Understanding Merino Wool

Named after a breed of sheep, merino wool is fast becoming the fabric of choice for many athletes and outdoor enthusiasts. No longer the itchy, scratchy wool of yesteryear, merino wool is composed of ultrafine fibers that are amazingly soft, breathable, and durable. This versatile fabric is now being used to make performance socks and base layers by brands such as SmartWool, Icebreaker, and Ibex. If it’s been a while since you’ve worn wool, here are some reasons to give it another try.

100% Natural

The product of happy sheep in need of an annual haircut, merino wool’s harvesting and processing requires much less energy than the manufacture of synthetic fabrics. Reducing your carbon footprint has never felt so good.

Temperature/Moisture Management

Wool is a uniquely versatile fiber that keeps you comfortable in both cold and warm conditions. Few other single fabrics work so well in such a broad range of temperatures.Merino wool insulates even when wet. This high-grade wool consists of naturally crimped fibers with tiny threads sprouting off them. The sheer number of thread surfaces is so vast that even when wet, wool fibers trap little pockets of air, which serve to insulate you. When dry, the number of air pockets increases, so the wool insulates even better.Miraculously, the same tiny crimped wool fibers that keep you warm in winter also keep you cool in sweaty conditions through the process of “evaporative cooling.” The many fibers act as perfect little wicks to pull moisture up off your skin, move it across the face of the fabric, and expose it to the outside air where it can evaporate quickly. These wicks are what make wool a better moisture manager than many other fabrics.


Because of its unique combination of insulating and cooling qualities, a midweight merino wool piece can negate the need to pack both lightweight and heavyweight synthetics for variable weather conditions.


Properly cared for, wool will last for years and is one of the most durable fabrics available. The naturally crimped spring-like structure of the fibers retains its shape after multiple seasons of use, and has much greater tear resistance than cotton and many synthetic fabrics.


Wool fibers are very resilient and snap back to their original shape, creating a wrinkle-free fabric that’s very travel friendly.


Because of the fibers’ coil-like springs that compress and expand, they provide natural cushioning. It’s this quality that makes merino wool an ideal fabric for socks.


Because wool wicks and evaporates moisture quickly, the individual fibers stay quite dry. This moisture-free environment helps prevent the growth of odor-causing bacteria, mold, and mildew.

Soft Texture

Again, wearing is believing. Slip on Icebreaker tights or a SmartWool top, and you’ll be amazed at the soft texture of merino wool. Forget cotton flannel. This stuff is silky smooth!

Flame Resistance

Often worn by race-car drivers to retard flames, wool offers much greater fire resistance than synthetic fabrics.

Caring for Merino Wool

Naturally shrink resistant, merino wool stands up to washing and drying much better than traditional ragg wool. Some garments, like socks, can be thrown into the washer and dryer with all the other laundry. On the other hand, knit tops need to be gently machined washed and then laid flat to dry. (Be sure to follow the care instructions provided with each product.) In any event, avoid bleach! It will yellow the wool, or worse yet, break down the wool’s individual fibers.


Founded by New England skiers who were trying to keep their feet warm, SmartWool was originally focused on creating the most comfortable shrink-resistant performance socks possible. The company now offers an expansive line of wool apparel, from boxers and tights to shirts and hats. CLICK HERE to see all of our SmartWool products.


A leading proponent of using merino wool as a performance fabric, this New Zealand company offers high-quality shirts, tights, socks, and underwear. CLICK HERE to see more.