I recently walked 60 kilometres across the Black Mountains, ascending almost 3,000 metres, in just 29 hours. It was far from ultra-marathon pace, but my 27kg pack wasn’t your average ultralight burden, either. And while I’m in no hurry to do it again, what this adventure did imbue in me was a desire to hike further and experience more. 

Ditching the Bergen for a much lighter pack is a non-negotiable, however, and so off I went in search of something more manageable. Luckily, Colorado-born brand Big Agnes has recently released a new ultralight range in a neutral grey/pale sage green that goes with just about anything. Hesitant of making the same back-breaking mistake again, I opted for the smallest of the three – at a humble 28 litres. The larger 43L and 60L options are almost identical in design. 

Described by the US manufacturer as an ‘ultralight running vest style daypack’, it sits in a convenient space between a running and hiking pack. It’s large enough for a compact sleeping system and maybe a few rations (but not much else), and thanks to the running-vest-style straps, can be cinched securely enough to the body to move at pace. Recycled nylon derived from discarded fishing nets is partially responsible for its lightweight nature, with both S/M and M/L sizes weighing in at well under a kilogram. Other materials contributing to Big Agnes’ sustainability credentials include recycled foam and webbing.

Sphere score

For

• Lightweight at just half a kilo in the S/M size. 
• Removeable waist strap 
• Minimalistic design
• Eco-conscious construction 

Against

• Cord is quite faffy
• Pale colour will likely stain and show dirt easily
• Lack of other colour options
• Doesn’t come with flasks or a hydration bladder
• No hip belt pockets

Tech Specs

• €200/£169
• Two sizes – S/M, M/L
• Capacity – 28L

What does the Big Agnes Ultralight 28L have to offer?

Big Agnes has made its name in the ultralight industry, and this latest offering is born from two decades of experimentation and innovation. 

It’s lightweight and minimalistic, with just enough pockets to be practical (I say ‘just enough’, but a hip belt pocket wouldn’t go amiss). Inside the 28-litre main compartment is a sleeve for a water bladder (not provided), while inside and outside the top flap are handy pouches for smaller items (the former also stores a detachable rain cover).

But perhaps most useful are the stretchy mesh pockets on the front and sides of the bag, and the smaller pouches on the chest straps – perfect for a phone and snacks or a small water bottle. When speed is key and time is of the essence, these are a quick solution to stashing gear on the go. This is especially helpful when you consider the awkwardness of the pack’s cord fastening system – while it works perfectly well and feels secure, it can be hard to get right, especially when it comes to tidying up the loose ends. 

The 28-litre top-loading main compartment is adaptable in capacity, with a spindrift collar that extends upwards, providing extra space when required, and protection from the elements for the contents when not. Even with a day’s worth of warm kit and climbing snacks, there was still space to spare, but it’s a feature that would undoubtedly come in useful for multiday fastpacking. 

Wearing – what is the Big Agnes Ultralight 28L like?

At 5ft7 and relatively evenly proportioned, I’m a comfortable size S/M, with the smaller of the two options claiming to fit a torso length of 38-46cm and with a (removable) hip belt spanning 64 – 117cm. Weighing in at 829g, it’s only a fraction lighter than the M/L,  which claims an empty weight of 907g, and fits a torso length of 46-53cm, with a 71 – 122cm waist belt.  

The main compartment itself is suitably low-profile, meaning that with correct load distribution the weight hugs your body and sits comfortable spread across your back and hips – Big Agnes claims its ‘injection-moulded, anatomically-curved frame sheet’ adjusts to your back, and I can’t disagree – certainly not on first impressions, anyway.

What the pack would benefit from, however, would be slightly more adjustability in the top of the straps, which would allow you to redistribute the weight on your shoulders. Both the 43 and 60-litre variants feature ‘load lifter’ tightening straps atop the shoulders, which would also be handy on the smallest option if you’re planning on carrying weight. 

Regardless, provided you’re not too weighed down, the running-vest inspired straps, complete with dual sternum straps and hip belt holds the pack secure. Correctly adjusted, it was comfortable at everything from an amble to a jog – the latter thankfully making minimal rustling, too. 

To finish

Big Agnes hasn’t previously been in my go-to hiking gear – purely due to its smallish profile in the UK – but this may well be the turning point. The Sweetwater UL 28L has everything I look for in a pack, with only a few minor inconveniences – faffy cord closure system, lack of hip belt pocket, and only one (susceptible to staining) colourway.

I haven’t yet put it to the test on a longer expedition, but with summer in full swing and new challenges afoot, I look forward to testing the Sweetwater’s limits.