Following on from my previous entries, this post is in support of Campaign for Wool’s Wool Week 2021. In this post I will be diving in to the physicality of wool as a fibre and importance in the future of sustainable textiles.

A Physical Fibre

Wool is a versatile and fascinating material. A fibre comprising of three layers: the cuticle, cortex and medulla. Each of these layers contributes to the physical properties of wool, and each has an important role to play. The first layer, the outer layer consists of many tiny scales. It is these scales which dictate to us how the fibre feels. Its appearance and handle are influenced by the size and density of these scales. Fine wools such as Merino have tightly packed, tiny scales, which overlap one and another. This gives the fibres a softer feel, so it is less likely to itch and irritate skin. Coarser wools such as Jacob, have much larger and less densely packed scales. They are further apart and give the wool a much ‘scratchier’ feel. These scales also affect the lustre of the wool, controlling how the light reflects off of the surface and how matte we perceive it to be.

The middle layer of the Fibre, the cortex, influences the crimp of the wool. It is comprised of elongated cells formed in a helix, which determine how much crimp the fibre has. Crimp can alter the strength and elasticity of the fibre, two important qualities. Again, in fine wools such as Merino there is a tighter crimp pattern compared to the curly locks of long wool breeds. The crimp of wool fibres will trap air and give it insulating qualities. The cortex is also where absorbency of water vapour occurs, giving wool its fantastic property of being comfortable in both warm and cold conditions. Finally, in the middle, you can sometimes find the medulla, a channel of air. This causes fibres to be thicker and wiry. Wool fibres with a medulla are often referred to as ‘medullated’, it is a characteristic that has mostly been bred out, or if not, these fibres are removed in processing.

Cross section diagram of a wool fibre, Spin off magazine, 2010.

Britain has a long and rich history with wool. It rose in popularity in the middle ages, becoming the backbone of the economy (Johnson, 2014). All around the country, sheep’s wool held a high economic value as an important British asset. Yet with time its uses and popularity have steadily declined. The rise of popularity in Australian and New Zealand wool in the 18th century was a catalyst for its downfall. During the industrial revolution, the wool that towns were built on - such as Bradford, was imported Australian or New Zealand wool. Later in the 20th Century, its use declined even further with manufacturing moving to china and overseas. With modern innovations in materials and material processing, British wool has lost favour. It is not just British wool that has seen a decline. In fact, globally wool only makes up 1.2% of the total fibre consumption.

British wool is traditionally seen as coarser than wool from Australia and New Zealand, due to its higher micron count. There is a myth that it is only suitable for products such as carpets or insulation, with a heavy feel. Could this perception be just that – an assumption? Britain has more sheep breeds than any other country. How can we harness the material properties of these breeds to create a more diverse range of products from wool? While there are plenty of breeds which have a coarse wool such as Herdwick, Balwen and Welsh Mountain, there are also breeds that could be used to create softer wool, more suited to fine garments. For instance, the Ryeland sheep, which is thought to have originally developed in Herefordshire. It is also thought to have been derived from Spanish Merino, giving it a fine quality wool. Throughout time, the Ryeland sheep has been bred for its meat production rather than its wool quality. This has resulted in its value as food increasing but its value in textiles decreasing. This is also the case on a global scale. Wool is most often a secondary product to meat. Due to this focus, the quality of the wool is compromised. If we were to invest back into breeding sheep for their fleece, placing the value on the quality of the wool, its value in textiles would be increased. Such is the case of the Merino, which has long been the leader in quality of wool, due to its breeding for wool being prioritised over meat production. Also by taking a more breed specific approach to grading and using wool, the fine qualities of breeds such as Ryeland, could be used to broaden the landscape of British wool. In the last year there has been a significant rise in interest and championing of British wool and British sheep breeds, something that will hopefully continue to grow.

Left: Ryeland Fleece, Right: Herdwick Fleece

Wool is full of variation, the physical properties of the fibre are different in every breed. This variation is key to its future in sustainable textiles. Being able to harness its many different properties and use them to create textiles, gives a breadth of possibility in the end use of the textile. In Britain, we can use the vast range of sheep breeds to our advantage, to capture the individual traits and values of each fleece type. By taking a more breed specific approach to grading and using wool, the fine qualities of breeds such as Ryeland could be used to broaden the landscape of British wool. In the last year there has been a significant rise in interest and championing of British wool and the variety of British sheep breeds, something that will hopefully continue to grow. But to truly harness the individual properties of these breeds, there needs to be systemic change. Currently British Wool (previously British Wool Marketing Board) grades wool by its quality not by its breed. This way, wool of all breeds is blended together. Smaller, more localised systems would allow specific breeds to be graded separately. This is the case at places such as the Natural Fibre Company, in Cornwall. They spin fleece in to yarn in small batches, requiring only 20kg minimum, providing a valuable service to farmers with smaller amounts of fleece. Small mills and production could be the future of sustainable textiles, to truly recognise the value that the many breeds of British wool have to offer.

There are however physical properties in wool that are relevant in all breeds, that have a particular relevance to its role in sustainable textiles: it is biodegradable, and it stores carbon. When we consider a material in relation to sustainability, we must consider its whole life span. What will happen when products formed from the material are no longer wanted? It is no secret that the textiles and fashion industry generate large amounts of waste every year. Consumers also generate waste, with an estimated 350,000 tonnes of garments going to landfill in Britain every year. These figures show how important it is for designers and manufacturers to consider a material’s life from beginning to end. The material may not deplete resources when created, but it can add to an ever-growing problem of waste when it is disposed of. For the majority, the textiles industry creates products which are intended to be thrown away at the end of their lives, in a ‘Cradle to Grave’ model. Michael Braungart and William McDonough have long pioneered the idea of a ‘cradle to cradle’ model, in which products and materials are designed to be circular and to provide “nourishment for something new”. Wool is a circular material; it can be recycled, and it biodegrades. Using a material to its fullest potential is key when reducing its impact on the earth, when wool is returned to the earth, it releases stored carbon back into the ground. It is part of the natural carbon cycle and should be disposed of as such.

The physical nature of wool a a fibre means it can be easily broken down into its fibres and re-spun to create new products. It holds its value, allowing it to be used again and again. A leading force in wool recycling is the location of Prato, Italy. In this town, 15% of all the worlds recycled clothes are processed. Each business within the town is dedicated to one part of the process, working in harmony together. This is a fascinating example of not only how textiles can be recycled, but also how a town can thrive around one function. The recycling of wool boosts the economy of the town and region.

Of course, it would be better to recycle wool in Britain, creating a closed loop system, and to avoid the carbon emissions that inevitably occur from shipping wool around the world to be recycled. Recycling wool in Britain is possible. The yarn brand iinouiio have developed a recycled wool yarn, created in Yorkshire. They take discarded woollen garments from Britain, break them back down to the fibres and spin them into many different weights of yarn. It is excellent that the facility for recycling wool exists in Britain, this will strengthen the future of British wool. Innouiio are currently involved in a R&D Project in conjunction with University of Arts London, so it will be interesting to see how this develops further in the future. The ability to see wool through its entire lifecycle is important in its future in sustainable textiles.

If wool is not to be recycled, it is vital that it is disposed of in the correct conditions, allowing it to break down, releasing important nutrients and carbon back into the soil. This has been put to the test in recent years in an experiment with Campaign for Wool. Two jumpers were buried, one made from merino wool and one from synthetic fibres. After a four- month period, the jumpers were unearthed. The wool jumper has begun to degrade and decompose, while the synthetic remained entirely intact, as can be seen in the photograph below. In just four months, the wool jumper was well on its way to being naturally disposed of.

Biodegradability test, Campaign for Wool, 2014.

There is a danger that wool is sent to landfill, where the anaerobic conditions will not allow it to biodegrade. Consumers and manufacturers need to understand the material to make sure it is disposed of properly and that it can play its part in the carbon cycle. Wool comes from the land, and it must be returned there.

Understanding the physical make up of wool is important to truly understand its value in sustainable textiles. If we know how the properties of the material effect its relation to sustainability, we can make smarter decisions as consumers and designers.

Material matters

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