What Makes Icelandic Wool Unique – and What Is Lopi?
For centuries, wool has played a key role in the lives of Icelanders. Long before modern outdoor clothing existed, people in Iceland relied on wool to protect themselves from the cold and wet climate of the North Atlantic.
One of the most well-known products made from Icelandic wool is lopi, the material used to knit the traditional Icelandic sweater known as the lopapeysa. Lopi is special because it is unspun, which allows it to trap a large amount of air and create garments that are light, warm, and breathable.
But what exactly is it that makes Icelandic wool – and lopi – so unique?
The answer lies in three things: the Icelandic sheep, the structure of the wool itself, and the long tradition of wool craftsmanship that has developed in Iceland over the centuries.
A Sheep Shaped by 1,100 Years of Isolation
When Viking settlers arrived in Iceland in the 9th century, they brought sheep with them that were essential for survival. Over more than a thousand years of isolation and in a cold northern climate, this flock gradually developed into a unique breed: the Icelandic sheep (Ovis aries borealis).
Today there are around 400–500 thousand sheep in Iceland, slightly more than the human population. Most are kept on small family farms where sheep farming has long been an important part of rural life. Because importing sheep into Iceland is prohibited, the Icelandic breed has remained genetically isolated for more than 1,100 years.
During the summer months the sheep roam freely across Iceland’s mountains and valleys. In autumn they are gathered from the highlands and sheared before being brought indoors for the winter. Shearing usually takes place twice a year – in spring and autumn. The highest quality wool typically comes from the autumn shearing, after the sheep have spent the summer grazing on mountain vegetation and living outdoors.
Throughout Iceland’s history, sheep played a vital role in sustaining the nation. Wool was just as important as meat and was used to make clothing, blankets, and many other everyday necessities.
The Icelandic sheep has a dual-layer fleece: long outer fibres called tog that protect against wind and weather, and soft inner fibres called þel that insulate and retain warmth.
Icelandic Sheep – Wool with Two Different Types of Fibres
The wool of the Icelandic sheep has a dual-layer structure:
tog, which protects against wind and weather, and þel, a soft inner fibre that insulates and retains warmth.
The Secret of Icelandic Wool: Tog and Þel
What makes Icelandic wool truly unique is that it consists of two different types of fibres. Only a few sheep breeds in the world have this dual-fibre structure.
The outer layer is called tog. These fibres are long, relatively coarse, and strong. They are naturally water-repellent and help protect the sheep from wind and harsh weather.
Underneath lies þel, which is short, fine, and soft. The þel fibres are crimped and do not lie tightly together, which allows them to trap a large amount of air.
Because the fibres are so different, they can be separated – something that was commonly done in earlier times. The soft þel was often used for garments worn close to the skin, while the stronger tog could be used for items such as rope.
Today, however, the fibres are usually processed together. This combines the best qualities of both: warmth and weather resistance. Together they create the unique properties of Icelandic wool, which protects the sheep from the elements just as effectively as the traditional Icelandic lopapeysa protects the people who wear it.
Because of this structure, Icelandic wool provides:
- excellent insulation
- good breathability
- lightness
- natural water resistance
What Is Lopi?
Lopi is wool that has been washed and carded but not spun into yarn.
During processing the wool is first cleaned and then passed through a carding machine where the fibres are drawn into soft continuous strands. These strands are called lopi.
Lopi can therefore be seen as an intermediate stage in wool processing, between carding and spinning. If the process continued further, the fibres would become spun yarn.
This loose structure makes lopi:
- lightweight
- airy
- exceptionally warm
Because lopi is unspun, it is lighter and airier but also more delicate than traditional yarn and should therefore be handled with care. However, this is also part of its strength. Because it contains so much air, lopi traps heat extremely well and insulates better than many other yarns.
When knitted, the fibres tighten and lock together, making the finished garment both warm and durable.
The different qualities of tog and þel working together make it possible to knit directly from unspun wool. This is very rare elsewhere in the world, where wool is typically spun into yarn before knitting begins.
Plötulopi – Unspun Icelandic Wool Used for Traditional Sweaters
Plötulopi is unspun lopi that comes directly from the carding machine. It is commonly used to knit traditional Icelandic lopapeysur.
Plötulopi is unspun Icelandic wool that comes directly from the carding machine. It is used to knit many traditional Icelandic lopapeysa sweaters.
Why Lopapeysur Are So Warm
Many people wonder whether lopapeysur are waterproof. The answer is no, but they have properties that make them particularly effective at retaining warmth in cold and damp weather.
Wool is naturally water-repellent and continues to insulate even when it becomes wet.
In Icelandic wool, the tog fibres help repel moisture, while the þel fibres trap warm air inside the garment. The loose structure of lopi further increases the amount of air in the knitted fabric and therefore improves insulation.
For this reason, lopapeysur have long been popular among fishermen, farmers, and outdoor enthusiasts.
The Origin of the Icelandic Lopapeysa
The classic Icelandic lopapeysa is actually a relatively modern tradition. Research suggests that the sweater took its modern form in the 1940s, when knitters began making sweaters from lopi with the now-familiar circular patterned yoke.
The lopapeysa does not have a single designer. Instead, it gradually developed through the work of many Icelandic knitters who adapted patterns and designs to suit the qualities of Icelandic wool.
During the 1950s and 1960s, the patterns continued to evolve. They were influenced by Scandinavian knitting traditions, which Icelandic knitters adapted to work with lopi. This process eventually led to the sweater design we recognize today.
The popularity of the lopapeysa grew rapidly during the 1970s and 1980s, and today it is one of the most recognizable symbols of Icelandic craftsmanship and part of Iceland’s cultural heritage.
Because of the growing demand for lopapeysur – especially among international visitors – the Icelandic lopapeysa became a protected designation in 2020. This ensures traceability and confirms that the sweater is made from Icelandic wool and hand-knitted in Iceland.
Wool That Connects Past and Present
Today Icelandic wool is still highly valued for its unique properties. It is not only warm and durable, but also carries the story of the land and of the people who have worked with it for centuries.
It connects nature, craftsmanship, and culture – from the sheep roaming freely across Iceland’s mountains and valleys to the knitting needles shaping the garment stitch by stitch.
Every skein of lopi carries the story of the country itself – of the sheep, the landscape, and the craft tradition that has developed here for more than a thousand years.
Sources
The information in this article is based on historical and scientific research on Icelandic wool, sheep farming, and traditional wool processing in Iceland.
Key sources include:
- Ístex – The Icelandic Wool and the Icelandic Sheep
- MAST – The Icelandic Food and Veterinary Authority
- National Museum of Iceland – textile and wool history resources
- Icelandic knitting and textile research on the development of the lopapeysa
- Historical sources on Icelandic sheep farming and wool processing traditions
Curious about how this tradition continues today?
Read the story of how Icelandic wool — and the desire to preserve this historic resource — inspired a group of women to start a movement to protect and teach traditional wool craftsmanship at the Þingborg wool workshop, where the story of Hörpugull begins.