What is organic silk

About silk

Silk is a proteine fibre, made from the long fine threads (filaments) that are secreted by the silkworm (Bombyx mori), with which it spins before turning into a pupa. Before the caterpillar develops into a butterfly, the threads are unwound from the cocoons.

Silk is a luxurious natural product and has good properties that increase the wearing comfort. Silk fibres are temperature regulating, they feel warm in the winter and cool in the summer. The soft shiny fabric is very elastic, breathable, absorbent and well insulating. In addition, silk has a natural protection against dirt and does not need to be washed often. Usually, just airing it is enough. Silk is also fire resistant and hardly creases.

Silk can absorb a lot of moisture before it feels wet, up to a third of the weight of the fabric.

Organic silk

GOTS-certified silk also exists. It means that the fibres come from organic farming. This is always a regulated and certified method of sustainable land management with proven benefits for man and the environment. 

With regard to silk, organic farming mainly concerns the cultivation of mulberry trees and mulberry leaves which are used to feed the caterpillars. The GOTS certification does not only relate to the raw material used, but mainly to the way it is processed into textiles. This means that the entire production process of the fabric has been carried out conform the highest ecological and social standards.

In addition to organic silk, there is also 'peace silk'. While in the regular production process the butterflies are killed before they come out of the cocoon and before the filaments are unwound, in the so called peace silk the butterflies stay alive. However, this has consequences for the filaments, which are damaged by the butterfly emerging from the cocoon.

At the moment, the range of GOTS-certified silk fabrics and peace silk is very small.

Momme

Silk is the only natural fibre that exists in filament form, meaning that it doesn’t have staple fibres of several centimeters that always have to be spun into a yarn but long thin strands that can reach lengths of up to one kilometer! While these strands are strong, they are also very fine and can vary in thickness between cocoons, so thread count isn’t a reliable way to measure the weight of a silk fabric.
Traditionally the Japanese used a specific unit for measuring silk fabric density which was a modified version of a weight unit used to measure precious metals in the Edo period (17th-19th century): the Momme (abbreviated as ‘mm’). The momme is still used as the industry standard unit for silk fabrics and is equal to 4,34 grams per square meter.
 
A fabric that weighs a single momme doesn’t exist as it would be too sheer, but very lightweight and transparent fabrics range from 5 to 12 mm, with more medium weight textiles often falling around 16 to 19 mm, and dense luxury fabrics starting at 25 mm.
Yet this doesn’t mean that a higher mm always means better quality, it all comes down to the use case. Lightweight fabrics are more transparent and cool, ideal for clothing pieces that can be layered in the summer or need an additional lining; while heavier textiles tend to be more durable and opaque, more suited to bedding.