Sierra Designs Zissou 6 DriDown Sleeping Bag

Matt Zia reviews the Sierra Designs Zissou 6 Sleeping Bag, Blister Gear Review.
Sierra Designs Zissou 6

Sierra Designs Zissou 6 DriDown Sleeping Bag

Size/Length Tested: Regular

Reviewer Info:
5’11”, 165 lbs.

Temperature Rating: 6° F

EN Comfort Rating: 19­° F

Shell Material: 30D Polyester Ripstop

Liner Material: 30D Polyester Taffetta

Insulation: 700 Fill Duck DriDown


  • Length: 78 inches
  • Shoulder Girth: 62 inches
  • Hip Girth: 58 inches
  • Foot Girth: 40 inches

Fill Weight: 30.5 oz

Trail Weight: 3 lb, 1 oz

MSRP: $340

Days tested: 20+

Locations Tested: Joshua Tree National Park, California; Red Rock Canyon National Conservation Area, Nevada; Indian Creek, Utah, Indian Peaks, Colorado.

While my romantic belief that I spend as many nights under the stars in a sleeping bag as I do in a bed isn’t quite accurate, I’ve still spent a significant portion of my life in a sleeping bag. And from backpacking in New Hampshire to mountaineering in New Zealand, a good amount of that time in a bag has been in damp, humid conditions.

When it comes to sleeping bags, I greatly prefer down to synthetic insulation. Pound for pound, down offers more insulation, compresses smaller, and is generally more comfortable to sleep in than synthetic insulation. But down is virtually useless when wet, as it losses its loft. Synthetic insulation, in comparison, still holds most of its loft when wet, continuing to insulate, even in wet conditions.

(For a more in-depth look at the differences between down and synthetic fill, see the “Sleeping Bags 101” section in Eric Melson’s review of the Kelty Ignite 0.)

DriDown hydrophobic down insulation and its competitor, DownTek, have changed the insulation game significantly. DriDown is down that has been treated with a hydrophobic polymer. And since each feather has its own coating, the entire sleeping bag is hydrophobic, not just its shell. The Zissou 6, filled with DriDown, is meant to combine the comfort and packability of down, with the wicking & wet-conditions performance of synthetic insulation. Sierra Designs claims that the DriDown coating results in sleeping bags that stay drier ten times longer, retain 170% more loft, and dry 33% faster than similar untreated down bags.

I was eager to test these claims in the field, and see how much better the Zissou 6 handles moist, damp conditions compared to regular down bags and synthetic bags.

Sizing & Fit

At 5’11”, 165 pounds, I’m on the slimmer end of the spectrum. For pants, I typically wear a 30×32, and am almost always a size Medium in upper body layers.

Sierra Designs says the Zissou 6 in the “regular” length should fit a user up to 6’ tall, which seems accurate—I tested the regular length of the Zissou 6, and it just barely fits me, but it is comfortable.

Sierra Designs markets the Zissou 6 as a mummy bag, but it seems a little wider through the torso section, and its footbox is a little roomier than other mummy bags I’ve used, like the Mountain Hardwear Spectre. This gives you a little more space to dry clothes in the bag, more room to sit cross legged, and, of course, it makes sleeping much more comfortable. However, the Zissou 6’s slightly roomier width is somewhat detrimental it thermal efficiency, which I’ll talk more about below.

Features & Design

The Zissou 6’s zipper has two zipper cars on it, and although the zipper does not run all the way to the foot of the bag, I still found that it vented very well around my feet with some of the zipper open at the end of the bag. The zipper also features an insulated draft tube that does an excellent job of keeping cold air from leaking in when the bag is zipped up.

The Zissou 6 also has a number of smaller features that are worth mentioning. The bag has four tie-down loops, two on each side, that can be used in conjunction with some narrow cord to keep a sleeping pad from sliding out from underneath the bag.

My favorite aspect of the Zissou 6, though, is the color of its lining. If you often keep a couple loose pieces of clothing in your bag with with you at night (to dry them, or just to have on you when you make up in the morning), I think you’ll appreciate it too. Where many sleeping bags have black lining, the inside of the Zissou is lime green. I’ve spent too much time feeling around the inside of a black sleeping bag on cold mornings trying to find a sock, but with the Zissou’s green interior, it’s a lot easier to spot things down inside the bag.

The Zissou’s headbox, the “hooded” portion of the bag that surrounds your head, is significantly wider than that of other bags, including my Mountain Hardwear Spectre. As a result, it was difficult for me to gather the material of the bag around my head enough to achieve a good, snug fit around my face. This wasn’t an issue on warmer nights, but on cold nights I had to pack the sides of the hood with a puffy to reduce the dead-air space around my head.

Matt Zia reviews the Sierra Designs Zissou 6 Sleeping Bag, Blister Gear Review.
Headbox of the Sierra Designs Zissou 6

Because Zissou 6’s headbox / hood is so large, the opening at the shoulders is also quite big. This usually isn’t an issue if a sleeping bag has a substantial enough draft collar (a tube of material that rests at your shoulders, at the opening of the bag, that helps keep warm air inside). However, although the Zissou has a draft collar of sorts, it’s only a small flap of material that runs along the front of the bag’s opening, and lacks a drawstring to cinch it snug around your shoulders / neck. On cold nights, I could feel warm air escaping around my neck, where a thicker, more substantial draft collar would probably have kept it in. I don’t think this is necessarily a deal breaker, but I think it does make the bag less suitable for those looking to use it quite often in very cold, extreme conditions, where a very snug mummy bag will trap heat more effectively.

The Zissou comes with a 16’’ x 9’’ stuff sack for packing, but has no compression straps, so it’s pretty bulky. With significant effort I found I could just barely fit the Zissou into a 10L stuff sack, but a 15L is much easier to pack the bag into, and is still quite a bit smaller than the included stuff sack.

It’s also worth mentioning that, immediately out of the box, I noticed some pretty significant clumping of the Zissou 6’s down fill and a few dead spots, but those disappeared after I stuffed and unstuffed the bag a few times.

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