by Corinna Elsaesser
Thoughts on Silk - Is It Sustainable?
Silk doesn’t only feel and look luxurious - it also has some great active qualities as a material. Silk is a highly breathable fabric that functions in two ways: keeping you warm in winter by retaining heat and cooling you down in summer when the temperature rises. Silk is 100% hypoallergenic, odourless and surprisingly durable.
So what's the story behind this much sought-after fabric?
Legend has it, a Chinese Empress named Leizu discovered the world’s most luxurious fabric while sipping tea under a mulberry tree. A cocoon fell into her cup and instead of removing it, she watched it slowly unravel. As the cocoon came undone she noticed that the entire pod was actually made from a single thread, durable but soft to touch.
This was the moment silk was born. Her discovery led her to create the silk loom, which is said to be around 5000 years old. Quickly becoming a major commodity, silk has since contributed to the development of international trade relations, leading to the creation of the trade route which later became known as the Silk Road. Established by China’s Han dynasty in 130 BC, the Silk Road connected China and the Far East with the Middle East and Europe.
But where do we stand today with this ancient fabric?
Mulberry Silk accounts for about 90% of silk production worldwide. Whilst China is still the biggest market for silk production, India follows closely in second.
Let’s take a closer look at the production process which to this day remains similar to the story of Empress Leizu.
It all starts with the Mulberry tree - silkworms feed on the leaves of the Mulberry tree, spinning themselves into a cocoon made from one single thread. In order to extract the silk from the cocoon, steam is used to remove the worm, leaving the single strand fully intact. The silkworms’ threads are then spun into a white or ivory silk fabric. Although highly efficient, this method gains criticism from some as it involves killing silkworms for the purposes of creating fabric.
However, some luxury fashion houses have been using so called ‘Peace’ silk - also known as ‘Eri’ or ‘Ahimsa’ silk - in their garment production. The difference to traditional silk is that the ‘Eri’ silkworms are allowed to emerge from their cocoon either through their natural hatching process, or in some cases through a man-made hole. The empty cocoons are gathered after the silkworm – now a moth – has left. This enables the silkworm to complete its natural life cycle, creating a much more sustainable way of harvesting silk threads. These ‘Eri’ worms also feed off castor leaves instead of mulberry.
There are some drawbacks to this method - the silk thread is broken during hatching, which means it must be woven back together to re-create the original single strand, and this can have an impact on the quality of the silk. Silkworms have also become highly domesticated over the years and may only survive a few days after they leave their cocoon.
As animal welfare is often a concern for ethical fashion companies, the use of silk can be a very grey area. Silk is generally considered to be a sustainable material as it produces almost zero waste and uses very little water compared to other fabrics such as cotton. Silk is also biodegradable – in the right conditions able to decay in just a few years - which is a huge advantage when compared to synthetic or mixed material garments.
So what is the solution if you want to wear sustainable silk, but are an animal lover?
In recent years many fabric development start-ups have emerged, producing silk-like materials made from plant-based materials such as rose petals, oranges, bananas or pineapple. These products remain biodegradable but do not require the disruption of animal life cycles to create.
Two start-ups in particular have been working on new silk technologies. Spintex Engineering, created at Oxford University, manufactures strong silk fibres which are spun from a water-based solution of dissolved silk fibres sourced from post-consumer waste. Bolt Threads specialises in so-called spider-silk, which is produced in a lab setting by fermenting yeast, sugar, salts and water, spinning the finished solution through a spinneret machine. Both companies have been working with big fashion houses such as Stella McCartney to scale up their operations and bring these materials to the mainstream market.
So, what is the conclusion on silk? When considering sustainability, we need to remain aware of how our choices effect animal welfare as well as the other human and environmental factors that often take center stage. Silk may not be the most creature-conscious fabric, but with new technologies emerging onto the market all the time, hopefully we’ll see a cruelty-free version of the material coming into the mainstream in the near future.