What the Heck is Merino Wool Anyways? Bah, Bah, Base Layers 101


There seems to be no end to the base layer choices for today’s outdoor enthusiast. The fundamental characteristic of any good base layer material is that it wicks moisture, i.e. it moves the body’s moisture away from the skin and creates a drier layer of insulation to keep you warm and snuggly. One option, Merino Wool is currently exploding in popularity. Merino wool is famous for its softness, warmth and odor control, but it's not cheap. What is it exactly and is it worth your investment?

From Socks to Tops: Wet and Cold is Miserable, Warm and Dry is Awesome.

First off, let’s be clear about the terms “base layer” and “wicking.” A base layer is the layer of clothing actually touching your skin (which includes socks BTW). By far the most effective way to stay warm in cold weather, regardless of how hard you are working, is to combine at least 3 layers of clothing as a base layer, an insulating layer and an outer layer. Hard shells, soft shells, and rain jackets make good outer layers because they repel wind and rain, but usually don’t offer much warmth by themselves. Gortex jackets are truly amazing, but while they will keep you dry, they won't keep you very warm. Goose down, fleece, wool and other synthetics can provide much better insulation. Combined with a good waterproof outer layer you'll be a lot better off. But the piece of clothing that arguably makes the whole system work together is the base layer against the skin.


As we all know, the body sweats to cool itself during periods of exertion. When your sweat evaporates it draws heat from the body, which cools the skin. Which is great, except when it’s cold, because the minute you stop exerting, you start freezing. Quite literally. The cooling action of your sweat will quickly make life miserable and could even lead to hypothermia or death if not dealt with quickly.

An effective base layer will "wick" the sweat away from your skin along millions of microscopic fibers that work a lot like the wick of a candle drawing wax into the flame. The moisture moves up the fibers and evaporates away from your skin instead of on it. This way you get to keep your body’s heat when you need it, but as you cool down, a damp layer of sweat doesn’t leave you wet and cold, or worse, heading for hypothermia.

Nature’s Wicking Fiber: Merino Wool

Since we humans aren’t very furry creatures (in most cases), we have to make stuff like coats and jackets to keep us warm in winter. Nature, however, has genetically equipped many species with all the wicking and insulating capacity they need to thrive in some of the harshest cold weather environments on the planet. Among the most blessed in this regard are the hardy Merino Sheep.


The Merino is a gutsy beast domesticated long ago because its wool is long, luscious and soft. A premium luxury item in Medieval Europe, Merinos flourished in Spain and N. Africa for centuries, eventually finding their way to N. America, Australia and New Zealand (where they became major export industries in the latter). Merino wool’s softness comes from how incredibly fine its fibers are. Thicknesses range from 24 microns across to as fine as 12 microns. By comparison a human hair is about 75 microns thick. At 1/6 the thickness of a human hair, some of the finer merino wools can feel silky-soft when milled into cloth.

Fiber Isn’t Just Good for Your Diet

Fine fibers yield fine yarns and modern textile manufacturers have flocked to the Merino in recent years to produce premium high-performance base layers, socks, and outer garments. The finer the fiber, the higher the thread count one can achieve in the manufacturing process. High-end Merino wool products pack more threads per inch into the garment than regular wool, significantly increasing the comfort, quality and lifespan of the garment.

Merino wool feels softer against the skin without the itch of cheaper, traditional wools, but still possesses wicking properties that rival any synthetic fiber on the market. With a high weight-to-warmth ratio, Merino wool can absorb water and still retain its insulating properties, unlike cotton. And as an organic fiber, merino wool also contains antibacterial lanolin which reduces body odor and multiday stinkiness (a big benefit for you sweaty peeps out there). With socks especially, you can imagine how that would be a very nice thing.

The downsides can be cost. Merinos are raised, fed and sheared more or less by hand, while synthetic fibers come from chemical-industrial processes that are far more cost-effective to scale. But for the outdoor enthusiast looking for a sustainable, natural product with uncompromising high-performance, it’s a great option. In my experience some synthetic fibers can dry faster than merino of a similar weight, but that has a lot to do with the quality of the wool. I can personally vouch that there is a very wide range of quality in products that claim to be Merino wool. Basically it boils down to the quality of the wool and the manufacturing. The finer the wool, the higher the thread count, which means a higher warmth-to-weight ratio, better moisture wicking properties, and a more durable product. Which, yes, is usually reflected in price. You do get what you pay for.

For socks, there simply is no comparison. Merino wool makes the best socks in the world which I've written about elsewhere on this blog. For me, there is no substitute.

So if you’re looking for comfort, high-performance and an all-natural product that will last, Merino wool is an excellent investment for any outdoor activity.

Jason Dudley