Most days I love breathable synthetic midlayers. One of the most popular apparel trends in recent years, the midlayer is intended to work as either insulation beneath a shell, or as a stand-alone outer layer during activities (like skinning) when a single base layer just isn’t enough. Midlayers vent on the bootpack, keep me warm on the lift, and look pro in the tram. But sometimes these wonder jackets fall flat. When I'm huffing up a long, too-cold-for-just-a-baselayer pitch they get overwhelmed with sweat and eventually turn cold.
That's fine while climbing an inbounds ridge where a warm lodge is just a ski away. But during longer backcountry missions, I've been leaving my synthetic midlayer behind and opting for Voormi's wool Drift Jacket instead.
To be clear, the Drift also gets soggy on these long, cold climbs, but over several years of testing I've found that the wool in this midlayer is significantly warmer when soaked through compared to its synthetic counterparts. I don't cringe when the wind hits my back during lunch and my core temp doesn't fall as I stand on a ridge and dig through my bag in search of a shell.
The reason? Wool is not as good as synthetics at moving moisture off your body so it can evaporate. But wool can absorb up to a third of its weight in moisture without feeling wet or cold. That means that when you're really working hard and sweating a lot, the Drift has a clear advantage.
I could wear a wool sweater but choose the Drift instead because it has some smart features that make it significantly better than something you'd buy from the Gap. Most importantly, Voormi found a way to reinforce the jacket's 21.5-micron wool fibers with separate, outer-facing nylon fibers. This combination makes the jacket more durable so it will put up tree branches, ski edges, and hours of rubbing from your backpack straps. The fiber combination also creates a tight knit that helps the jacket cut the wind and allows Voormi to apply a DWR coating that protects against a light snow or rain.
The Drift is slightly bulkier and heavier than a synthetic jacket of the same weight and it can smell like wet dog when soaked. At $250, it's also on the upper end of the price range for this kind of layer. But in my mind, those are minor annoyances compared to the overall technical advantages and warmth you get from the wool build.