Originally Posted By: Art_in_FL

But when I ran into this statement:
"After absorbing moisture, chemical reactions take place in its fibres releasing heat and as result making the fibre feel warm against the skin."

The assertion that the fibers release heat is a very questionable. Feeling warm does not mean the wool is generating actual heat any more than drinking alcohol 'makes you warmer'. more likely the ability of wool to irritate skin just feels like warmth.

Wool has some slight advantages in some situations over most polypropylene fleece because the fiber density, and weight, on the wool is higher and it is water repellent because of the lanolin in the fibers. Not so much because of some magical "pores". Wool is not Gortex. But a lot of it is how the clothing system is driven.


These are actually well documented properties of wool and some of the many amazing properties of the stuff.

Wool is naturally water repellent because of it's microscopic structure and because of the wax within the fibers. In the right situation, water will bead off. This structure also allows vapour to freely pass through the fibers...so in this way it is sort of like Goretex.

Wool will also absorb moisture. Because under normal circumstances it will try to repel the water and absorb the vapour, it generates heat because water vapor being forced back into a liquid form is an exothermic chemical reaction which generates heat. Wool can also absorb up to 1/3 it's weight in liquid.

This is also what keeps us cool in the heat when the opposite happens. We sweat and the wool absorbs that moisture and wicks it away from the skin naturally, then it evaporates...an endothermic reaction which absorbs heat effectively cooling us. These are the chemical reactions he's referring to.

Now that being said, in this case they've soaked the wool forcibly by dunking it in water so they've bypassed this effect (wool is water repellent, not water proof). I think the warmth they are feeling is what was left of their own body heat. Wool will wick the moisture away very quickly and as it does, the insulating properties of the wool will be restored somewhat.

Also, I'm with you on the synthetics. For the most part I like poly and similar materials better because of their durability. But as a base layer wool is amazing. I wear the same Merino tops and bottoms in the cold (silk weight) under insulated clothing as I do in the summer when it's +35C...I can't do that with Poly...I'd roast. I wear poly layers over top of that base layer for added effect and it seems to work really well.

My guess on why they wore Cotton was a worse case scenario test.