Cocoon's Mountain Wanderer Sleeping Bag

Preface

The following assumes the use of a tent or hooped bivvy (hammock and or tarp / non-hooped bivvy users will need to decide whether such a system may benefit them). We currently use a hooped bivvy + tarp in cold conditions, a tarp + regular bivvy for everything else.

A great deal of testing in varied conditions has brought us to recommending this "modular system". However, more than perhaps any other item, sleeping bags and their worth appears a very personal matter. Everyone's metabolism is different, some sleep hot, some cold, some on their side, some on their back, some probably sleep upside down ... who knows.

All we can do here is recommend what works for us and in doing so provide some useful information to consider before spending what can be a considerable amount of money and often the largest budget item(s) in any pack.

We also assume some sensible sleepwear and this combination has been tested with the thermal underwear recommended in our "sleepwear section" (we do not assume the wearing of insulated jackets or over-trousers).

The combination of sleeping bags we recommend are intended to work together enabling their user to carry only what is likely to be necessary for each trip. This combination will work from the arid to the tropical and down into frostbite territory. It uses mainly (wet weather resistant) synthetic insulation (and if down is recommended, the down bag is always on the inside, except in conditions where warm dry weather is predictable and persistent).

This system will not be too relevant to those who venture out only when it's a nice day; but will likely be of interest to those who enjoy the challenge of enduring the unpleasant conditions that hostile environments visit upon them.

Test subject: Chest 42", Waist 33", Height: 5ft 8"
Test item: Size = M (185 cm)
Kit Tests: Spring, Summer, Winter
Disclaimer: None required (item not provided by manufacturer)

Datasheet

Manufacturer's Page

 

Scramble Review

Contents

• Introduction: Reasons To Look Beyond The Cloud
• Scramble's Recommended Sleeping Bag System
• Features & Materials: MW's Synthetic Minimalism
• Temperature Rating: Solo & Paired
• Sizing
• Any Negatives?
• Conclusion, Rating & Product Images
• Postscript

 

Introduction: Reasons To Look Beyond The Cloud

For a long time we'd recommended Alpkit's Cloud Cover as our choice for an ultralight hot weather sleeping bag and inner bag to pair with the two synthetic "outer" (and solo) bags in our recommended "modular system". However, Alpkit's inability to check the ravages of inflation which has seen, in the space of 10 years, the Cloud Cover go from £65 in 2016 to £160 (at the time or writing, an annual inflation rate compounding at close to 10%) has shifted the Cloud Cover from something you'd give a go to more of an investment that better not let you down. Don't get us wrong, it's a very useful item and although it will no longer be part of our core system recommendation (and has been archived) we're going to continue to recommend it, but only for those for whom weight is the primary concern. We've adjusted our rating for the Cloud Cover accordingly and have for a while been seeking out alternatives.

So What Are We Looking For?

As we mentioned, the purpose of "Sleeping Bag 1" is to work on its own in hot / warm conditions where one is confident that nighttime temperatures are not going to drop below +10°C.  This bag needs to be light and compact and pair well with the other two bags in the system, both of which accommodate inner / liner sleeping bags to extend their ratings into sub zero or extreme sub zero temperatures.  The best way to get this across is simply to start at the punchline and work our way back to explain why Cocoon's Mountain Wanderer fits in so well and in many ways is superior to Alpkit's Cloud Cover.
 

In Context: Scramble's Recommended Sleeping Bag System

Many military modular systems use 2 bags: a lighter "patrol" bag (down to 0°C) and a medium-weight cold weather bag (down to -15°C) which combine for extreme cold (down to -30°C, but a total weight of nearly 3kg). Scramble's recommended modular approach uses 3 bags, is lighter and more flexible (better in hotter, arid conditions, yet still good down to -25°C (via our core recommendation) or around -20°C (using the Cloud Cover), the extreme combination weighing a little over 2kg).

Measured weights (without stuff sacks, see our note below*). CL = Comfort Limit:

Scramble's Current (Core) Recommendation (for extreme cold with better all-round wet weather performance)

• Hot + Dry or Wet Weather (CL= +8.0°C): Cocoon Mountain Wanderer (M) = 558g (stuff sack +14g)
• Warm + Dry or Wet Weather (CL= +5.7°C): Carinthia G-90 (L) = 694g (stuff sack +64g)
• Spring, Autumn (CL= -5.0°C): Mountain Wander (M) + Carinthia G-90 (L) = 1,252g
• Winter (CL= -15.0°C): Carinthia Defence 4 (M) = 1,650g (stuff sack +209g, we use an Osprey UL Pack Liner, Small, 30 - 50L = 78g)
• Extreme Cold (CL= -25.0°C): Defence 4 (M) + Mountain Wander (M) = 2,208g (stuff sack = Osprey UL Pack Liner, Small, 30 - 50L = 78g)
   

Scramble's Archived Version (lighter but less flexible at the hot and very cold extremes)

• Hot + Dry Weather (CL= approx +10.0°C): Alpkit Cloud Cover = 438g (stuff sack +14g)
• Warm + Dry or Wet Weather (CL= +5.7°C): Carinthia G-90 (L) = 694g (stuff sack +64g)
• Spring, Autumn (CL= approx. -2.0°C): Cloud Cover + Carinthia G-90 (L) = 1,132g
• Winter (CL= -15.0°C): Carinthia Defence 4 (M) = 1,650g (stuff sack +209g, we use an Osprey UL Pack Liner, Small, 30 - 50L = 78g)
• Extreme Cold (CL= approx. -20.0°C): Defence 4 (M) + Cloud Cover = 2,088g (stuff sack = Osprey UL Pack Liner, Small, 30 - 50L = 78g)

The beauty of the Carinthia G-90 and Defence 4 is that both have sufficient room to accommodate the Mountain Wanderer without overly compressing it and reducing its thermal efficiency. In addition, warm air is trapped between the two bags providing a double glazing effect.

If I was just starting out and was looking into my first sleeping bag setup, where I might venture out in the winter but was not interested in battling extreme cold, I'd strongly consider a dual bag set-up with Carinthia's Defence 1 (D1) and Cocoon's Mountain Wanderer (MW). For around £200 (shopping around) you'd get a light summer bag (MW), a late spring and early autumn bag (D1) and when paired they'd safely get you down to -6°C (-8°C by the ratings). Discarding Carinthia's heavy stuff sack, you'd be carrying a little over 1.5kg. For an ambitious beginner or for that matter most people in the UK, that wouldn't be a bad option at all. 
 

The Mountain Wanderer Compared to Alpkit's Cloud Cover

As we go through this review we'll occasionally draw comparisons to Alpkit's Cloud Cover.  You'll notice Cocoon's sleeping bag wins on most counts, but it loses on an important one: weight. The weight difference (allowing for plus/minus production tolerances) is somewhere between 110g and 120g.  It's not massive but it's not negligible either and for that reason alone, we aren't going to abandon the (now archived) Cloud Cover completely. Instead, we recommend it only for those that want to reduce pack weight above all else. 
 

Features & Materials: Synthetic Minimalism

Cocoon's Mountain Wanderer is a very stripped-down, minimalist sleeping bag. It's only available with a left-side zip, it has a dual-cinch cord for pulling in the hood and sealing at the neck. Aside from an internal pocket, a dual (inner/outer) zip and some hanging loops, that's really all there is in terms of features.

Cocoon's Mountain Wanderer is not a complicated piece of kit.

Materials

Cocoon have used a 45 g/sm 40D ripstop nylon on the outer with minimal stitching over its top surface (similar to Caranthia's sleeping bags - another Austrian manufacturer) which helps retain warm air trapped in the bag's Ecopet Performance insulation. The inner nylon fabric is silky smooth. No issues to report in terms of comfort.

If there was a standard clipart image symbolising a sleeping bag, it would probably look like the Mountain Wanderer.

Features

The Mountain Wanderer uses a 2-way #5 left-side zipper which has anti-snag webbing stitched along its path. The bag can be unzipped from inside or from the outside.  All quite standard stuff. Cocoon have not tried to re-invent the sleeping bag. 

Cocoon's Mountain Wanderer, like most bags can be opening from the inside and the outside.

A dual-cinch cord adjusts the hood volume and seal at the neck. The stopper is solid and their choice of cord offers a good degree of friction preventing loosening.

The dual-cinch works well, but one wonders if Cocoon could have left out the inner pocket (it's something of a gesture).

There's a simple non-fastening (insecure) pocket (pictured above, right) to store a head-torch or whatever else you may need access to in the middle of the night. A velcro closure would have been nice (but such niceties add weight). Instead, it has a fold-over flap which, pressed against the body, should prevent items falling out. It's okay. Personally I store a head-torch in my chest pocket (if my top or gilet has one), as I never sleep on my front.

At the footbox are two hanging loops for drying out the bag if it gets wet in the field, or for drying it out prior to storing it away.
 

Temperature Rating: Solo & Paired

Solo

One of the major advantages of the Mountain Wanderer (MW) over the Cloud Cover is that Cocoon had their sleeping bag independently tested; it has an EN 13537 (European Standard) temperature rating.  So we don't need to make fuzzy guesses as to its warmth. At least for us, this is a big deal and we generally steer clear of manufacturers who aren't sufficiently confident of their product to have it chamber-tested so it can be rated and measured against its peers.

On top of the EN Comfort Limit (the relevant measure for men) +8°C rating of the Mountain Wanderer as a solo bag, Cocoon also state that their sleeping bag, when used as a liner bag, will add 12°C.

Paired (As A Liner)

Adding 12°C as a liner would mean, when paired with the Carinthia G-90, you'd achieve a Comfort Limit (CL) of -6.3°C. To be on the safe side, we've shaved a little off that and approximate to -5°C. 

We wanted to know if Cocoon also EN tested this metric. We'd heard from their UK distributor that they test their liner bags and so we contacted Cocoon and their reply was speedy and helpful.

To paraphrase, the Mountain Wanderer's 12°C added warmth as a liner is a "rather conservative estimate" based on the EN testing data from their range of liners. As an example, Cocoon's designer noted: "the tested added warmth of [Cocoon's] Thermolite Radiator liner is 9°C". The Mountain Wanderer will certainly be warmer than that. So, by adding 10°C, we've taken their conservative estimate and made it even more conservative. In our view, using a range of 10°C - 12°C added warmth should be fine. However, we'll stay safe and keep it concise and say one can expect to add at least +10°C by using the Mountain Wanderer as a liner bag.

One of the things we like about inserting the Mountain Wanderer into our modular system is that, from warm to extreme cold, each combination's drop in temperature rating is uniform (around 10°C). So there are no obvious gaps that may need to be bridged. If you think a CL of -5°C (with the G-90 + Mountain Wanderer) may be pushing your luck, you can switch to the Defence 4 which will buy you another 10°C of leeway. Likewise at -15°C, by adding the Mountain Wanderer to the Defence 4 you get another 10°C of coverage.

Sizing

Like many sleeping bags, the Mountain Wanderer (MW) comes in two sizes: Medium (185cm) which we'd recommend for anyone under 6ft and Large (200cm) which is suitable for those 6ft and over. Theoretically, someone who's 6ft should fit into the Medium, but it might be tight depending on their physique (for example if someone has broad shoulders they might want to consider sizing up if they're bang on 6ft tall).

For those over 6ft, Rab's Solar Eco 0 (Size L) maybe of interest. It weighs about the same as the MW Medium and has the same +8°C Comfort Limit (ignore Rab's own 5°C nonsense).  However, there are a number of things we didn't like about the Solar: a) it uses a much lighter polyester ripstop outer (so it's not going to be nearly as durable); b) their Stratus insulation is not the best in terms of compression / packability and c) it uses less insulation on its underside, which for a looser outer bag can make sense (as, in theory, the underside insulation gets compressed by the body), but for a potential liner, in practice this makes less sense. Sleepers move all over the place at night, especially side sleepers like me, and mummy / liner bags moves with them. So, less insulation on the underside can easily become less insulation on your exposed back. However, for tall, front and/or back sleepers, the Solar Eco 0 may be an alternative.
 

Any Negatives?

There are three minor negatives in our view. 

One is the internal pocket.  It's a minor niggle and we know everyone expects to have one, but for this kind of minimalist sleeping bag you wonder if they could get away without one. If Cocoon felt they absolutely need one, then at least give it a velcro seal. 

The other two negatives relate to weight and packability.  These are the two factors where Alpkit's Cloud Cover has the edge. However, we need to make something clear regarding the product photos of the Mountain Wanderer which comes with a stuff sack, not a compression sack (likewise the Cloud Cover).  Obviously, this keeps the overall product weight down but it also makes it look like the sleeping bag is more bulky when packed than it need be. We pack most of our sleeping bags into dry bags (large ones into small ultralight pack liners), sitting on them to release the air makes them (vacuum) pack down way smaller than they look in the product images below.  That said, the Cloud Cover, packed in the same way, packs down smaller than the Mountain Wanderer.

The Mountain Wander is between 110g and 120g heavier than the Cloud Cover.  For that weight premium you get:

• a sleeping bag (rather than a quilt),
• that has been independently rated,
• that seals with a zip rather than poppers,
• that has a hood,
• that can be cinched and sealed at the neck, and
• that is at least 2°C warmer (maybe more). 

In addition, there no doubt that Cocoon's Mountain Wanderer, when used as a liner, adds substantially more warmth than Alpkit's Cloud Cover (which due to its lack of a rating remains merely a guesstimate). Furthermore, when used alone, in hot and warm weather, the Wanderer's synthetic insulation means you don't need to worry nearly as much about reduced performance in wet conditions. So, for adding a little weight on your back, you get to take a little weight off your mind.

 

Conclusion & Rating

Cocoon's Mountain Wanderer (MW) is a stripped-down, straight-forward, near-minimalist synthetic sleeping bag which tapers in an unaggressive mummy fashion to a standard 50cm footbox (55cm size L).  No attempt has been made by Cocoon to re-imagine anything, rather they've concentrated on the basics and stuck to them. They've used a light yet durable ripstop nylon fabric with minimal top stitching to prevent heatloss. The Ecopet Performance insulation is made from recycled polyester and according to EN 13537 it does its job.

The Mountain Wanderer works fine as a solo summer bag (with a Comfort Limit of +8°C) where nighttime temperatures aren't expected to be drop below +10°C.  However, where it really shines is as a liner bag, providing at least +10°C (stated / proxy-rated +12°C) when paired with accommodating bags like those in Carinthia's Defence series and Carinthia's excellent G-90 (size L). 

Would we like it to be lighter?  Of course, we'd be happier if the Mountain Wanderer was in the 450g range (like the Cloud Cover) rather than ~550g.  But when we compare the two offerings, Alpkit's vs. Cocoon's, it's easy to see why, for our modular system, the Mountain Wanderer wins :

It's an EN-rated sleeping bag, not a quilt; it weighs about the same as Alpkit's down Pipedream 200 (which is 0.6°C warmer and costs more than twice as much); unlike the Cloud Cover it has a zip rather than poppers and has a hood and can be cinch-sealed at the neck; it functions better in wet conditions and is at least 2°C warmer. On top of all that, it costs less than 60% of the Cloud Cover's ever-inflating price (based on RRP).
 

Cocoon's Mountain Wanderer improves a modular system that we were already quite pleased with; extending its range down to -25°C (possibly -27°C) and creating a more uniform temperature ratings descent with each sleeping bag / combination.  We feel the 110g - 120g weight premium is well worth it, for those that don't agree, there's nothing wrong with the Cloud Cover (it has its advantages, afterall we recommended it for about eight years). However, as far as our core, three sleeping bag modular system goes, it's Austria with a clean sweep.  Cocoon's Mountain Wanderer is a great value sleeping bag and our top pick for "Sleeping Bag 1" (1 Season and 4 Season Inner).

 

Product Images

 

Rating (out of 10)

* The value score is derived from two factors:
1) Competitive Market Price (CMP). This represents our judgement of a competitive online price point if we were to stock the item. e.g. if we feel we would need to sell an item at 40% off (i.e. 60% of its full RRP) to be competitive, then our CMP score will be 6/10.
2) Customer Value Price (CVP). We then make an honest appraisal of the maximum price we would be willing to pay for the item (and we're mean). So if we'd pay 80% of its RRP our CVP score would be 8/10.
We then average the two scores to get our final value score, which in our example would be 7/10.

 

Postscript

Why not down all the way?

As an inner bag, down is superb. If you can guarantee arid conditions (deserts, Himalayas, arctic etc.) then down is the way to go, but for the UK and northern Europe, not so much and you literally have to factor in a daily thermal performance loss for down in wet conditions (regardless of hydrophobic patches to an insoluble problem).

Andy Kirkpatrick explains:

"There is nothing as great as a bone dry down sleeping bag. Unfortunately there is also nothing as grim as a wet one. Saturated down loses 90% of its insulation as the delicate structure of the clusters stick together and collapse. The down absorbs a lot of water and because it loses most of its thermal performance it must be dried via an outside heat source like the sun, a tumble dryer or a body. In many cases where there is moisture present, a down bag will lose performance each night it is used, as the down becomes slowly saturated. The rate at which this happens is dependent on the skill of the user and the conditions in which it is being used. This water contamination comes both from without and within the bag and learning to slow the speed of this performance drop is one of the skills needed to use a down bag effectively. Down just doesn’t work in high saturated environments and best suits cold and dry conditions, or the protected sanctuary of a dry space like a tent, hut or snow hole."

Our Winter Kit test in 2016 was particularly tricky and saw 4 days of permanent heavy rain, hail and sleet book-ended by 3 days of freezing cold (down to -8°C). Everything got wet (regardless of care and skill) and the Defence 4, being synthetic held up superbly, a down bag would have been a disaster and quite possibly dangerous.

* A note on stuff sacks and weight stats

We don't quote the weights including stuff sacks, mainly because we don't feel the manufacturer's choice of stuff sack design has a great deal to do with their sleeping bags (an example is Mountain Hardwear's Lamina bags which come with something more akin to a Tesco's 10 gram shopping bag, whereas Carinthia's come with military grade compression sacks; apples and oranges and all that. In addition we only use a stuff sack for the sub-zero bag, and for that we use an Osprey Ultralight Pack Liner (S, 30 - 50L) The G-90 can simply go in the base of ones pack (assuming it has a waterproof liner) as it fills the nooks and crannies well and gets compressed by all your other kit. The Cloud Cover comes with a superlight sack and likewise easily gets compressed when you cover it with the rest of your stuff. If it's used as an inner, then it can just go inside the G-90 or the Defence 4.

 

Last Updated: 14/01/26
Added to the Sizing section