How Is Silk Made & What Ethical Alternatives Exist?

A short history lesson on silk

Silk has been produced in China since the stone age, and has been discovered in 8500-year-old tombs, along with the tools used to weave it.

Chinese legend tells the story of the young wife of the Yellow Emperor, Xi Ling-shi, who discovered silk when a silkworm cocoon fell into her tea.

Knowledge about the production of silk was a well-kept secret in China for centuries and led to a powerful monopoly that helped fund empires; silk was so integral to Chinese culture that legends of silk deities date back thousands of years – some are even still worshipped today.

The Silk Road was a network of trade routes that brought silk from China across Asia, the Middle East, Africa and Europe. Remarkably, China managed to maintain control of silk production for almost a thousand years more.

So, this is a material that’s been the inspiration for some of the earliest forms of globalization and has contributed significantly to the rise of one of the greatest powers of the modern world – it’s much more than just a fabric.

It’s been a product of legend, elite fashion, and vast economic significance for millennia. And as tastes change to reflect environmental concerns, people are starting to consider this biodegradable, natural fabric in a different light.

What is silk used for?

Raw silk is a common material produced by a number of arthropod-like insects and spiders. It’s a structural thread used for webs, cocoons, transport, and protection within the animal kingdom.

The vast majority of the world’s silk comes from a single species of moth larva: the domestic silkworm, Bombyx mori.

Silk moth caterpillars create cocoons made from silk that are insulating, lightweight, breathable, and resistant to microbial infection.

These properties are great for an animal’s larval stage in terms of safety, and equally good for producing a shiny pillowcase that doesn’t make you sweat.

But there are other uses for silk outside of fashion:

• Biomaterial: silk stitches have been used since 600 BC, and more recently, silk is being explored to stimulate bone growth and tendon healing.
• Parachutes: silk’s lightweight but sturdy nature made it ideal for parachutes until recent synthetic alternatives became available.
• Gunpowder storage: for high explosive powders, silk provides a static-free, spark-proof carrier

The majority of silk produced, though, goes into expensive clothing and household fabrics like bed sheets. Silk floss is also a thing, but there are definitely less controversial ways to make floss.

Some popular benefits to silk include its biodegradability, the low impact of its farming, and the fact that the industry provides valuable income to rural communities in many of the regions it’s produced.

How is silk made?

The caterpillar of the domestic silk moth produces a single strand of fiber up to 900 meters long, which it wraps around itself as it prepares to metamorphose into an adult moth.

This silk is finer than the finest of human hair, and has a very high tensile strength. Typically, silk is obtained from unraveling these cocoons – but some research suggests that drawing it directly from the caterpillar could produce tougher silk.

The moth lays its eggs on mulberries, which are planted solely for silk production. One hectare of mulberry trees is enough for only 90 lbs of raw silk, which loses about a third after processing. Around 1 metric ton of leaves is needed for a bit more than 50 lbs of silk.

After pupating, the cocoons are collected and placed in boiling water to dissolve the adhesive gum that holds them together. Like most animals, silk moth pupae don’t do well in boiling water and this step quickly ends their lives.

From here, the cocoon is unraveled, spun, washed, and often dyed; producing lustrous fibers of strong silk ready for weaving into fabrics. Silk is also often chemically treated to boost its sheen and add more weight.

Is silk ethical?

The major ethical considerations in silk production come down to the role of the animals involved, its social impact, and its environmental impact.

Social impacts

As with the fashion industry as a whole, silk production is riddled with cases of child labor, unsafe working conditions, and unpaid work.

It’s also a potential source of poor health – even for those compensated fairly. Silk workers often suffer from coughs, blisters, eye problems, and headaches, among many other symptoms.

Silk production can also be done safely, and it brings significant income to new communities as the trade gradually expands out of Asia into other parts of the world.

Environmental impacts

Silk is entirely natural and biodegradable, both of which are appealing buzzwords for the environmentally conscious, and the mulberry base for the silkworm does seem to be eco-friendly in terms of its maintenance.

These factors do depend on where it’s produced, however. In the African nation of Malawi, the high price and scarcity of silk is one of the key factors in maintaining its sustainability as a valuable crop.

Silk also uses much more water than cotton, and almost all of this water relates to the production of the mulberry leaves needed for the caterpillars.

In economic terms, there’s often more value in this expensive process than the equivalent in even rain-fed food crops, as long as the water requirements stay within reasonable amounts.

So these high water and land requirements make it less efficient to produce than low-value food crops or cotton, but silk’s value makes it a potential driver of development in areas that desperately need it.

Cruelty towards insects

The most glaring issue of all is the boiling alive of little animals for high fashion, but before talking about the ethics of silk making, we should consider some basic ecological and biological principles.

Firstly, let’s take a look at reproduction. Silkworms, like most insects, fish, some mammals, and numerous other animals use the scattergun approach to reproduction; laying a huge number of eggs in the hope that a few will survive.

Natural ecosystems actually rely on the early demise of most of these offspring. If every egg survived, the population would quickly overwhelm the environment, eat all the food, and die off.

An entire species dying off would mean the disappearance of an important food source for the other members of the community. Essentially, silkworm harvesting – in which the majority of worms are killed and only a few reproduce – is mirroring what would happen naturally.

This is the cruelty inherent in nature.

Whether this cruelty outweighs or justifies our own is part of the debate. But, even if our cruelty was found to be more than what would occur naturally, liberating the domestic silkworm is no longer a viable solution.

Silkworms would go extinct without us

Domestic silkworms only exist in captivity.

While this is also true for domestic cattle and pigs, there are a couple of stark differences. The domestic silkworm, having been artificially selected by humans for thousands of years – is now dependent on us for survival.

The silk moth can no longer see or fly, and cannot exist in the wild; it’s a captive animal in a symbiotic relationship with humans.

Humans get silk, the silk moth gets to pass on its genes. Whether it’s a good deal for the moth, however, is debatable:

• Are we increasing net suffering by harvesting silk?
• Does silkworm dependence on humans justify their existence and consequent exploitation?
• How does silk production compare to things like bees making us honey?

An interesting and controversial topic, similar to the ethics of zoos; but one solution may be to just harvest silk from abandoned cocoons – and that’s what some people are already doing.

Ahimsa silk

Ahimsa, or peace silk, is produced from wild species of silk moth cocoons that have already served their purpose.

The moth has emerged, continues its life as an adult, and dies naturally, usually within about a week. This silk is still produced on farms from moth larvae, but it doesn’t involve the hot soup stage for the pupa.

As a result, the cocoons are damaged when collected, and make shorter fibers. But, the animals live about an extra week before succumbing to the cold fingers of a natural death.

At least, most do. These are still farms, and a certain percentage of moths die in production no matter what. Since ahimsa silk is lower-yield, more moths are needed, muddying the ethics even further.

Wild silk

Since various different animals produce silk, multiple choices exist when it comes to harvesting it in the wild.

In Madagascar, wild silk from a completely different species of moth makes a thicker fabric than that of the domestic Asian equivalent.

Even invasive species spin silk, like the Box tree moths invading Europe and North America, where they feed exclusively on ornamental shrubs.

As a biodegradable material, and one that uses relatively few toxic pesticides and fertilizers to produce, silk may be one of the greener options for high quality clothing (aside from the mass killing of insects).

Research into more species of silk-producing, native species could also help sustain local habitats while providing communities with a source of income that comes directly from the protection of these habitats.

As silk becomes more valuable on a global scale, incentives to protect natural forest habitats for these moths increase, reducing deforestation and providing a valuable ecosystem service, similar to the financial boon of ecotourism.

These incentives may also protect a declining species, bringing its population back to healthy levels.

But of course, all of this still relies on animal products, so where do we go if we want a plant-based alternative?

Silk alternatives

Silk has some pretty unique properties that are hard to come by in nature.

The domestic silkworm was chosen for its silk from a plethora of animals capable of producing similar materials, so issues with attaining the uniform sheen that customers expect are common.

This makes it unlikely that any alternative will perfectly replicate silk’s quality. Silk alternatives generally sacrifice either quality, efficiency, or both. And with the impact of silk production being so difficult to pin down, it’s hard to know which is best.

Each substitute comes with its own appeals and drawbacks, and there are several to look into:

Bamboo silk

Bamboo is a super popular sustainable material currently, and it remains to be seen whether it’s a fad or can actually be made into a sustainable resource.

Either way, it’s popular for its resemblance to real silk and the similar feel of garments made from it.

Orange silk

Made from the by-products of citrus juice processing, this vegan option is one that many are touting as a cruelty free alternative to animal silk.

Orange silk is one of many cellulose-based alternatives recently hitting the market, with a goal of reaching the quality of moth silk.

Cotton

This biodegradable, plant-based material product is a sustainability minefield, requiring substantial amounts of water, monocultures, and pesticides to produce.

With cotton crops using 10% of the world’s pesticides, the debate of replacing it often revolves around which option doesn’t, and whether these options create the same benefits to communities as silk could.

Hemp

Hemp fabric continually rates highly in sustainability comparisons for its durability, low cost of production and low environmental impact.

Compared to things like cotton, hemp needs considerably less water, pesticides, and energy to grow and spin into thread; but the hemp industry simply hasn’t been in the spotlight long enough for widespread adoption.