Sierra Designs Zissou 15Sleeping Bag

Sleeping Bag
Sierra Designs Zissou 15
$260 regular, $280 long, 2 lb, 9 oz. (reg)
Sizes: regular and long
sierradesigns.com

For years, I’ve rarely used a synthetic sleeping bag because they’re so much heavier and bulkier than down bags, and I’m not often out on the sort of extended, really wet trips where a down bag can get damp enough to lose its loft and warmth. But the advent of hydrophobic down could be a game changer nonetheless, and the Zissou 15 is among the first sleeping bags on the market to use down feathers that resist saturation.

In short, Sierra Designs’ proprietary DriDown is chemically coated hydrophobic down that, according to Sierra Designs, repels moisture better and dries faster than untreated down, and retains loft and its ability to keep you warm when wet. (The other hydrophobic form of down, DownTek, is used in bags and down jackets from Big Agnes, Brooks-Range, EMS, L.L. Bean, Mountain Hardwear, Nemo, Mountain Designs, Reecho, Sea to Summit and Salewa.) My colleagues at Backpacker Magazine have found no discernible performance different in DriDown’s and DownTek’s ability to retain loft and warmth when wet, and reported this bag remaining fat and warm in very wet conditions that flattened traditional down bags.

On nights around freezing, from Idaho’s Sawtooths and City of Rocks to Oregon’s Eagle Cap Wilderness (where we had one night of cold, hard rain and high humidity that did not appear to affect the bag at all), I found the mummy-style Zissou 15 warm enough without even having to completely close up the bag (as did my wife, who sleeps cold and typically needs a bag rated at least 20 degrees lower than the coldest temperatures she expects to encounter). I also like the bag’s comfortably spacious fit from the hood and shoulders to the foot box—it doesn’t feel like a straitjacket, as do some bags—without being too cavernous to heat up efficiently. On the downside, the 600-fill down is heavier and bulkier than higher-quality down feathers (this bag packs to 8 by 16 inches in its non-compression stuff sack).

For more reviews of my favorite sleeping bags, type the words “sleeping bags” into the Search box at left. See also my Pro Tips articles “How to Choose a Sleeping Bag” and “Staying Warm in a Sleeping Bag.”

NOTE: I’ve been testing gear for Backpacker Magazine for 20 years. At The Big Outside, I review only what I consider the best outdoor gear and apparel. See all of my reviews by clicking on the Gear Reviews category at left or in the main menu. See more reviews of backpacking gear I like by clicking on the “backpacking gear reviews” tag in the tag cloud in the left sidebar.

—Michael Lanza