for the project were initially provided by Kasetsart University, which does sericulture research, but now the entire cycle from eggs through to moths is undertaken in the village. We learned that:

1. Eri silkworms are larger (and uglier, in the opinion of many Thai women who raise Mulberry silkworms!).
2. They are hardier than Mulberry silkworms, and are easier and less expensive to raise.
3. The Eri cocoons are larger than the Mulberry cocoons and are white in colour, in contrast to the native Mulberry cocoons, which are bright yellow. This offers a white yarn for weaving and dyeing.
4. Like the native Mulberry silkworms, the Eri silkworms can produce generation after generation; this is in contrast to the hybrid and foreign varieties of Mulberry silkworms, which can only reproduce for 2 generations. This makes the Eri silkworms ideal for self-sufficiency, as they can reproduce for multiple generations.

We were taken to different homes in the village to observe the various stages of production. We learned that Eri silkworms have a 45-60 day cycle: the worm eats for 25 days, during which it goes through five stages of growth, molting at the end of each stage, where it sheds its skin; it then spins its cocoon, made up of triangular protein segments, where it spends 15 days, transforming from a worm into a pupa before it emerges from the cocoon as a moth. After 3 days the moth will lays eggs, which, after 10 days, hatch into worms -- and the process begins all over again.

The Eri cocoon is quite different in another way from the Mulberry cocoon. The Mulberry silkworm cocoon completely surrounds the silkworm. It is made up of up to 300 metres of continuous protein filament that is "reeled" into a long thread. In contrast, the Eri silkworm makes its cocoon with short segments of protein, so it must be spun, like cotton or wool, into a long yarn, ready for dyeing and weaving. The Mulberry cocoon must be boiled to remove its filament; the Eri cocoon, open at one end, can be left intact so the moth can emerge through its open end, without damaging the cocoon, to lay more eggs.

Because the pupa (which later develops into the egg-laying moth) is not killed to remove its cocoon, Eri silk is sometimes referred to as "peace silk" or "vegan silk." In this village, as in many others, only some of the pupae are left to develop into moths; the rest are easily removed from the cocoon, and only later are boiled or fried for food. As well as providing an important source of protein to supplement villagers' diets, removing the pupae leaves a cleaner cocoon, made up of 100% silk, as none of the dry chrysalis and final stage of the worm's molted skin remain inside the cocoon. For those who prefer silk that is not produced by silkworms that must be killed in order to create the silk, Eri silk is an excellent choice.

Last but not least, the leaves upon which the worms eat, live and excrete are an important part of the sustainable cycle of production. Worm excrement is used as a fertilizer for vegetable gardens, and the waste leaves and stems of cassava are collected and composted, also for village gardens.

During our visit, we were able to observe all parts of this production process.

Eri silk spinning was of special interest to us because up until this visit we had only observed the production of hand-reeled Mulberry silk. The spinning machines introduced by Fai Gaem Mai for Eri silk production are made for this project by one manufacturer in Lamphun province in Thailand, but are based on a design developed in India by an appropriate technology NGO. The appropriate technology design uses bicycle rims and other common machine parts that are easy to replace when worn, and is pedal powered -- avoiding the need for expensive electricity, as well as leaving both hands free for spinning.

Currently, spinning is done in only one village, which limits the production of yarn. During our visit, five women were gathered at spinning wheels in the home of the village's project trainer. The women spun together and talked about ideas for the work -- a creative time for them, which they greatly enjoy. They told us that they want to further develop their spinning techniques so that they can spin yarns with varying thicknesses and textures.

Right now, the average production of yarn per person is about 200 grams per day; 1 kg of yarn can make 6-8 finished pieces (50 x 180 cm). The project is working to address this bottleneck in the production process.

As with the other groups we visited, participants in this project only use natural dyes. They plant dye materials and also collect them wild from the field. They asked us to remind our customers in Canada that natural colours will vary with location, season and even weather, so colours will always be unique!

The day we visited, these women were dyeing with tamarind bark. They told us that they've been taught by extension workers to remove only a section of bark so they don't kill the tree. The bark has been boiled for one hour before the silk is immersed, which is then boiled for about 30 minutes. One portion is rinsed in soda ash water to make the colour brighter (resulting in a shrimp paste pink), and the other in alum to make it more beige coloured. We were told that had they used iron phosphate as a mordant, the colour would have changed to gray.

Before returning to the van we arrived in, we had the opportunity to purchase a few finished scarves and table-runners as samples. We have since made an order for scarves and table runners, made from a mix of Eri and Mulberry silk, for sale in Canada -- most probably the first Thai Eri silk in our country!

Alleson and Ellen (Luk Nok)