Cocoon Merino Wool Mummy Liner

Cocoon Merino Wool Mummy Liner Review

in Gear by

I’ve built and slept in snow caves before. Not frequently. But I’ve done it enough to feel like my sleeping bag and I can handle the cold. So I’d never put much thought into buying a sleeping bag liner. If I could handle a night in a snow cave without extra lining, why would I need one at all? The Cocoon Merino Wool Mummy Liner has changed my mind. And not just because I first tested it on a particularly cold January night.

Cocoon Merino Wool Mummy Liner

The first night I used my Cocoon Merino Wool Mummy Liner, the nighttime low was 18°. We were camped near a lake, and the wind was whipping off the water toward us. I can’t say I was toasty warm inside the liner that was in my bag that was in my tent. I can say I was glad I had that extra 12.6° F.

Now that it’s part of my camping gear, the Cocoon Merino Wool Mummy Liner is like a favorite fleece pullover. Even if the temperatures are going to be tolerable, slipping inside that liner at the end of a hike is even more comfortable than sitting around a campfire.

But the real reason I’ve converted to the Cocoon Mummy liner comes anecdotally from one of my co-workers. As a Scout Master who spends even more time on the trail than I do, he was tired of having to buy a new sleeping bag every few years. But since he began using liners, he’s seen the life of his bag extended. According to him, a hundred-dollar liner is a better deal than a three hundred dollar bag every couple of years. And he’s currently using the Cocoon Merino Wool Mummy liner, too.

Good to know it’ll be more than a few years before I have to buy a new sleeping bag.

Cocoon Merino Wool Mummy Liner


  • An extra 12.6° Fahrenheit. That’s the added temperature rating it claims to give your sleeping bag. (That’s +7.0° for you Celsius-types.) That’s a lot of extra warmth for something that doesn’t add much weight to your pack.
  • Very comfortable without any constriction. Very soft and stretchy.
  • Extremely lightweight.
  • Avoids odor and and is germ-free. (I’m taking Cocoon at their word on this. I haven’t had it long enough to verify its odor-avoidance qualities.)
  • Theoretically, it extends the life of your sleeping bag.


  • Price. At $99.95, it might be a shock that something so lightweight and flimsy-feeling would cost so much. Some might be tempted to rationalize putting that extra hundred towards the price of a warmer bag.
  • Difficult to buy direct from the manufacturer. At the time of writing, the US website is under construction.





Manufacturer: Cocoon
MSRP: $99.95
Listed Weight: 17.5 oz. (495 g)
Materials: 100% wool.
Colors Available: black


As a kid, Greg hated backpacking. Hated tents. Hated sleeping bags. Hated cooking food around a campfire. And then, something clicked. A native Utahn, he began taking advantage of the state’s canyons and national parks. Working at the Grand Canyon during college solidified his need for a decent compass and water purifier. Attending graduate school in Virginia let him section hike the Appalachian Trail between semesters. He has lived and hiked in Chicago (more stair climbing than hiking), and Geneva, Switzerland. He currently lives in Dallas, Texas where he is a writer and brand creative for The Richards Group, the country’s largest independent advertising agency. He and his wife Suzy have four children, and if you visit their home, that’s exactly what it sounds like.

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