Review: Mammut Crag IN Jacket

The combination of 100 percent recycled PFC free DWR coated polyamide outer shell and plenty of wadding (9.5-ounce / 270-grams fill weight) makes it a great choice as a daily cold weather jacket whether walking the dog, gardening, hiking local trails or just hanging out. And with a respectable level of water resistance, and lack of natural fibres, there’s no danger of the insulation losing its warmth in the rain. The outer fabric has a 20-denier thickness, which is durable and at 15.9-ounces (452-grams) it is a comparable weight to plenty of other jackets around this price point, but it certainly won’t pack down as small due to the density of the insulation wadding.

Rope strands are brushed together and mixed with recycled plastic to create a roll of highly insulating, completely recycled wadding.

Photograph: Mammut

I was impressed with how easy the Crag IN jacket was to wash. Because the insulation is a sewn-in sheet, rather than loose fill, it holds its shape easier and doesn’t clump after a standard 30° C machine cycle. As such, I can imagine washing it more frequently than my traditional puffer jackets, although being polyester, there remains the annoying issue of microplastics in the water system.

When I asked Helena Theba, Material Management Lead at Mammut, she told me that the Loopinsulation insulation had “impressive technical properties that are directly comparable to industry standards like Primaloft Gold,” but did also “recommend other insulation with higher loft for high-output alpine activities.” And this is a fair point, and one often overlooked by the general buyer who is arguably too quick to reach for the most technical outerwear regardless of whether it ever gets used as the makers intended.

Photograph: Mammut

For the 2024/25 season Mammut has launched a couple of other options featuring Loopinsulation. These include the impressively versatile 2.5 layer Alto Light 3-in-1 HS Hooded Jacket ($369), which is both waterproof and insulating, while the Sender IN Hooded Jacket ($259) has 11.6-ounces (330-grams) of old rope insulation and a more versatile, climbing-specific stretchy shell made from recycled polyester and Spandex.

I’ve been wearing a battered old Patagonia Nano Puff ($239/£190) for years (alongside many other jackets that come through the test bench), and this too is made from 100-percent post consumer recycled polyester. As someone who prefers to layer up rather than rely on one thick jacket, I don’t think the Crag IN will become my go-to choice, mainly due to the boxy slightly stiff fit. But as a super-warm multi-purpose jacket that’s windproof, comfortable and a brilliant example of closed-loop, open-minded recycling in action, it is hugely impressive.