Product test
Will this sleeping bag’s blend of wool and down win me over?
by Siri Schubert
Luxury feeling for outdoor adventures
13.5.2024
Translation: Elicia Payne
I’m fascinated by clothes and outdoor equipment made from innovative materials. So I had high expectations when I got my hands on a new creation by Grüezi bag – the Refreshful SilkWool Jacket made of silk and wool.
Silk and wool – that sounds like fine yarn. Not something for an outdoor jacket you’d wear hiking in the forest, across meadows and up mountains. Yet it’s exactly that which is hiding inside the Refreshful SilkWool Jacket by Grüezi bag, a manufacturer who has made a name for itself with its innovative wool-down sleeping bags.
I already tested their Biopod DownWool Subzero sleeping bag last year. I was impressed by how well it coped with moisture. Even on a wet meadow nothing clumped together on the inside of the sleeping bag and I slept warm and snug.
The search for the perfect combination
Grüezi bag founder Markus Wiesböck turned his focus to outdoor jackets and wanted to find an alternative to the popular synthetic thermal insulation material Primaloft. He also decided to use natural materials, wool and silk, for the filling to ensure a dry body climate and more comfort. Nevertheless, he spent quite a while tinkering with the product in Bad Feilnbach, Bavaria, until he found the perfect mix of materials.
The jacket couldn’t be too warm or too cold, especially in fluctuating weather in spring and autumn. It also had to be suitable for cool summer evenings and summer hikes. The first prototype contained too much silk and was too cool. Only after several attempts did he find the right mix. The filling now consists of 50 per cent European wool, 30 per cent recycled silk and 20 per cent Polyactide, a bio-plastic based on sugar starch. It was developed in Germany and manufactured in Portugal.
But it wasn’t just the insulation layer materials that proved challenging – the outer fabric also required a lot of attention. For a functional jacket to offer good insulation management, it needs to have sufficiently large pores to wick away moisture. Since silk cools more than the down-wool mix Grüezi bag uses in the Lightful Down Wool Jacket, for example, a fabric with better moisture conductivity, i.e. with larger pores, had to be found first. A special recycled nylon fabric provided the solution.
The jacket features practical details such as a detachable hood, an inside pocket, a chest pocket with zipper and two additional pockets. I really liked Sapphire Blue, but the jacket is also available in other colours such as bright pineapple yellow, cherry red or black.
Source: Siri Schubert
Why I don’t want to take the jacket off anymore
At around 350 grammes including the detachable hood, the jacket is lightweight and feels soft and silky. My first ten-kilometre hike was up a wooded hill. Normally on a hike like this, I’d constantly be taking my jacket off and putting it on again, because depending on the difficulty, I’d either be too warm or too cold. This wasn’t the case with the Refreshful SilkWool Jacket. I felt pleasantly warm and dry throughout.
On other walks and hikes in the Refreshful SilkWool Jacket I stayed the perfect temperature too. Thanks to the water-repellent outer fabric, the jacket protects you in a light drizzle. But, it’s not waterproof. When it’s throwing it down, the jacket works well as a mid-layer under a rain jacket.
I went for size L, although I usually wear a size M. That way I can move easily and can put on more layers underneath depending on the weather. If you prefer a tighter fit, you can of course choose your normal dress size, but it runs small.
I find the jacket so comfortable to wear that I no longer see it purely as an outdoor jacket. I wear it on the way to the office or to go shopping in town. Even when I’m sat on the terrace in the evening and it gets cooler, it provides the right smidge of extra warmth. The Refreshful SilkWool Jacket is a well-designed transition jacket for outdoor adventures and everyday wear. It’s also suitable for cool summer evenings or for breaks on longer hikes so you don’t get cold.
What makes silk and wool so special
As the jacket feels so comfortable, I wanted to know more about the materials. I’ve heard numerous times that silk is both cooling and warming. But how is that possible? I found the answer in a blog post by the Max Planck Institute (link in German). It says that silk has low thermal conductivity, which to a certain extent protects you from outside influences. When it’s cold, the heat from your body can’t escape because silk acts like a protective barrier. When it’s hot, the heat from the environment doesn’t penetrate your skin as easily.
But silk has another property: silk threads have tiny pores that can absorb and wick away moisture. When you sweat, the moisture is wicked away from your body and evaporates. The evaporation effect creates a pleasant cooling effect, leaving your skin dry. This is where silk differs to cotton. Cotton doesn’t wick the moisture away as well, so it sticks to the skin after sweaty activities.
However, silk alone doesn’t provide enough insulation for an outdoor jacket. This is where the second component of the jacket filling comes into play. Wool can absorb up to a third of its weight in moisture and wick it away from the body. It still feels dry to the touch and even warms when damp. Wool and silk are also odour-inhibiting, so the jacket stays fresh for longer. You can wash it by hand at 30 degrees, but airing it on the balcony has done the job for me so far.
In a nutshell
The jacket that adapts to you
The mix of wool and silk wicks moisture away from the body. Thanks to the insulation properties, you’re always the right temperature – even when the temperature outside fluctuates. The jacket is light and comfortable with practical details like the removeable hood.
I like it so much that over the past few months it’s become my go-to jacket whenever I leave the house. Be it for an evening stroll along the lakeshore or a longer hike at the weekend.
Pro
- suitable for spring, summer and autumn
- made from natural and recycled materials
- draws moisture away from the body
- good temperature regulation
Siri Schubert
Senior Editor
Siri.Schubert@digitecgalaxus.chResearch diver, outdoor guide and SUP instructor – I love being in, on and around water. Lakes, rivers and the ocean are my playgrounds. For a change of perspective, I look at the world from above while trail running or flying drones.
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