Alex Roddie reviews a well-featured down sleeping bag that makes a decent option for milder winter use in the UK hills.

The Robens Couloir 750 – which received a silver award in our 2018 Gear Awards – is a warm and reasonably light sleeping bag filled with 700 fill power hydrophobic down. I’ve been using it for backpacking in the Scottish mountains over the winter season. Although not the lightest option, it offers a good all-round package.

Robens say the Couloir 750 has a “Technical Mummy profile with a Toray nylon Taffeta shell to ensure performance”. The design is certainly well thought-out – I particularly like the centre zip, which (although by no means exclusive to Robens) is very convenient for use in the cramped confines of a single-person tent, and eliminates the need for separate right-handed or left-handed models. The centre zip has a very effective double baffle that prevents heat loss. In fact, the baffle is so good that it can prevent drafts even if the zip is left partially undone. This does mean that you have to undo more of the zip than you might expect to vent the sleeping bag in warmer conditions. One downside with the zipper is that when it’s pulled up right to your face the zip can sometimes come into contact with your skin – it pokes between the baffles – which can be a shock if it’s cold!

Otherwise, the design is good, with a roomy fit and a very good ‘shark fin’ footbox with loads of room for both your feet and your fluffy sleeping socks of choice. The hood is also very roomy with excellent adjustment toggles and a generous shoulder baffle. I’m 5’6″ with average build and I can easily wear several additional layers inside this sleeping bag, including a down jacket if necessary.

“Sleeping bag warmth is highly personal and varies night by night depending on multiple factors, so take this with a pinch of salt, but I’ve been warm enough at -10˚C wearing base layers”

There’s no mention of a DWR treatment for the outer nylon shell, but it’s fairly good at keeping light condensation or drips away from the down – which, luckily, is hydrophobic anyway, making this far less of a concern. In all my nights camping with this sleeping bag, often in heavy condensation, I have never experienced issues with loss of loft due to moisture.

The hydrophobic down certainly works. But Robens make no mention of the down’s provenance, ethical or otherwise, which is something to consider as many other manufacturers take steps to ensure their down is sourced ethically.

A further downside is that the down only has a fill power of 700, which is far from the best available. This contributes to a higher weight than competing bags offering a similar warmth. However, at a measured weight of 1.22kg (lighter on my scales than the manufacturer’s claim of 1.39kg), it’s still quite reasonable for winter backpacking.

Let’s talk about price. At £379.99, price is on a similar level to lighter options at a similar warmth from other brands, which makes it a little expensive for what you’re getting.

It comes with basic accessories: a rather poor, non-waterproof stuffsack that I immediately replaced with a drybag, and a roomy mesh sack for storing the bag uncompressed (recommended to help extend the life of your sleeping bag).

On the trail in Knoydart
Image © Alex Roddie

On the trail, this sleeping bag performs well. It compresses down small enough to comfortably fit in a winter pack, and the weight is fine in winter, even for a gram weenie like me. The bag lofts quickly enough after compression although it does benefit from being shaken to help redistribute the down (this is easily done with your fingers if you experience any clumping – I have had no issues with cold spots).

Robens give a women’s comfort limit of -8˚C and a men’s comfort limit of -15˚C. Sleeping bag warmth is highly personal and varies night by night depending on multiple factors, so take this with a pinch of salt, but I’ve been warm enough at -10˚C wearing base layers (I sleep fairly warm) and lying on an insulated 4-season mat. Anything below freezing is toasty for me. Above 1–2˚C and I need to vent; above 5˚C and I need to use it as a quilt to avoid overheating. With this in mind, I’d say it’s suitable for the majority of UK winter wild camping in average conditions, although in the coldest weather it may not be warm enough and you will want additional insulation.

Overall, this is a good winter sleeping bag offering great performance, effective design, and an acceptable pack weight. However, there are lighter options out there offering similar warmth at a similar price, making it less cost effective than some competing bags.