Merino: everything you need to know

Merino wool is very curly, so the fibres lie loosely on top of each other and trap a lot of air. Depending on the fabric, it can consist of over 80 percent air. Nothing but hot air? In a way, yes. These countless air chambers ensure that Merino wool provides top-notch insulation. They’re where your body’s heat accumulates, which is why Merino clothing keeps you warm. When you sweat while wearing Merino clothing, moisture gathers in these air chambers and evaporates, cooling you down.

Finally, Merino keeps you warm even when it’s wet, unlike many other insulating layers. For example, down loses its insulating ability in damp or wet conditions. Merino, on the other hand, still keeps you warm until the fibres are completely sodden. Why? Because energy is released when the fibres come into contact with water molecules. The wool therefore not only insulates but actively produces heat.

Clothing made from Merino wool is naturally breathable and moisture-wicking, meaning that it draws sweat away from the skin. This helps you stay dry and feel less cold, even when you’re doing strenuous activities. In hot temperatures, Merino clothing keeps you comfortably cool due to evaporation.

Merino wool fabric inhibits odours for a number of reasons:

• Bacteria do not adhere well to its fine fibres.

• Merino wool wicks moisture away from the body quickly. This prevents any bacteria from breaking down the sweat and, in turn, forming unpleasant odours.

• The fibre protein keratin, which Merino wool naturally contains, also has an antibacterial effect. It absorbs bacteria and viruses and stops them from multiplying.

Merino wool offers UV protection. However, the extent of this protection depends greatly on the fabric’s thickness. A factor of 40+ is possible, but the value is lower for a lightweight T-shirt.

The fineness of wool fibres is measured in micrometres, i.e. thousandths of a millimetre. The unit of measurement is called a micron. Very fine Merino wool is about 15 to 16 microns thick, medium thickness wool is 17 to 19 microns and thicker variants up to 24 microns. For comparison, a human hair measures about 30 microns – highlighting just how fine this is.

Wool from other breeds of sheep is about twice as thick as the wool from Merino sheep. These fibres do not bend when they come into contact with the skin, so regular wool sometimes feels scratchy. Merino wool, conversely, is so fine that the fibres are able to bend and therefore do not irritate the skin. Merino fibres are also very long, which makes it more comfortable and ensures it feels pleasantly soft on the skin. It’s a different story with short fibres: they stick out and the garment feels scratchy.

Merino clothing works well as a base layer, i.e. as a first layer, directly against your skin. This is why thermal garments are often made from Merino wool. But if you’re wearing a Merino jumper, for example, make sure you wear something underneath that is also breathable. This could be made of Merino wool, too, but synthetic fibres are also fine. This ensures that temperature exchange and moisture dissipation take place continuously. Cotton is not suitable because it absorbs a lot of moisture and only dries slowly.

Merino clothing’s temperature-regulating and moisture-wicking properties best come to bear when it fits closer to the body. The fabric is soft and elastic, so it does not constrict your movement.

That depends on how sweaty you get. As a general rule, clothes made of Merino can be worn for several days. Merino wool has anti-odour effect and wicks moisture well. Airing out Merino clothing overnight helps leave it fresh again in the morning. Washing sparingly also extends the lifespan of your Merino clothing. Merino underwear is therefore ideal for lengthy trips or outdoor activities where you’re travelling light and don’t take many spare clothes with you.

Merino wool has impressive properties: it wicks moisture away from the body, is anti-odour and anti-bacterial. Clothing made of Merino therefore gets much less smelly than, say, synthetic clothing – even after several days of trekking or after long bus journeys. It is also soft and comfortable on the skin. Whether Merino is right for you and your adventure is a personal decision.

The number indicates the weight of the fabric in grammes per square metre. So, the lower the number, the lighter the fabric, and the higher the number, the thicker and heavier the fabric. The usual weight classes for Merino are 120, 150, 200, 260 and 320 grammes. The first two are lightweight and are usually used for shirts or summer clothing. 200 grammes is suitable for year-round wear. 260 and 320 grammes are thick and are perfect for winter and low temperatures. Due to the thickness of the fabric, they can trap more air and therefore provide better insulation than thinner versions. Thicker fabrics are also better if you’re carrying a heavy backpack, as they are more resistant to friction.