Outdoor Research Interstellar Jacket
Lightweight and highly breathable waterproof protection.
The climbing market gets ever bigger but it is still small compared to cycling for example. Even just within mountain biking, there seems to be a continual push into ever greater specialisation of bike models. Within those increasingly specialist niches the bikes may be superb, but I wonder sometimes just how many people are in the market for steel-framed, single-speed, long-travel, 650b steed for bikepacking? Clearly there are enough cyclists worldwide that by being ‘niche’ enough you actually find a market rather than miss it, but is the same true with climbing?
The Arc’teryx Alpha Comp Hoody (can we just call it the ACH?) is, I feel, a niche product. Within that niche, it is fantastic - but with an RRP of £275 I can’t imagine it is likely to attract too much attention beyond people who know that this is their niche and want something just for it. This is not meant to be a criticism of Arc’teryx’s design of the ACH. Like so much Arc’teryx gear, the standards of design and construction of the ACH are superb.
All the things that Arc’teryx is famous for - micro taping, lamination, fantastic quality of the seam sewing - are there. The helmet compatible hood is great; it swallows even bigger helmet designs, still moves with your head when you turn and the zip comes up to protect your lower face but isn’t tight. You have two big hand warmer pockets that sit above the harness line. You can stuff gloves or even a map into them. There is one medium sized chest pocket that can take a phone or compact camera easily enough.
One new feature for me is the removable ‘harness hemlock’ inserts.
These are tube-shaped pieces of foam that slip into the hem, two on each side, making about 20 cms of a soft foam ridge that sits over your thighs. When wearing the ACH you don’t feel them at all but they stop the jacket from being pulled out of your harness even when doing the silliest of moves mixed climbing. They are a clever idea; the jacket is very stretchy particularly around the arms and shoulders anyway, but the hemlocks ensure the jacket stays in your harness.
What makes the jacket unusual (although not unique) is the mix of materials Arc’teryx use. The hood, shoulders, upper sides of the arms and a strip above the hem are “N40p 3L laminated Gore® Product Technology”. The torso and and underside of the arms is “Fortius 1.0 stretch woven fabric”, a rather thin and light softshell material. As far as I can work out the Gore material is basically what the rest of us call Gore-tex.
The Fortius 1.0 fabric is a very light and stretchy softshell material - it has some wind resistance but I wouldn’t call it windproof. Arc’teryx have obviously selected it to be very breathable and stretchy. I’ve worn the jacket running a couple of times and that definitely found the limit of the Fortius fabric’s breathability with it getting wet to the touch inside over 30 or 40 minutes of running in frosty temperatures. I was actually surprised that being a stretch-woven fabric it did not breath better, particularly considering it isn’t very windproof, nevertheless I also wore the jacket while slogging up 700 mtrs of ascent in Wales and only the Gore material sections were getting sweaty so at a slower pace the material does its job.
At the same time the Gore hood, shoulders and arms offer surprising amounts of protection in light rain, but it is dripping icefalls that the ACH seems really designed for. The steeper and more funky the ice, the more water dripping, dribbling and sometimes just pouring down from above becomes a factor. Here the Gore hood and yoke of the jacket work great - this is the area that takes the brunt of dripping ice whilst the softshell trunk and underside of the arms keeps you drier by letting perspiration out far more readily than a hard-shell does.
It really does work in its niche - the jacket is excellent to ice climb in.
The Gore sections protect against drips and even light rain from above, the Fortius material lets out sweat when you are working hard and makes the jacket very stretchy for athletic moves.
But how does it fair beyond that niche?
I think for British winter conditions it is better to think of the ACH as a softshell and to have a hardshell with you as well if wind-driven rain (or even wet snow) is likely to be an issue. But in that case there will be plenty of windproofs or softshell that are lighter (my ACH weighs 392 grams - a bit less than Arc’teryx claim) and cost considerably less and here we get to the question of whether the specificity of the ACH makes it not a great choice for UK winter climbers.
The ACH is great ice climber’s jacket if you are climbing predominantly in cold and dry conditions where what water you do come in contact with is generally from the dripping icefall you are attempting to climb. For some days in the British winter mountains the ACH will work superbly, but I would always be worried that if the weather turned and snow turned to rain, driven by the wind, it would not offer enough protection alone; in which case one of Arc’teryx’s many excellent full Gore-tex shells would be the better choice.
But if you do most of your ice climbing on frozen waterfalls or mixed routes in Alpine, Norwegian or North American mountain valleys - or like me, in Finnish forests - then the Alpha Comp Hoody works very well.
Ice climbers and alpine climbers move quickly, generate a lot of heat yet require waterproof protection from spindrift, water, and falling snow. Streamlined for light weight and energy efficiency, the Alpha Comp Hoody has a trim fit to maximize fabric technologies and provide clear lines of vision, with e3D (ergonomic, 3-dimensional patterning) to accommodate free movement of layers.
Fortius 1.0 stretch woven fabric regulates heat and provides stretch through core and sleeves. N40p 3L laminated Gore® Product Technology provides durable weather protection across the hood, shoulders, forearms and hem.
A helmet-compatible StormHood™ fits securely and adjusts rapidly with one hand movement. Zippered chest pocket and hand pockets are secure, accessible through equipment and straps and easy to operate while wearing gloves.
The refined two piece Hemlock™ inserts prevent jacket slippage, are compact and fold easily for storage.
For more information visit Arc'teryx Website
Toby is based in Finland. He describes himself as: "a writer and researcher specialising in international security politics; finally no longer a PhD student; hopeless but enthusiastic climber; part-time gear reviewer; keen multi-role cyclist; idealist and cynic"
Climbing keeps him from getting too depressed about politics. He blogs about both at: