Your browser is not fully supported. Please upgrade your browser.

Skip to main content
Textile Innovation

Filling the Gaps


Given its natural ability to insulate and protect, wool is perfect from the inside out. We report on the fibre’s latest application.

When New Zealand-born explorer Sir Edmund Hillary mounted Everest in 1953 ahead of his record-breaking achievement of being the first person to conquer its peak he did so wearing wool. The ascent was a feat of Kratosian strength. In vignettes of his journey, some of them lovingly coloured by modern technology, Hillary sits on snow beds with a sweet grin, as if to mock the mountain’s purity, or the societal tremors below. Sweaters, jackets, mitts, scarves and caps – all made, lined, or trimmed with wool fibres – hide his exhausted face and glassy gaze. Hillary reached the summit, about 8.85km above sea level, at 11:30am local time.

He and his climbing companion, Tenzing Norgay, spent just fifteen minutes at the top of the world. Hillary photographed Norgay yielding his ice axe, festooned with flags representing Great Britain, Nepal, India, and the United Nations. The sky is coloured by insinuations of blue, sonorous and stormy like a Turner painting. The two men dug a small hole in the snow. Hillary placed a crucifix inside, while Norgay left an offering of chocolates to the gods. Hillary never got his photograph taken at the summit, but it’s with partial thanks to the insulating properties of wool that he made possible what others had found beyond human limits.

In subsequent decades, oftentimes cheaper-to-source materials replaced wool as the primary ingredient in winter garments, including the quilted kinds, like those worn on challenging outdoor expeditions. Yet beyond the negative environmental impact of the synthetic alternatives – polyester, that which is used in the filling of many puffer jackets on the market, for example, derives from plastic, and at the end of its lifespan, will resist biodegradation in landfill – wool has been shown to offer better warmth per unit weight.

With thanks to its natural stretch and crimp – the way that, under a microscope, the fibre is tightly zig-zagged rather than straight – it creates many insulating air pockets, offering protection against the cold. And because of its inherent breathability, wool maintains a dry condition, creating a drier and more comfortable microclimate. This, of course, in combination with wool’s lightweight nature and odour-resistance, not to mention it being both biodegradable and renewable, means that the resultant garment rivals any synthetic alternative. “In many ways, it makes perfect sense that wool should outperform man-made fibres,” says Julie Davies, The Woolmark Company’s General Manager of Processing Innovation and Education Extension. “A sheep wears its fleece throughout the course of a year, during which time it endures rain and shine, cold and warmth, wind and humidity, and yet it thrives. Humans have known of the benefits of wool for centuries, and that we are seeing a remarkable return to natural and renewable fibres is evidence that nothing else is better.”

Deriving from the bedding industry, and with manufacturers in Australia, Germany, the United Kingdom and China, wool filling comes in varying forms depending on the style and form of the garment, including layered sheets, almost like wadding, and small balls, which can have the effect of moving to better fit the body in the areas where warmth is most needed. German outdoor brand Ortovox has long embraced the natural benefits of Merino wool, and its ‘Dufour’ jacket – named after the peaks, high above the clouds, of the highest mountain in the Monte Rosa massif of the Alps – is no exception. Part of its Swisswool Light Pure line, the ‘Dufour’ jacket is known for its excellent weight-to-warmth ration, meaning that despite being incredible lightweight, as well as easy to wear and pack, it packs a punch when it comes to insulating your body even at the coldest extremes. That it is ergonomically cut for extreme sports – armholes are edged with elastic, while two front pockets are designed for a map, radio or phone, and trail bar – gives further reason to its popularity by the most elite of climbers and explorers.

Smartwool, an American sportswear brand that prides itself on its use of wool and clear supply chain oversight, uses Merino wool in the filling of many of its mid-layer pieces (certainly not to mention its extensive range of wool base layers). Its SmartLoft range is geared specifically for arctic adventures, providing technologically advanced thermoregulation in the coldest, wettest and windiest conditions from one of nature’s oldest fibres. The ‘Double Corbet 120’ hooded jacket, for example, is a cold weather favourite of mountaineers, providing the ultimate warmth through next-to-skin Merino wool lining (the lined hood makes all the difference when the temperature drops) and 75% wool fill, including insulation in quilted panels down the front, back and sleeves. An added benefit of wool, of course, is its odour and moisture management, ensuring the longevity of the garment.

When the Everest climbers arrived in Britain after their successful descent, Hillary was embraced in beatific manner as a citizen of the Commonwealth. He wore a slate wool suit, middle button done up, which made a slight taper at his waist (he lost four stone during the Everest expedition). His apotheosis was marked by looks that were patrician but pliable, a long face and determined chin. The image was put on the New Zealand five dollar note. He was the first living New Zealander so honoured, and he joked that he would have to remain respectable for the rest of his life.

In 1999, Sir Edmund Hillary appeared on BBC in a black wool suit of disarming ministry, his face furrowed and washed by vertiginous weathers. “I really had no conception of the impact this was going to have on my life, or the media, or the world,” he said. “I remember standing on the summit and looking over another great mountain named Makalu, just across the valley. Even standing on top of Everest, I was thinking ahead to the next challenge.” Whatever the gods were up to that day, he had them beat dressed in wool.

Mitchell Oakley Smith is The Woolmark Company’s Global Content & Creative Manager. His writing has appeared in Architectural Digest, Belle, GQ, Harper’s Bazaar, Interview, The Australian and Vogue, and he is the author of five books on art, fashion and design.