Whether for hiking, trekking or skiing, merino wool has established itself as a benchmark for outdoor activities. It offers unmatched comfort compared to synthetic fibres. But what makes it so special, and how do you choose the right piece? Cimalp reveals everything you need to know about merino wool.
The origin of merino wool
The emergence of merino wool
The history of merino wool dates back to the 12th century, when sheep originating from Asia Minor were introduced to Spain. For several centuries, it remained exclusive to the country and its wool was considered the finest in the world. In the 19th century, merino sheep were eventually exported to other regions with more favourable climates.
Current production
Today, merino sheep farming takes place mainly in Australia, which accounts for around 80% of global production, in New Zealand and in South Africa. However, they are found all over the world, including in France.
For several years now, animal welfare has been a core concern. Mulesing, a painful practice aimed at preventing parasite infestations in sheep, is increasingly called out. More and more producers now guarantee mulesing-free farming.
Merino wool is considered one of the best natural fibres for making outdoor clothing. Its fineness is exceptional, between 17 and 24 microns, compared to over 30 for standard wool. However, due to fibre quality and ethical production, its cost is higher compared to synthetic materials.
Characteristics of merino wool
Thermoregulation and natural insulation
Like any natural fibre, merino wool has its pros and cons. First, it offers thermoregulating properties. The fibres trap air, creating natural insulation. Garments keep you warm in cold weather while staying breathable when it gets hot.
Thanks to its unique properties, you can head outdoors in both summer and winter, without suffering from temperature fluctuations. Merino wool clothing can be worn all year round, especially during mountain activities where weather conditions change quickly.
Moisture and odour management
Merino wool is also renowned for its antibacterial properties. The keratin structure of the fibre naturally limits bacterial growth, which causes unpleasant odours. Merino garments do not need to be washed as frequently as synthetic ones.
Along with its anti-odour properties, it delivers great moisture management. It can absorb up to 30% of its weight in water without feeling wet. The feeling of dryness lasts even during prolonged exertion. However, it reaches its limits in very wet conditions. Synthetic fibres, like polyester, are more hydrophobic.
Comfort, softness and freedom of movement
The mere mention of wool often makes people with sensitive skin expect the worst. Contrary to popular belief, merino wool does not itch. Instead, the fineness of its fibre delivers unmatched softness.
Its fabric is also stretchy and moves with you. What's more, it is crease-resistant. Even after being folded or rolled up, it bounces back into shape, making it extremely practical for minimalist backpacks.
Lightweight, durable and easy care
Merino wool also stands out for its lightweight feel. Its fine fibres allow for soft, airy garments in any season. Despite their fineness, they remain surprisingly hard-wearing. The finest models do, however, wear out faster than synthetic fabrics, especially in high-friction areas.
Caring for merino wool is relatively simple. Modern garments are generally superwash-treated and are machine washable. However, take care not to use harsh detergents, which damage natural fibres, and avoid the tumble dryer. Instead, opt for delicate cycles and line drying.
Natural, eco-friendly and protective fibre
Merino wool is 100% natural and renewable. Its environmental impact is low, especially when sourced from farms that respect animal welfare. It is biodegradable and can even serve as fertiliser as it releases nutrients back into the soil.
Finally, merino is naturally flame-resistant. That means it doesn't melt, won't stick to the skin, and self-extinguishes if exposed to fire. This property makes it highly valued for bivvy trips and expeditions when wearing technical next-to-skin layers.
Which activities should you choose merino wool for?
Winter activities
One of the main strengths of merino wool is that it adapts to virtually all outdoor activities, all year round. Fans of winter hikes or high-altitude treks particularly appreciate it because it retains heat, even when damp.
In skiing, ski touring or snowshoeing, merino wool provides consistent thermal regulation. You won't overheat on the ascent and won't feel the chill on the descent. Its moisture management also prevents you from catching a post-effort chill.
In mountaineering, merino wool is often used as a base layer under technical shells. It creates effective natural insulation without weighing down your gear.
Mid-season activities
In mid-season, merino wool delivers adaptability and climate comfort. In autumn and spring, temperature shifts are frequent. It is therefore extremely practical for Nordic walking, light trail running or fast-hiking, staying breathable during exertion and insulating at rest.
In climbing, via ferrata or other mountain activities, merino wool ensures great freedom of movement. It provides genuine flexibility and natural stretch to those who wear it.
Summer activities
In summer, heat regulation and sweat management are essential. Contrary to what you might think, merino wool is not overly warm for summer hiking or hot-weather trekking. It wicks heat and sweat away and even provides UV protection.
It is also practical for bivvy trips, bikepacking or travelling as it is lightweight and compact. In this case, however, its main asset remains that it can be worn for several days without washing thanks to its anti-odour properties.
Finally, merino wool is also used in trail running or mountain running. Its excellent body temperature regulation makes it ideal for long outings.
How to choose your merino wool clothing
Fabric weight
Choosing merino wool clothing depends on your intended use and the weather conditions. Fabric weight or density, expressed in g/m², determines the warmth and thickness of the garment.
The higher the fabric weight, the warmer and more insulating the fabric:
- 150 g/m² or less: lightweight and breathable fabric, ideal for intense activities in warm weather.
- 150 to 200 g/m²: versatile use, ideal for mid-season activities.
- Over 200 g/m²: thick fabric, used as a thermal base layer during winter activities.
For versatile outdoor use, we recommend a fabric weight of around 180 to 200 g/m².
Composition
When buying your merino wool clothing, you can choose between 100% merino or a blend with synthetic materials such as nylon, polyester or elastane.
100% merino has the advantage of being ultra-soft, offering maximum breathability and being naturally odour-resistant. On the other hand, it is less abrasion-resistant and dries a bit more slowly. It is a great option for a base layer worn next to the skin.
A blend of merino and synthetic fibres offers the combined benefits of both materials. The garment delivers better durability and strength, dries quickly, and is lighter and more stretchy. However, it loses a little of the natural purity of merino. It is recommended for more demanding sports, and for intense or repeated use.
Garment types
Garment types let you choose each layer of your outfit. Merino wool thermal base layers are popular for their warmth without overheating and their lasting comfort. Long-sleeve tops and tights are therefore ideal for enjoying winter activities.
Merino wool t-shirts can be worn all year round. To make the right choice, opt for a fitted but not tight cut, and a light to medium fabric weight depending on the weather.
Mid-layers (merino jumpers, jackets or hoodies) are worn over a t-shirt or as a base layer, providing excellent natural insulation. Choose a higher fabric weight and a blend with synthetics for added durability.
Accessories like merino wool socks are also extremely practical. They keep your feet dry and odour-free. Once again, blends with nylon or elastane are recommended for extra durability.
Merino wool combines technical performance, comfort and respect for the environment. When buying, choose garments sourced from ethical farms and suited to your activity. That way, you'll enjoy durable comfort across every season.
