Originally Posted by elcruxio

The thing with wool is that like with any material, you need to know how to use it and what its properties are to effectively get the best use out of said material.

Wool is a natural fiber and like many natural fibers, it sucks up water. However it holds water in a way that it stays warmer than many other materials even when wet. But it still does absorb quite impressive amounts of water and as a natural fiber it dries really slowly when comparing to synthetic materials like coolmax or lycra for example.

Now while sport synthetics do get wet, they don't absorb the water into the fibers themselves like natural fibers do. This effectively means that synthetics dry and wick moisture quickly. The problem comes when there's no place for said water to go, ie. it can't evaporate or transfer to other layers and hence the water stays on the fabric making the person wearing them uncomfortable in the process.

This is why layering is important. You use a wicking layer (synthetic) as base and the absorbant natural fiber (wool or sometimes cotton) as mid or top layer so the moisture is removed from the skin surface and it still has a place to go. An old hiking tip from our challenging conditions is to use something extremely absorbant as top layer, such as cotton, and remove that immediately after stopping. That way you'll remove a lot of the moisture you've created by just removing a garment and don't have to dry up nearly as long.

Years of outdoors experience have convinced me that wool really isn't a good base layer next to skin. It's much better to use a synthetic to wick the moisture onto the wool or other natural fiber than to use the natural fiber as skin layer and have that moisture against the skin constantly as the garment slowly dries. Because wool really dries slow and even though it warms you even when wet, it's not nearly as good at it while it's dry, or when comparing to a dry synthetic.