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How We Tested Base Layers

Saturday November 12, 2022

We tested base layers in both real-world situations and did specific tests in our lab, allowing us to provide comprehensive and in-depth reviews. From dragging these layers up chimneys on desert towers to skinning up volcanoes in the Pacific Northwest, we run these tops through the gauntlet. Below is how we test for each metric.

base layer - canyoneering in utah, the patagonia capilene air breathed well...
Canyoneering in Utah, the Patagonia Capilene Air breathed well keeping us from overheating in temps in the 60s but didn't stand up to dragging it through sandstone slots.
Credit: Roland Mott

Warmth


This one is simple. We wear each base layer in really cold conditions — alone and as part of a layered system — and we see how efficiently they keep us warm when temperatures drop into uncomfortable ranges. From long nights under the stars to backcountry ski days, our tested base layers have seen it all.

base layer - taking a breather from the lung-bursting skin track in frigid dawn...
Taking a breather from the lung-bursting skin track in frigid dawn temps.
Credit: Adam Zagorski

Breathability


We use a combination of real-life experience as well as regulated tests for this metric. We skinned up mountains, hiked talus cones to climb desert towers, pedaled steep mountain biking trails, and ran winding mountain trails in Colorado. In the lab, we test each top, one at a time, in a temperature-controlled, indoor environment — we work up a sweat with the same short but rigorous exercise routine and then time how long it takes for our skin and the inside of our shirts to dry after stopping.

base layer - breathing it out up a classic front range climb before a heavy snow...
Breathing it out up a classic front range climb before a heavy snow is forecasted to start in the next few hours.
Credit: Roland Mott

Comfort and Fit


We wear these layers a lot, and with an extremely critical eye. We consider the comfort of the fabric of each layer next to the skin. We compare the way they fit on testers of different body types and examine the stitching patterns and design features. We record the length of the torso and arms, judge how comfortable the collar is, comment on the stretch of the fabric, and note specific features like a drop-tail hem, tapered arms, and thumb loops. We critiqued how they form to the body, whether they bunch up when layered, and made notes on when they become uncomfortable during strenuous activity. If our testers find themselves wanting to wear a layer all the time, then that is a sure-fire way to know that a particular product has climbed its way to the top of our list.

base layer - coffee and oatmeal - two things you don't leave your bag before...
Coffee and oatmeal - two things you don't leave your bag before having in your hands. Having the perfect fit for your base layer for these mornings and the adventures that lay ahead is crucial.
Credit: Roland Mott

Durability


This is another combination of thoughtful observation both while at play and in a controlled environment. We beat the heck out of these things — we drag them up desert towers, scrape through slot canyons, and bushwack through thickets. We also send them through repeated wash and dry cycles to see how well they hold up under more normal circumstances and note what tends to break down fine fabrics the fastest.

base layer - putting the icebreaker 200 oasis to the test dragging it up a...
Putting the Icebreaker 200 Oasis to the test dragging it up a squeeze chimney on an obscure desert aid climb. Being 100% Merino wool, we were impressed with the Oasis.
Credit: Kricket Servis

For our lab test, we take a section of the fabric at the elbow and vigorously drag it back and forth against a 1-foot piece of rough and textured sandstone to see how the fabric holds up to abrasion. This test provides us with a clear picture of what fabrics will stand up to abrasion over time and which are simply not built for such rigorous activities.

Even though the 100% Merino wool 250 g/sm is heavy weight for a base...
Even though the 100% Merino wool 250 g/sm is heavy weight for a base layer, our harsh abrasion test ripped right through the fabric.
Our harsh abrasion test barely put a mark in the tough synthetic...
Our harsh abrasion test barely put a mark in the tough synthetic fabric.
Abrasion testing reveals a lot about which layers are best suited to certain activities

Drying Speed


The time a base layer takes to dry while next-to-skin and the time it takes to dry away from the body can vary significantly. First, we note a layer's ability to dry next to the skin through activity, working up a sweat while mountain biking, trail running, and skinning. As a laboratory test, we completely saturate each top and lay them flat to dry in the sun. This test simulates hand-washing and drying out a piece of clothing like you would on an extended backpacking trip or expedition. Conveniently, the timed results often correlate directly with a top's ability to dry on the body efficiently and provide us with specific times to compare the products with one another.

base layer - tops during the drying test.
Tops during the drying test.
Credit: Roland Mott

Layering Ability


We incorporate each top into any and every layer combination we can imagine. We observe how they feel against the skin and how well they layer with different clothes worn over the top. We layer tight and sticky technical fleece mid-layers, wool sweaters, slick nylon down jackets, and tacky synthetic insulating layers. Any combination we can think of, we try out.

base layer - a handsome layering system with the rei co-op merino as the base...
A handsome layering system with the REI Co-op Merino as the base, Patagonia R1 for a mid layer, and the Outdoor Research Transcendent Down Hoody as the outer insulating layer.
Credit: Roland Mott

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