Biologically termed as Ailanthus Silk moth, the silkworm responsible for Eri silk is generally found in China and Japan. They are also prominently found in south Asian regions, these Silk moths are predominantly found on the wild trees or shrubs of Shorea Robusta and Terminalia. 

‘Eri’ is derived from the Assamese word ‘era’, which translates to castor. This is because the silkworms that produce Eri silk feed on castor plants.

This kind of silk is woolly and rather less popular but has piqued the interest of many sustainable fashion enthusiasts as it is made without killing silkworms. Such a procedure being followed has led to the silk being called ‘Ahimsa silk’, a fabric of peace.

The caterpillar of samia ricini, a silkworm, is used to make Eri silk. Eri silk’s processing part is carried out by rural or tribal women and takes up to 45 days. North-East India’s humid weather benefits the making of this silk. The silkworm grows and feeds for at least thirty days before reaching its final size. It then spins its cocoon in short segments, taking up to fifteen days to completely spin and open. Through the opening, the moth escapes and the empty cocoon is boiled in water to degum. Shaped into small cakes, the cocoons are placed against mud houses to dry out. 

Once dried, these small cakes are spun to create yarn, which is then woven. The outcome of the production process is a strong and sophisticated Eri silk fabric that provides the comfort of cotton, and the warmth of wool.