Colorado performance-fabric maker Voormi claims that shirts made from its new Dual Surface UL fabric—a synthetic/merino wool hybrid—are the lightest and most wicking merino-based products available. To test that claim, we packed only this shirt for a three-day backpacking trip through Washington’s Enchantment Basin.
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Merino provides excellent next-to-skin comfort in both hot and cold conditions by regulating body heat. It’s soft, like cotton or synthetic fabrics, but unlike cotton it doesn’t soak up water, and unlike synthetics, it doesn’t get stinky. But that doesn’t mean it can’t be improved. For a while now, purveyors of merino performance clothing have been trying to boost its hot weather appeal by making it as lightweight as possible. And, to boost its durability and wicking ability, people have blended in synthetic fibers, too.
Voormi claims to have not only brought to market a substantially lighter weight merino fabric, but by blending in a “razor thin” layer of synthetic fibers next to the skin, it's the most highly wicking as well.
Fabric weight is measured by how many grams a square meter of it weighs. Typically, you’ll find ultralight merino shirts in the 125 to 150 g/m2 range. Hell, I’m wearing a 125-weight shirt right now: it’s comfortable even while doing active stuff in the heat. Icebreaker’s lightest merino shirts are 130 g/m2 and SmartWool’s are 150 g/m2. Voormi's new Dual Surface UL fabric, on the other hand, weighs just 100 g/m2. And you can feel the difference when you rub it between your fingers—this stuff is exceptionally thin and airy. That thinness helps it be as permeable to air as possible. So, when it’s worn alone, it keeps you very cool.
Wanting to take a decidedly ultralight approach to this particular backpacking trip, I opted for my Hyperlite Mountain Gear pack. Made from non-woven Dyneema, it’s exceptionally light, but it forgoes any sort of Osprey-style mesh suspension in pursuit of minimalism. That means the non-breathable fabric is pressed right up against your back, which can drench you in sweat on hot days.
I wore a similar pack, and a 125-weight, all-merino shirt, when I hiked Mt. Washington a few months back. That day saw temps reach 85 degrees, and my back was totally soaked by the time I reached the summit. So much so that for a time I was convinced my hydration bladder was leaking. In the Enchantments, temperatures were about the same, but in the Voormi T, my back remained mostly dry. Even while scaling Aasgard Pass. I’m convinced the lighter, more breathable fabric, combined with the wicking synthetic fibers, really does work to keep you a little cooler and drier in hot, high-output conditions.
That night, we camped near the top of the pass, at about 7,600 feet. We were surrounded by frozen lakes and snow fields, and temperatures dropped well below freezing. By that time, the shirt had dried totally, and I layered an ultralight down jacket and hardshell over it. I was warm. That’s the benefit of merino wool; it makes an excellent base layer across a very wide variety of temperatures. I’m not saying I was as warm as I would have been in something heavier, just that the same shirt that kept me cool while working hard during a hot day also worked to keep me warm enough on a cold night.
Two days of challenging hiking, and cold nights later, I was still comfortable, and Voormi’s ultralight shirt showed no signs of fraying or other wear. And like any good merino, it didn’t smell like an old shoe after hours of wear.
The final test for any merino garment is how well it holds up in the wash. All merino makers suggest you wash such garments in cold water, then air dry them. But I’m doing my best to keep the bachelor stereotype alive, and am exceptionally lazy about doing my washing. That means a) I wear a lot of merino because I don’t have to wash it much, and b) I throw everything together in the same warm wash cycle and same medium heat dryer. Three washes in, this T is holding up just fine, exhibiting no holes or worn areas. Other 125 to 150-weight items have begun to rip in that time under similar abuse.
Voormi's final claim for Dual Surface UL is that it’ll protect you from sunburn. That’s true of all merino-based products and we found no difference here. It’s worth noting though that because of how light the material is, Voormi is selling a hoodie made from it, designed for hot weather. The hood is there not to provide insulation, but to protect you from the sun. On the water or on a slopes, that should keep you cooler than most hats, while providing additional protection for your neck and ears.
Is this new product range for you? I prefer wearing Patagonia Merino Air base layers for active pursuits in sub-freezing weather, and find the style of Trew’s T-shirts to be far superior for wearing around the house. But, if you need one performance shirt that can work in moderate temperatures as well as it does heat, and which will resist stink for days, then this probably is the best option yet. It truly is a one-shirt solution for summer playtime outdoors.