Why Is Wool Warmer?
When fighting against the cold winter weather of places like Chicago, Detroit, and of course New York City, staying warm at all times is a must. So what do we do? We go out and buy thick and heavy coats, scarfs, hats and socks; every essential garment needed to survive the brutal cold. But one may ask what is the number one go to protector? WOOL! But why wool? Why are we naturally drawn to wool? Why is wool warmer?
For centuries it has been instilled in our subconscious that wool is warm, but why is this particular fiber warmer than others?
Woolly sheep were introduced into Europe from the Near east in the early part of the forth millennium BC. The oldest known European wool textile, ca. 1500 BC, was preserved in a Danish bog. During those ancient times, selective breeding took place and the result were sheep with superior fleeces which required special care. Great to understand where this fabulous wool that we love and appreciate so much comes from, but it still haven't answered the million dollar question, why is wool warmer? Wool has several qualities and characteristics that distinguish it: it is crimped, it is elastic, and it grows in staples.
Because of the crimp, wool fabrics have greater bulk than most other textiles and they hold air which causes the fabric to retain heat. When you spin wool fibers into yarn, you get a lofty, resilient yarn that wants to trap films of air and keep it from moving from your skin.
Wool retains heat, and traps air like instillation for a house, for example; a fabric that's brushed to bring up a nap, like flannel, will keep more still air against your skin than one that is not napped, like muslin. Makes so much sense why punk/street wear enthusiast love wearing flannels during the fall. It's not because of Kurt Cobain like most of us thought, but because it's really warm.
Warmth from a wool also depends on the construction of the yarns. A closely woven fabric of a "cool fiber" can be warmer than a not so closely woven fabric of a "warmer fiber". A textured weave may be more retentive than a plain weave. Like a wool crepe may retain more heat than a looser plain weave wool. For the most part, wool garments are constructed with two basic weaves: the plain weave and the twill.
Woolen yarns are made into fabric using a plain weave which produces a fabric that is somewhat looser in construction and a soft on the surface. Worsted yarns can create fine fabrics with exquisite patterns using a twill weave. The result is a more tightly woven, smooth fabric. Better constructed, worsteds are more durable than woolens and therefore more costly. After weaving, both worsteds and woolens undergo a series of finishing procedures including fully immersing the fabric in water to make the fibers interlock which in turn retains more warm air.
So when battling the frigid, cold, brisk weather of the winter seasons, bundle up in wool and keeping warm won't be an issue. Use a wool challis as a base layer; it is light weight and it will help with moisture management unlike cotton which stay wet and might actually steal heat from your body.
All in all remember what we learned at Mood; when it comes to the number one question, "why is wool warmer", it is because wool flannels are way cooler than cotton flannels! Which is true in some cases, but the real reason is that wool holds more warm air and releases moisture better than any other fiber available.