Silk's Sustainability Under Scrutiny

Silk's Sustainability Under Scrutiny

Whether used for bedding, upholstery, or clothing, silk has achieved a reputation for luxury like no other fabric. Traditionally reserved for royalty, silk has often been associated with wealth and prosperity, and to this day, silk’s valuable properties are highly regarded throughout the fashion industry.

Lately, however, silk has been in the spotlight for less glamorous reasons - often being referred to as an unsustainable or unethical fabric. What might be less commonly known is that silk is produced in many different ways, each with varying degrees of ethical and sustainable credentials.

In this article we explain a bit more about where silk comes from, the different production methods involved and shed some light on the scrutiny surrounding its ethical and sustainable practices. 

Where does silk come from? 

The Mulberry Silkworm

The journey from thread to fabric has humble beginnings: starting with the domesticated silkworm, or Bombyx morias as it is scientifically known. This lowly caterpillar spends up to six weeks munching solely on mulberry leaves until it has grown 10,000 times its original weight.

Once fully grown, the silkworm uses two special salivary glands to produce a sticky solution, a combination of a liquid protein called fibroin, and a natural gum called sericin. Once the sticky substance comes in contact with air it solidifies and forms a silk filament, which the silkworm then uses to spin a cocoon around itself over the course of two to three days.

Infographic showing the life cycle of the Silkworm


The birth of sericulture

Legend has it that silk was discovered completely by accident: around 2700 BC in ancient China, Chinese Empress Leizu (also known as Xi Ling Shi) was sipping hot tea under a Mulberry tree, when a silkworm cocoon fell into her cup - the cocoon disintegrated in the hot liquid, and began to unravel. With a gentle tug, Empress Leizu was left with one long, unbroken strand of silk.

Upon sharing her discovery with her husband, the Yellow Emperor Huangdi, they proceeded to dedicate a grove of mulberry trees to monitor and learn about the life cycle of silkworms. It is believed that she created both the silk reel and the silk loom, both of which are tools used in the art of sericulture as we know it today. 

Silk Production Methods - Ethics & Sustainability

Traditional Mulberry Sericulture

Contributing to around 90% of the world’s silk, Mulberry silk is known for being the finest, most luxurious silk you can get. To produce the highest quality mulberry silk, the silkworms must be fed clean and dry chopped up mulberry leaves, and watched closely around the clock for signs of parasites, or disease that could threaten to wipe out the entire group.

A bund of silkworms eating Mulberry leaves

Source: Monikaninker - Getty Images

Once the cocoons have been spun, they need to be kept in warm, dry conditions for just over a week, after which they are then either steamed, baked, or dipped into hot water, a process that removes the sticky sericin from the silk fiber. 

Expert fingertips ‘tuft’ the side of the cocoon to reveal the end of the thread, and then delicately spin each thread whilst the cocoons unravel. Each cocoon produces one single thread of silk, that on average measures up to 1,000 yards of silk filament. In terms of weight, it takes approximately 2,500 cocoons to produce one pound of raw silk, and 1000 pounds of raw silk to make one dress.

'2,500 to 3,000 cocoons are needed to make just one yard of woven silk fabric'

The biggest producers of silk are found in China, India and Vietnam, where sericulture plays an important part in some of the local economies in these countries.

Traditional sericulture methods that include boiling, steaming or baking the cocoons, kills the silkworm in the process. The main reason for this is that if the silk moth is allowed to exit the cocoon, it secretes a fluid that damages the silk filament, which in turn shortens the silk thread, vastly reducing the value and quality of the fibre.

The killing of the silkworm is why, today, sericulture is often referred to as an unethical practice and in recent times a form of silk production, known as 'Peace Silk', where the silk moth is allowed to emerge from its cocoon, has been established. 

Peace Silk

Peace Silk, also referred to as Ahimsa silk, is known as a non-violent type of silk whereby the silkworms are allowed to emerge as moths, and only then are the discarded cocoons used for silk production. This does result in a lower quality silk, but the process is more peaceful….or so it sounds.

Silk worms emerging from their cocoons

Source: Naramit - Getty Images

It’s worth noting that just because a silk moth is allowed to emerge freely from its cocoon, it doesn’t mean it goes on to live a normal and happy life: the Bombyx mori silkworm has been domesticated over a number of centuries, and as such, they emerge deformed, unable to fly or eat, and are totally unaware of predators. 

The reality is that they spend what remains of their short lives (around 3-5 days) either in captivity being bred for the next batch of eggs, or they are discarded (i.e. released in to an incompatible ecosystem or killed). Many companies using this method will use ‘peace silk’ as a marketing tool, without divulging what actually happens to the silk moths.

Beauty without cruelty India, an animal rights organisation, have concluded that ahimsa silk is actually not peaceful, as the end result is still death and suffering:

‘Each and every punctured cocoon used for this so-called “Ahimsa Silk” or “Ahimsa Peace Silk” or “adhyatmik silk” represents suffering and death of one moth. It is no different to conventional silk for which each cocoon boiled also represents the death of one life.’

 It’s also important to be aware that although something might be labelled as ‘peace silk’, this is not a reflection on a brand’s ethical practices: like any large scale production facility, ethical issues can be prevalent, including child labour, long working hours, and low pay. Just because a brand uses ‘peace silk’, it doesn’t mean it is an ethical company.

Large-scale Commercial Sericulture

As is the case with most fabrics, silk is now mainly produced on a commercial scale, within large sericulture farms (well....factories!), with the majority being based in China and India. The production methods haven’t changed much from traditional sericulture, however, much of the silk processing now takes place inside large warehouses, meaning industrial climate control is needed so that the temperature and humidity is ideal for silkworm rearing. 

Silk cocoons drying at a silk factory in Vietnam

Source: Micia Anka - Getty Images

The sustainability of silk made negative headlines in 2018 when the Higg Materials Sustainability index (MSI), which measures the environmental impact of apparel production, ranked silk higher than virtually all other fibres. This was due to its carbon footprint, thanks to the high energy use needed in commercial silk factories for climate control, reeling and processing as well as large amounts of water used when harvesting silk from silk cocoons. 

The two major flaws we see with the MSI rating for silk is - 1) A very small data set was used for the ranking and was from just one low technology silk production factory in India, which is unrepresentative of silk production in general and 2) The ranking assumes silk is only produced in commercial factories, which is obviously not the case. 

The sustainability of large-scale commercial silk should be clearly separated between low-tech (higher energy use) and high-tech (lower energy use), as well as from other less energy-intensive sericulture methods, such as traditional community sericulture practices.  

Community Sericulture

Community sericulture is traditional silk production on a small scale: local community groups come together and practice the art of sericulture - this provides financial stability for small, rural villages, and as a result, families and communities thrive. 

The practice of small-scale sericulture also plays an important part in preserving local traditions and customs, as the methods have not changed in centuries, being passed on through generations.  

Two Thai ladies boiling silk cocoons for the harvesting of silk

Source: Pha Toomthong Silk

Here at Rare & Fair we have partnered with small-scale silk community providers, as we believe this to have the most all-round positive impact, environmentally and socially. As avid supporters of local economic and community success, we find that community silk production is beneficial to both the land and the people:

  • Water usage is kept to a minimum as producers only use what they need and then recycle the waste water after use. 
  • Breeding silkworms and handweaving silk provides financial stability for small rural villages, reducing migration to larger cities
    • According to the International Sericulture Commission, the silk industry provides employment to 20,000 weaving families in Thailand
  • Silkworms are a popular snack within the community, and so after the silk is harvested the silkworm’s life is not in vain and is eaten by the household or sold at the local markets, creating a low-waste, circular economy.
  • Mulberry trees are a multi-use crop and used by the communities as forage, firewood, fruit and tea, as well as in silk production.

Wild Silk

Rather than farming silkworms, the process of using wild silk involves waiting for wild silk moths to fly away, and then collecting the empty cocoons scattered throughout the trees.

There are many different types of wild silk, depending on the moth species, the region and climate that they live in and also the plants that they eat. Their freedom in diet means the silk varies in colour, from honey tones to deep browns, and the fabric can be much coarser and less lustrous than mulberry silk.

Given its sturdy nature, wild silk is a popular choice for curtains, bedding, and sometimes jackets or coats, but it’s used less in clothing, although it can be found. If you are interested in silk that is purely vegan, then this would be a great option for you.

Wild Silk cocoon hanging from a leave in Madagascar

Source: HHelene - Getty Images

Other Notable Types of Silk (other than Mulberry)

Eri Silk

Eri silk is produced by the Philosamia ricini, a silkworm that feeds mostly on castor leaves, and is found in the Northeastern region of India. In addition to the Bombyx mori, it has also been domesticated for the purpose of silk production.  

Eri silk is also often referred to as ‘peace silk’, or ‘Ahimsa silk’ - as the production process usually involves the moths being allowed to emerge on their own accord.  

Tasar Silk

Tasar silk, also known as tussar or tussah, refers to the ‘wild silk’ that we have mentioned above: it’s collected from the discarded cocoons of a variety of wild silk moths that live, eat, and breed freely on the local trees. Predominantly found in India, they can also be found in China, Japan, and North and South Korea. Unlike the domesticated silkworm, these wild silk moths, or Bombyx Mandarina, have continued to thrive in the wild.

Muga Silk

The largest producers of Muga silk can be found in Assam, India. Here, the semi-domesticated silkworm Anthereae Assama, which thrives mostly on the leaves of the som and soalu plants, is known for producing silk that is durable and glossy. With its unique golden sheen, this high quality silk is a popular choice for the traditional dress of Assamese women, the Muga Mekhela Chador.

Final Thoughts

Our opinion, if you are strictly vegan or just someone who wishes to avoid animal-derived products in your clothing, then any type of silk produced through sericulture, whether it be traditional or peace silk, is not for you.

However, if like us, you are of the opinion that harvesting insects can be an important part of a sustainable future for the planet, whether as a protein source or natural material, then we feel community silk is a great sustainable choice. 

In fact, we feel that community sericulture, with its low energy input, low water use, biodegradable material and circular economy, is one of the most sustainable fibre choices around. 

When choosing silk products, the most important thing is that you know what you are buying - as we have said before, ask questions, and look for transparency within a brand; this will help you to make purchasing decisions that align with your own personal values.

What are your thoughts on silk production? Share them below or get in touch directly, we always love to know if you think there are ways we can improve or do things better! 


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