The Brooks Range Drift -10 won our 2017 Editors' Choice award, not because it's the lightest bag, or the most comfortable bag, or even the warmest, but because it scores high metrics in all of these attributes. This bag uses ultralight and durable weather resistant shell fabric, allowing for a roomy cut and loads of down, while still keeping the entire weight of the bag just over 3 lbs. In sleeping bag design, it's all about the warmth-to-weight ratio, and the Drift kills it.
Brooks-Range Drift -10 Review
Cons: Draft tube can get stuck in the zipper
Our Analysis and Test Results
This is the best all-rounder for when it's all-around cold out. The Drift is light enough for those on the move, but spacious enough to keep extra water and clothing warm inside the bag with you when you need to wait out the weather. If you're looking to go even warmer, have a look at The North Face Inferno -20, and if weight savings is your priority, check out the Western Mountaineering Antelope MF or the Mountain Hardwear Torch 3.
Scoring a 9 out of 10, the warming powers of the Drift are surpassed only by the heavyweight Marmot Col -20 and The North Face Inferno -20. Vertical baffles house 36oz of 850 fill-power goose down, keeping the insulation evenly in place over the whole bag, eliminating cold spots. Like the Big Agnes Storm King 0, the Drift uses the Insotect Flow system to keep the down from shifting around. Insotech incorporates tiny nets they call "flow gates" to stop the down from shifting up and down the bag while allowing air (heated by your body and insulated by the down) to flow throughout the length of the bag.
After laying in the bag and concentrating exceptionally hard for hours on the movement of hot air, our testers found themselves unable to distinguish if they were warm because of special air flow or just because they were inside a well-built sleeping bag stuffed with loads of down. Insotect claims their design reduces material requirements compared with traditional baffle systems, and that's a claim we can get behind simply by looking at the low material weights of the Drift. The draft collar is simple but effective, utilizing one cinch cord for the collar and the hood. Finally, a thick, fluffy, full-length draft tube guards the zipper and seals in the heat.
At 3lbs 5.4oz, this award winner scores a middle-of-the-road 6 in the weight metric. It's just over a pound heavier than the ultralight Western Mountaineering Versalite, and 7.8oz heavier than the efficiently sized Feathered Friends Snowbunting. The trade-off for the weight is a bag that is way warmer than the Versalite and much more comfortable than the Snowbunting.
The Drift's weight it is most appreciated when you consider the weight of the materials used compared to the insulation weight. The materials (shell fabric, stitching) make up about 32% of the Drift's total weight, versus 40% in the Versalite, and 44% in the Snowbunting, despite the fact that the Drift has a wider cut than either bag. Awesome! If weight savings is your main priority, check out the Western Mountaineering Versalite or the REI Co-Op Magma 10.
Our testers loved the wide cut and comfy hood of Drift. We were most impressed by the fact that the bag has so much room inside and still insulates well, which we attribute to the vertical baffle design. The extra room allows for extra layers, water bottles, boots, batteries, headlamps, and whatever else you don't want frozen solid in the morning. Scoring a near perfect 9 out of 10, this bag provides.
In warmer conditions, it makes for plenty of room to move around or comfortably sleep on your side. The only bag we find more comfortable is the Nemo Sonic which won our Top Pick for Comfort, but isn't as warm or weather resistant as the Drift.
There is over 2lbs of down in the Drift, and it took our testers a while to cram it into its included stuff sack. Using our compression sack we were able to stuff it to an even smaller size. Our lead tester prefers to put the bag in the bottom of his pack and let the bag fill up extra space. This also saves time in the morning as it is much faster than wrestling a huge fully lofted bag into a tiny sack.
The Drift packs down smaller than The North Face Inferno, the Marmot Col, the Kelty Cosmic Down, and the Big Agnes Storm King and takes home an 8 out of 10, as seen above. It is not as compact as the Western Mountaineering Antelope, the Mountain Hardwear Torch 3 and the Feathered Friends Snowbunting.
The Drift is simple and stripped down, dedicating most of its weight to insulation and a wide cut; basically, it has everything we like and no extra fluff. The "halo" draft collar isn't large, especially when compared to the collar on the Western Mountaineering Antelope, but it's stuffed with down and fits snugly around the neck (when cinched tight with its tiny pull cord that also tightens the brim of the hood).
A handy, smartphone-sized stash pocket with a small Velcro closure is located over the left side of the chest; it holds a headlamp or batteries for easy nighttime access. Alas, the Drift has one Achilles heel: the zipper. The puffy draft tube constantly gets snagged in the zipper. This drove our testers crazy, especially since they loved every other aspect of this bag.
After several nights of use, we discovered a solution for the zipper issue. As long as we were mindful and held the draft tube away from the zipper (with one hand while working the zipper pull with the other), the zipper functioned as intended. We still found ourselves wishing it was like the easy-gliding snag-free zipper on the Western Mountaineering Antelope. The Drift comes with a super light, paper-thin stuff sack and a large storage sack.
This bag was only outperformed in the weather resistance metric by the impenetrable but heavy Marmot Col. The Drift boasts three tiers of defense against the harsh winter elements. First, is the DWR treated 15 denier nylon shell fabric. The shell feels tough for being so light and it repelled water easily in our light rain testing. In our submersion test, where we hold the sleeping bag underwater and try our best to squeeze the air out, allowing water to seep in through the stitching and the shell fabric, the bag absorbed a tiny, marginal amount of water and re-lofted quickly.
These tests are well beyond the frozen precip conditions the Drift is designed to combat in the wild. The down itself is treated with a hydrophobic chemical called Downtek, which claims to maintain loft and increase drying time when the down gets wet. The shell performs so well that we weren't able to objectively test this feature. Finally, the full-length lofty draft tube made any cold moisture on the zipper side of the bag undetectable to our testers.
The Drift -10 deftly walks the line between being comfortable enough to spend weeks in at base camp, and being lightweight and weatherproof enough for alpine bivies. We recommend this bag for all types of winter camping, be it ski touring, alpine climbing, or just sleeping in the parking lot at the local ice crag.
At $750, the Drift -10 is the most expensive bag in its category…but it's also the best! High-quality ultralight materials aren't cheap, and Brooks-Range has incorporated them into an excellent design that maximizes the warmth-to-weight ratio. If weight is a concern for your winter trips, the Drift is worth every penny.
This Editors' Choice Award Winner has it all. Comfort, warmth, and excellent packability. Its unparalleled warmth-to-weight ratio sets it above the other high quality down bags in this review, and the wide cut made it an instant favorite among our testers. If you're concerned about the price, check out the Feathered Friends Snowbunting, a very warm, lighter weight alternative with an equally weather-resistant shell that trades in comfort for thermal efficiency, for $170 less than the Drift.
— Matt Bento