In the world of base layers, there is the majority of fabrics that do a pretty good job of keeping you dry and temperature regulated. Most do one of these very well, and the other suffers. Then there’s merino wool. This mighty little fiber has been used, and prized, for centuries for its soft properties and performance. When most of think of wool, we typically think of scratchy sweaters and annoying winter socks from our childhoods. Merino couldn’t be further from that old, tired standard. Chief among its characteristics are the fine fibers – performance grade apparel is spun from fibers that are less than twenty-four microns (many brands use even smaller fibers) in diameter.
What does all of this mean for you? Merino is light and airy, so it breathes and wicks incredibly well. Additionally, healthy merino fiber has microscopic pockets of dead air in the strands and fibers of wool itself, trapping heat better than any other natural fiber. Finally, merino sheep naturally secrete lanolin into their wool, giving it antibacterial and moisture shedding properties over its lifetime.
Naturally, we wanted to really dig into performance of a good light weight merino versus our favorite waffle grid fleece and synthetic base layers. After doing a little digging on different fabric weights (see our recent base layer round-up), fits, and our use for hiking and climbing, we settled on Smartwool’s NTS Micro 150 for the fall shoulder season here in Salt Lake City and the surrounding Wasatch Mountains.
The NTS base layer’s 150 weight fabric means it is 150 gram per square meter. This is much lighter than a similar synthetic. We were originally a little apprehensive about this, but after a few outings, it proved us wrong. Layered under a light wind shell, the NTS base layer was warm by itself down forty degrees. When the sun came out or we were up in aerobic heart rate zones, that light, airy feel paid dividends in wicking – even when soaked from hauling forty pound loads of rope and gear uphill we were often dry within minutes of stopping. Additionally, the natural anti-stink properties were nothing short of amazing. At one point I didn’t wash my top for almost two weeks just to see what I could get away with. I wore the shirt to the office, on trail runs, and around town. Nothing. My favorite synthetic tech t-shirt would start to pick up a funk after a single gym session, and the merino just kept on rocking day in, day out. Performance? Check.
Like all merino, Smartwool’s microweight fabric has its drawbacks (albeit few). Merino doesn’t hold its shape very well when soaked, so can hang and stretch a little bit when pushed to the limit. It can soak up nearly thirty percent of its weight in water or sweat though, so you really have to be pushing hard to reach that threshold.
Our only real concern was with abrasion resistance. 150 weight merino is soft, almost to a “I am never taking it off again” degree, and that is actually the one drawback. Abrasion resistance is not stellar – but with such a lightweight fabric, it wasn’t designed to be. We’re really reaching for straws to find fault here, but it is a consideration for other users, especially if you’re going to use it in hard environments like hunting or climbing.
For what it’s worth, in a few weeks of wearing them almost daily climbing rough granite and limestone, we only created a couple tiny snags in ours (didn’t tear through at all, just ripped a stitch or two) and that was definitely due to abusing it. If layered properly you’ll easily get years of use.
Merino is one of the few materials we can honestly say is for everyone. Regardless of your sport, your environment, and how hard you abuse you apparel, Smartwool has something in their arsenal for you. The NTS 150 base layers have replaced a few sets of older synthetic pieces, and have converted us to merino and Smartwool for the foreseeable future. If you’re looking for a year round performance top or bottom, there are very few companies or products that can compete with Smartwool.
To learn more about Smartwool’s NTS 150 base layers, please visit their website. Prices ranges from $75 to $80. You can also check out the Men’s top here and Men’s bottoms here. The Women’s top can be found here and the bottoms here.