New this spring, the Berghaus Hyper HydroShell Jacket is, almost certainly, the world’s lightest full-zip waterproof jacket weighing in on our digital scales at a gob-smackingly light 77 grammes for a medium.

That’s lighter than most lightweight windproof and only a little heavier than the super-minimalist Vapour Light Hyper Smock 2.0 with which it shares fabric and construction technology.

The fabric is Berghaus’s own-brand Hydroshell Hyper fabric, a shimmering, semi-translucent Polyamide – Nylon – with a thin PU coating. The seams get the high-tech treatment too using an exclusive ultra-lightweight seam tape to save precious grammes.

Fabric and technologies are common to the Hyper Smock 2.0 but the full-length zip increases all-round usability slightly – note simple tab for hood stowage.

Minimalist Features

The neat, close-fitting hood, cuffs and hem are all stretch Lycra bound – ‘elasticated’ – to save weight and while that means none are adjustable, so far we’ve found the fit on all openings fine. There are, by the way, no pockets, not even a token one to take a spare tenner or a house key, but that’s minimalism for you.

Which sort of begs the question why you’d choose the jacket version over the even lighter smock. Most racers checking off a mandatory tick-list won’t, we reckon, but the jacket does have some advantages.

For a start, that full-length zip, backed with a substantial storm-flap you’ll be glad to hear, makes the jacket easier to get on and off than the Smock and offers some extra venting potential – sleeves roll up to the elbows as well.

The giveaway MtnHaus label on the inside of the zip storm-flap indicates that the jacket was developed by the crack MtnHaus design team behind many of the brand’s best products.

More Space Inside

And then there’s the cut, our first impressions are that it’s a little more generous than the smock version around the torso leaving room for extra clothing layers or even extra wearer, which arguably makes it more suitable for lightweight backpacking rather than running or racing use, than its partially-zipped cousin.

It’s tiny too, packing into its neat little 5-gramme stuff-sac to make a package around the size of a tennis ball or a small apple. Ideal for sticking in a lid pocket, bum-bag or stash-pocket just in case.

If you do need it though, it will do the business and has been carefully refined compared to the first generation smock. The hood for example, is properly head hugging to ensure it stays in place even in wet and windy conditions and even features a minimalist stiffened peak for a little extra eye protection in the wet. Impressive micro-design…

Pack size is impressively tiny – think small apple. For perspective, this is it next to a standard-sized business card.

‘Just In Case’

And ‘just in case’ realistically is what the Hyper Hydroshell is all about. Our previous experience with the Smock is that it’s wind and waterproof all right, but less breathable than some alternative fabrics, which makes it great for those days when you think it might just rain but aren’t sure, but not a shell you’d choose on 100% rain days.

To be fair, Berghaus athlete Philip Gatta used his first generation Hyper Smock rather more extensively than that on the 1200km Great Himalayan Trail and the fabric is, we think, rather less fragile than you might imagine, but for most of us, it makes more sense as a ‘sometimes’ option.

If that’s what you’re after though, the Hyper HydroShell fits the bill brilliantly. Stick it in your pack, bum-bag or jersey pocket just in case knowing that it’s genuinely waterproof if you do need it.

Shimmering, semi-translucent fabric and ultra-narrow exclusive seam tape are at the core of the jacket’s impressively low weight.

Initial Verdict

Hardcore gramme-counters will probably still opt for the even lighter Hyper Smock 2.0, but the new Hyper HydroShell Jacket adds a little more all-round usability thanks to the full-zip format and slightly more generous cut, while still being ridiculously light and compact thanks to the MtnHaus-developed fabrics and construction.

A brilliant emergency waterproof with a minimal weight penalty, which means you carry it in situations where otherwise you simply wouldn’t bother with a waterproof at all.

Pros

Insane light, tiny pack size, full-zip opening, waterproof, rollable sleeves, surprisingly generous cut, excellent, close-fitting hood.

Cons

No pockets, average breathability, surprisingly generous cut, not specced for durability.