Montbell Alpine Thermo Bottle | Review - Outdoors Magic

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Montbell Alpine Thermo Bottle | Review

This sleek insulated flask is one of the best ones we’ve come across – no wonder it picked up a major industry award

Why We Chose The Montbell Alpine Thermo Bottle 0.9L: Sleek design, world-class temperature performance

It’s probably fair to say that Japanese brand Montbell aren’t particularly well known in the UK so you could call them a bit of a hidden gem to some extents. Mountaineering is primarily their focus, in fact it has been since 1975 when the brand was founded by Isamu Tatsuno, one of Japan’s most revered climbers and founder of the country’s first ever climbing school.

Take a look through Montbell’s website and you’ll see they make some very, very nice kit. There’s high spec sleeping bags, down jackets and backpacks, and there’s also some extremely well-made equipment, like this insulated flask called the Montbell Alpine Thermo Bottle 0.9L.

Who’s The Alpine Thermo Bottle For?

This isn’t any old flask. It’s designed for those heading high up in the most testing of conditions; the kinds of places where people want equipment that delivers but that also won’t weigh them down. It’ll serve particularly well, we reckon, for those day-long mountain missions when you want the sustenance of a hot drink right through until the end of the day.

Materials and Design

At 390g this really is phenomenally light for an insulated flask. To give you some perspective, Sigg’s Hot & Cold 1.0L Flask weighs 728g, the Primus Trailbreak 1L weighs 740g and the 946ml Hydro Flask is 444g.

As is the case with most insulated flasks – the good ones anyway – the Alpine Thermo features an inner chamber that’s surrounded by a vacuum within two walls of stainless steel. Montbell have gone one step further than most of its competition by making this vacuum super thin, they’ve also lined the inner chamber with a copper plate so that it’ll reflect heat back.

“Montbell have gone one step further than most of its competition by making this vacuum super thin”

Then there’s the cap. Normally this is a bit of a flash point for heat loss but Montbell have got around this by injecting an insulating fill into its walls.

A three-part system is involved. You’ve got the main body of the flask, an inner sealed cap that you twist to pour and then a top outer cap that doubles as a cup. It’s easy to use with gloves, though we will say that you’ve got to be mindful that the sleek metal casing doesn’t cause it to slip out of your hands.

Like most insulated flasks, it’s not machine washable but it’s pretty simple to wash by hand – you can get most scouring brushes right down to the bottom.

Montbell were founded in 1975 by Isamu Tatsuno. Photo: Mike Brindley
The cap has had insulating fill injected into its walls. Photo: Mike Brindley
An industry award winner. Photo: Mike Brindley

Temperature Performance

As you’ll see on the product listing for this on Montbell’s website, this will be able to keep your drink hot or cold for as long as 24 hours. Say you start the day with a boiling hot drink of 90C, the next morning you should have something that’s above 50C – so that’s above lukewarm temperature. The opposite way around, if you started with a 4C drink, after 24 hours it shouldn’t have risen much higher than 15C. Of course, it does all depend on the frequency that you are opening this up to drink it.


This is an impressive bit of kit and it’s no surprise to us that it picked up an OutDoor Award when it was released back in 2016. From our experience with it, it’s not only lighter than most of its competitors but it’s also a more effective insulator. To top it all off, this thing is extremely durable – something you’ll be able to count on.

You’ll find this not only in the 0.9L capacity version pictured, but also in 0.35L and 0.5L. As is often the case with vacuum flasks, the smaller capacities have lower insulating performance.

Montbell Alpine Thermo Bottle 0.9L

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