You’ve probably got your truck, EDC bag, and rifle dialed in. You’ve spent enough time online researching your next camp stove or piece of titanium cookware to become a bona-fide expert. When it comes to sourcing gear for your latest adventure, there are boundless resources and reviews out there. What about your apparel? When it comes to picking base layers, hard shells, and everything else you need to stay comfortable in the backcountry, there are not that many real resources out there beyond marketing materials and hands on reviews. Sure, it’s great to see that the new Smartwool merino top wicks well and is warm, but how do you select a set of apparel for your given environment? Do you go with natural fibers or synthetic? What about soft shell vs. hard shell? What are the pros and cons as you build your apparel kit from the skin out?
Too often I see people out at local crags, on the ski slopes, and out on the trails woefully unprepared for the elements. Even worse, I see people over dressed to the point that they are degrading the performance of their $500 GORE jacket or ruining their day by overheating or staying sweat soaked for hours on end.
With that in mind, we would like to talk about layering from the skin out. Part One of this series will dive into base layer selection. Rather than just giving you a product to go out and buy, we want to educate you on what a base layer needs to do, the different materials that are used, and what to look for whether you’re on the trails in Alaska or hitting slick rock in Moab. We’ll also share our tried and true favorites for every season, so you can understand how we pick our own apparel systems for comfort (and survival).
Base Layer Guidelines
The primary job of a base layer is moisture transport. If your clothing can’t pull sweat away from your skin, you’re going to stay hot in the summer and cold in the winter. In effect, it should be a second skin that provides wicking and breathability when you’re moving fast or staying static. It’s important to note that not all base layers are created equal in this regard. You won’t be wearing expedition weight merino wool while heading out car camping in the summer, and that mesh t-shirt probably isn’t a safe bet for the ski slopes. Additionally, you want the cut and fit to be different depending on the environment (more on that soon). First, we’ll take a look at different materials.
Merino wool is a fine wool from merino sheep. It is naturally antimicrobial (think no stink), and wicks incredibly well. However, when used by itself and woven in light weights, it tends to lose its shape when wet and is easy to tear. To combat that issue, it is often blended with other fibers. Its wicking and breathability properties make it an excellent choice for all-season use, especially when woven with nylon or Tencel for hot weather applications.
Bamboo fibers are a new comer to the apparel world. Using a steaming and crushing process, inner fibers are removed from the hard outer core of some types of bamboo and spun into yarn. As an environment option, it has benefits in land use, water conservation, and biodegradability over other natural fibers. The fiber itself has a silky and airy feel, making it a good choice for hot weather. Blended with heavier synthetics, it can impart its excellent breathability into much warmer fabrics. It also absorbs more water than similar cotton fabrics, pulling moisture from your skin faster than almost any other fiber.
Tencel is a type of Lyocell fabric, which are fibers made from pulped and treated hardwoods. Specifically, Tencel is made from Eucalyptus. It is an extremely breathable fabric, especially when blended with merino and synthetic fibers. You’ll most likely find it in socks from brands like Farm to Feet and Lorpen, where their blends have been tested to wick up to three times fast than merino blends without it. Recently, Smartwool and Icebreaker have launched summer lines of apparel with Tencel that provide comfort above eighty degrees, where merino alone typically starts to get too hot.
Silk is typically a specialty lightweight fabric. While especially soft and light, it offers a good warmth to weight ratio. However, it is much less durable than almost any other fabric, often requiring hand washing and special attention to abrasion when you’re out on the trail. The trade-off is the luxurious feel. Silk is the best choice for picky skin and provides excellent wicking. It has fallen out of favor with the outdoor industry in recent years though, and with the advent of blends like Tencel, we don’t see it making a big comeback anytime soon.
These are your nylon, polyester, and other man-made fibers. Rather than relying on natural fiber construction, man-made blends can incorporate different fiber structures (along with natural yarns too). They tend to be durable for hard use situations, and can perform at a wider range of temperatures, but do not have any anti-microbial properties inherent in merino and bamboo. You’ll likely run across synthetic fibers when looking for Polartec fleeces, as well as just about any military surplus base layer.
Weight, Fit, and Other Considerations
Regardless of what fabric you go with, the most important part of selecting a base layer is finding one tailored to your needs. This is where knowing a little about fabric weight and performance comes in, but the most important characteristic is knowing your body. Most manufacturers label base layers (especially wool) in four categories:
- Microweight: Mild to cool conditions. Short sleeve versions of this are applicable for summer and warm weather travel.
- Lightweight: Cool, to moderate cold. We typically run lightweight during shoulder seasons, as well as sleepwear when camping at high elevation during the summer.
- Midweight: Moderate cold, to cold. These are the most versatile for high aerobic output in the cold (think snowshoeing, cross-country skiing, and hiking).
- Heavyweight/Expedition weight: Cold to frigid, especially when extreme windchill is a factor. Heavyweight systems tend to have extra loft beyond just a heavier fabric, and are an excellent option of staying static in cold weather.
Beyond weight, fit is the other key consideration. Typically, a tighter fit will wick better, as there is more direct skin contact. However, full compression style apparel (your Under Armour boxer briefs don’t count as compression) is usually inadvisable in situations when you’ll be wearing it for extended periods, as true compression gear is designed to stimulate blood flow to targeted muscle groups rather than aid in cooling. This can cause problems both in heat and cold. As long as your layering fits close to the skin, you will get all the benefits. In extreme cold, you may want a looser fit to trap more warm air. This is especially true when you spend long periods of time sitting in a tree stand, duck blind, or on a ski lift. That extra warmth you build up while exerting yourself will stay trapped and pay dividends for hours.
Finally, The last thing you need to think about is your use. What is the environment you’ll be in? A mountain town dweller is going to get more mileage out of a good lightweight merino than a desert rat. Do you want more than one season of function? Heavy weight wool or Polartec fleece is probably out for the summer camping crowd. How much do you sweat? Finding a fabric that wicks enough during aerobic activity, and dries when you need it to is worth more to me than another that might keep me a little warmer. In the end, personal preference trumps performance, so long as you fit your apparel to your activity. The last comfort touch? Smell. Are you backpacking or ski touring and need to save space? Pick something that will fight odors, especially if you’re going to be wearing the same set for a few days at a time.
When traveling in hot weather, we usually don’t even bring long sleeve and full bottom length base layers. However, it’s still important to have wicking – especially when hauling heavy packs on the trail or spending long days on crowded planes or buses in exotic places. We took a few pairs of our favorite Ex Officio Give-N-Go underwear on a trip to Thailand earlier this year. After two weeks of backpacking and hauling gear through multiple airports, and only rotating 3 pairs (one worn, one clean, one ready to wash/dry) they’ve become our go-to for comfort and staying dry when out in the backcountry. We added a Sport Mesh t-shirt to the mix, and haven’t looked back.
During shoulder seasons in the alpine it can be hard to have a one-size-fits-all apparel approach. One day we are climbing granite at 10,000 ft in summer temperatures, and the next afternoon our mountain bike ride dips into the 40s with frozen rain and hail. Smartwool’s NTS 150 weight merino is the perfect layering piece for year round endeavors. We use it to sleep in on summer camping trips, as a base layer on spring and fall summit days, and as an extra layer under a collared shirt in the office in the winter. If you’re really smart, you’ll get your better half a couple of the women’s line (the bottoms are especially comfortable under skinny jeans).
Extreme cold in the mountains calls for a little more loft. Polartec Power Wool fills every need for us when the mercury starts dropping. This bi-component fabric is woven so that soft merino wool sits in a grid pattern against your skin. This enables extra wicking, and more importantly trapped warm air. The outer face is a synthetic that is more abrasion resistant than wool, and aids in moisture transport away from the inner layer. We’ve been wearing Under Armour’s new Charged Wool line up during our late season climbs. The warmer fabric breathes like a much lighter polyester, allowing us to move faster hiking and climbing because we aren’t adding and dropping layers as much.