Merino wool base is naturally breathable, insulating and deodorant. They also have some very cool features, which can help you maintain a comfortable and appropriate temperature under various conditions.
Merino wool is much finer than other wool fibers. To become a "merino", the diameter of wool fiber must be less than 24 microns (about 1/10 of the width of human hair).
Natural ventilation
Merino wool is a living fiber that can adapt to your environment and body temperature. All natural fibers can absorb and desorb water, but wool is very good at it.
Wool does this by absorbing moisture into the structure of the fiber itself and then expelling it into the external air. This helps to maintain your temperature level in the same way as perspiration - evaporating sweat to cool you down when you overheat, and keeping your skin surface dry to keep warm when you cool down.
In fact, wool fiber can absorb up to 35% of its weight before it feels wet. When your base layer cannot absorb more water, its fibers will absorb water in the same way as synthetic fibers.
Temperature regulation
The breathable wool fabric can better control the evaporation rate than the synthetic fabric. When your body surface is hot and wet, wool will quickly release water from the fiber, and slow down when it is cold and dry.
When water molecules react with molecules in wool fibers, there is also an ingenious chemical reaction that will release heat. This can prevent rapid cooling when you really sweat after hard climbing.
Natural insulation
Wool fibers have natural waviness (or "curl"). When they are stacked together, a large amount of insulating air will be produced. The finer the fiber, the more waves, and the more cavitation. This makes fine merino wool have excellent thermal insulation and weight ratio.
Because Merino wool fibers are very elastic, they will not lose these air bags when wet, and can provide insulation even when wet.
In addition to skin comfort
Because Merino wool fibers are very thin, they are softer than standard wool, and no one will itch except the most sensitive skin. It is difficult to explain the reason, but Merino wool underlay is also more comfortable than artificial fabric.
And because the fiber can absorb a lot of water before the fabric starts to feel wet, the merino wool underlay rarely feels wet and cold on the skin - unless you are sweating all the time!
Natural deodorization
Wool has built-in deodorization function. Unlike synthetic base, it needs treatment like Polygiene to keep it fresh. By keeping the skin surface dry, wool first reduces the growth of odor that causes bacteria. However, wool will also capture odors in its fiber structure, and only release them when clothes are washed. Most importantly, the study also showed that compared with synthetic fiber, merino fiber provides less hospitable environment for bacteria causing odor.
Biodegradable
As a natural fiber, merino wool will be biodegradable under appropriate conditions, rather than staying in the environment for many years.
