Personal Biographical Information:
Name: André Corterier
Gender: M
Age: 34
Height: 1.85 m (6 ft 1 in)
Weight: 80 kg (175 lb)
Chest: 100 cm (39.5 in)
Waist: 84 cm (33 in)
Shoulder Girth: 125 cm (49 in)
Email: andreDOTcorterierATfreenetDOTde
Home: Bonn, Germany

Backpacking Background:
I have started out with backpacking slowly – single-day 24 km (15 mi) jaunts by myself or even shorter hikes in the company of my little daughter. I am getting started on longer hikes, as a lightweight packer and hammock-camper. I’ve begun upgrading my old gear and am now shooting for a dry FSO weight (everything carried From the Skin Out except food, fuel and water) of about 10 kg (22 lb) for three-season camping. I am getting there.

Year of manufacture: 2006
Manufacturer: Mont Bell Co. Ltd. (Montbell)
URL: http://www.montbell.com
MSRP: 255 USD

Listed Weight: 1 lb 6 oz/22 oz (624 g)
Measured Weight: 606 g (21.4 oz) for the bag, 24 g (0.8 oz) for the stuff sack, 630 g (22.2 oz) total
Listed Dimensions (Stuffed): 10.4 in by 5.3 in (26.5 cm by 13.5 cm)
Measured Dimensions (Stuffed): 11 in by 5.3 in (28 cm by 13.5 cm)

Introduction:
This is a light, elastic, mummy-shaped down bag with a hood. The manufacturer claims that I should be comfortable in it wearing nothing but a base layer in temperatures down to 32 F (0 C). It has a zipper running down almost the entire side of it. For a more detailed description of the bag, see my Initial Report.

Field Experience:
I have spent a dozen nights in this bag, in shelters (including houses), under a tent-shaped tarp and the open sky. Elevations ranged from just above 0 to just shy of 500 m (0 to 1600 ft), humidity was generally low except for one condensation "stress test" on a humid night next to a river bank. Temperatures ranged from about 8 C to over 20 C (45 F to 70 F). The bag was usually used atop an Exped Down Air Mat, sometimes on a mattress, but not yet in a hammock.

Comfort:
The bag has been very comfortable to sleep in. The material is soft on the skin and has never been clammy, not even when used in humidity which must have approached 100 %. There is a noticeable buildup of static electricity when the bag's material rubs against itself - as is unavoidably the case when unpacking it. While this generates a bit of a light show when I unpack the bag at night, the electricity thus generated has not generated painful sparks or anything of the kind, nor has it in any other way been detrimental to my sleep.

Probably the most wonderful feature of the bag as far as comfort is concerned is the elasticity of the bag. I don't toss and turn much, but I usually do feel somewhat constrained in my usual mummy bag. This has not been the case with the MontBell Alpine DownHugger. It hugs without restraining. Difficult enough for people to do - this bag does it just right. Coupled with the comfort and warmth of the Down Air Mat I used, this bag has led to one of my most comfortable nights spent outside to date, in which I fell asleep at midnight, opened one eye at dawn, turned around to go to sleep again until woken at 6 a.m.

One minor issue I have had with the bag is that it is extremely slippery. The first night I wanted to use it outdoors, I had dumped my mat on a slight incline which I had considered too insignificant to interfere with sleep. However, as I moved into my bag, I slid downhill with the bag by a few cm (few/2.5 in) so that my feet were off the mat. Trying to wiggle my way back up were counterproductive, as any movement I made caused me to slip further downhill. I soon realized that sleeping on my mat at an incline was going to be impossible in this bag. So I turned the mat perpendicular to the slope, created a little flat depression just large enough for my mat by digging a teeny little trench and sculpting the excavated material and then slept blissfully. The slipperiness has also been noted when I used the bag, opened up and spread out on top of me for ventilation, on my bed at home. Once enough of it hung over the side of the bed, the entire bag slipped off me. This has not been an issue when sleeping closer to the ground and I trust it won't be an issue in my hammock, where I create the lowest spot inside the hammock through my body weight. I will find out whether this slipperiness inhibits my ability to get onto my pad in my hammock (and to stay on top of it through the night) and will report on this in the Long Term Report.

Temperature Range:
As mentioned above, the lowest temperature at which I have used the bag was about 8 C / 46 F (at some point during the night). When I zipped up my bag, it was about 12 C / 54 F. I was wearing nothing except for a long pair of nylon wind pants (in case I needed to go through a potty break in the brush surrounding us). I zipped up the bag, left the hood of the bag wide open and went to sleep. I was quite exhausted, but adequately fed at the time and - as far as I can tell - sleep neither particularly warm nor cold. When I sort of awoke at a time approaching dawn with the temperature having dipped, I was cool in my bag though not yet uncomfortably so. I snugged the hood a little closer and went back to sleep. I awoke the next morning well rested though confronted with a hiking companion who had been quite cold all through the night in a down bag of similar weight though different manufacture. Being woken to that description of the night somehow made me feel smugly (and snugly) superior, as I was still lying in my warm bag.

I have begun venting the bag by partially unzipping it from temperatures of about 15 C or a little above that (60 F). In the warmest nights to date (over 20 C / 70 F) I have used the bag as a quilt, entirely unzipped and with my feet in the "Bottom Adjuster". This has allowed me to move around a little at night without the bag slipping off me entirely, as it was fixed to my feet. This did become too warm occasionally, but venting my feet by taking them out of the Bottom Adjuster was easily accomplished.

Moisture Management:
I had undertaken a bead test with the bag, but forgot to report on it in my Initial Report. A cupful of water poured into a little depression formed of the bag's surface simply sat there for a minute. I was able to shake it off and noticed no darkening of the bag's surface which would have been indicative of the bag taking up moisture. I was quite pleased with this. I intend to repeat this test towards the end of the Long Term testing period.

My daughter unintentionally also performed a spill test on the bag. The exact path which the liquid took past the bag is not known to me as I came upon the scene later, but it clearly flowed past the bag, coming in contact with it but not penetrating it. I was happy about that as well.

The bag's DWR encountered its limit in a condensation stress test I performed inside the confines of a shaped tarp which acted much like a tent under the circumstances. I had set up camp on the banks of a creek in a very humid night. The next morning, both inside and outside of the tarp's surface were drenched with moisture. At the top and the bottom of the bag, where I assumed it came into contact with the tarp during the night, dark spots showed that some of the moisture accumulated there had made its way into the down. I packed it up without drying it first, took it home and put it on my gram scale to show that it had gained 26 g (0.9 oz) of weight. Spreading it out in the sun on the balcony took care of this. So while this DWR is not infallible (no DWR treatment encountered by this tester to date has been), it seems to be doing its job well. The bag did not appear to have lost any of its "fluff" due to moisture (which I take to mean that no clumping of the down had resulted).

Packing:
The bag has been easy to pack. At the listed dimensions for the bag inside its stuff sack, it was easy to find a spot in my bag. I have used the Bottom Adjuster for packing the bag into its own foot end several times, which works well, particularly if space inside my pack isn't at a premium. At first I would still pack it into a garbage bag - it was later that I realized that the garbage bag actually weighed more than the stuff sack which came with the bag. Still, the garbage bag is a multi-use item (impromptu wind shirt, water container, tinder - even as a garbage bag) so I may still use it that way. I do note that the stuff sack delivered with this bag is *very* light.

Durability:
There have been no durability issues so far. At three separate times I have seen a single down feather partially sticking out through the fabric of the bag. I have left them where I saw them. I believe that they went away of their own accord - whether back into the bag or entirely out of it I cannot tell. It might be that I've seen the same one twice (though not, I'm pretty sure, three times). I have not noticed any down *loss* so far.

Cleaning the bag up requires a moist towel or something else - just shaking it out as I'm used to with my other bag doesn't work so well. The reason is the static electricity which has built up in the bag. Dry leaves and similar things which came into the bag with me clung to the bag's surface even against vigorous shaking (I guess I was building up more static by vigorously shaking the bag, thus countervailing my own efforts). The bag hasn't picked up dirt stains or anything of the sort though it's been in contact with the ground often enough, so I remain very happy with it.

I have found the fluffiness of the bag well preserved. I have - accidentally - kept it packed inside its stuff sack (though not at extreme compression) for over two weeks in a row (in which I had meant to take it out testing, but was stuck at the place we stayed for family reasons). When I took it out thereafter, it still required no more than some rigorous fluffing up to regain its loft. I am happy about that (yet will endeavour to store it uncompressed in the future).

Specific Questions and Their Answers So Far:

Warmth: Obviously – will I be warm enough in just a base layer down to freezing? Will I overheat in summer? How easy is venting with the zipper when it's zipped up, what is the spectrum of adequate warmth when I use the bag as a quilt? (I'll carry a little lightweight thermometer around to enable accurate reporting.) It's been quite warm down to 8 C / 45 F with the hood only partially drawn. I've been able to make use of it up to just over 20 C / 70 F.

Comfort: Will it fit me? (My shoulder girth is on the low side of the manufacturer's given range, as is my height – for the "Long" bag.) Yes, it does. Will I notice anything different on my skin regarding the "calendared" thread? No. Will the inner lining feel good? It's okay. Will it be clammy if I'm warm (or, worse, even if I'm cold)? No. Can I get into and out of the bag without problems, or is finagling the zipper open an exercise unsuitable for a sleepy person with a full bladder? I have not encountered any problems. Particularly, the bag has kept me warm enough that midnight potty breaks weren't necessary. Will the single draft tube prevent drafts? It hasn't been breezy enough to really test this feature, but I have felt no drafts inside the bag so far. How well does the hood fit, and how easy is it to adjust in the dark? Very (in both instances). Will the "Gathered Quilt" system of elastics sewn into the baffles make the bag feel roomier than its cut would imply? Absolutely. It works like a charm. If due to the way I turn I stretch the bag in the horizontal, will this reduce the loft in that area, resulting in a cold spot? I have not noticed this.

Packability: Does the bag really compress down to 5 by 8 in (12.5 by 20 cm) with the help of the compression sack? Yes. If carried without the compression sack (wrapped in a garbage bag or just stuffed into the last baffle with the help of the "Bottom Adjuster"), how much volume does it require? Hard to say - it's about the size of a normal pumpkin, but of course it can be compressed further.

Loft: How much loft is there? Just over 5 cm / 2 in between my body and the outside when I draw the bag slightly out to allow measurement, thereby stretching it a little. I guess it has more effective loft where the "Gathered Quilt" system tucks it in. How quickly does it recover from being somewhat compressed or very heavily compressed? A bit of fluffing up seems to be all that is required. In various levels of humidity? Humidity has not affected the bag's fluffiness in any way so far.

Weight: Is the reported weight (1 lb 6 oz / 620 g for the Long version) accurate? Yes - and it includes the stuff sack. How much does the compression sack weigh? 24 g/0.8 oz.

Durability: I am aware that such a lightweight sleeping bag, especially one that has considerably more weight in the down filling than in the fabric (!), requires care and will treat is as such. Still, if the zipper snags or I fail to notice a branch where I unpack the bag – will the fabric used (reportedly stronger than some fabrics twice the weight) be up to what wear and tear is unavoidable over four months (and hopefully beyond)? No issues so far. Will the calendared thread employed in the construction manage to avoid down leakage altogether? Probably not *entirely* but very likely close enough not to make a difference. But the verdict is actually still out on this one.

Moisture Management: How much moisture does the bag take on (from the outside/from the inside)? The maximum total was shy of an ounce (28 g). How quickly does it dry? (A "felt" guess in the field, which I'll try to back up with measured weight from my gram scale when testing close to home.) Two hours in the sun took care of it - it might have been dry sooner, but that's when I checked on it. Will I be able to observe the DWR in action (I guess I'll try a bead test)? Yes. It works. Will it still be as good when I write my Long Term Report?

Bottom Adjuster: An interesting gimmick. Will it help me adjust the bag to my personal length and warmth requirements? Length - no. I *just* require the long length according to the manufacturer's online sizing chart and cannot shorten the bag this way. I have not had the need to attempt to increase the bag's warmth with the Bottom Adjuster. Will it be a good stuff sack for the bag? Yes. Or could I do without the added complexity? I could, but I prefer it this way. Is it easy to adjust in my hammock in the middle of the night? Will it stay the way I set it if I toss and turn a little?

Vertical Box Construction: Keeping the down where it should retain most of the warmth is good, of course – but what if I sleep on my side? Will I have less down there then? What about my back (if I sleep on my side)? In my current bag, I can shift the down around on purpose – I guess I won't be able to do that here. Will that be good or bad? I have not had any issues in this regard at all. The bag has simply kept me warm all around. When I noticed heat loss, it was through the open hood and all I needed to do was close it.

Summary So Far:
I like this bag a *lot*. It's been the most comfortable bag I have slept in - ever. While really roomy bags have also managed not to constrict me, they would create cold pockets which I would feel when moving around. This bag kept me warm *and* did not confine me, and I love it for it. It has held up to as much of the claimed temperature range as I was able to test so far and it appears as though I wouldn't ever need a different bag to hike year-round in Midwestern Germany. It's not a summer bag, though - should I ever be on a multi-week summer trip, I might consider buying a different bag for the occasion (and a lighter one of this series would definitely be at the top of my shortlist of candidates).

Read more reviews of MontBell gear
Read more gear reviews by Andre Corterier

Field Report

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