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Fjallraven Bergtagen Woolmesh Sweater

rated 5.0 of 5 stars
photo: Fjallraven Bergtagen Woolmesh Sweater base layer top

The Fjallraven Bergtagen Woolmesh Sweater is a base layer top that utilizes wool in three different weaves to maximize heat retention in key areas (chest, back) and breathability in others (stomach, underarms). It’s a total home run of execution and since I received this top for testing I have worn nothing else. It’s exceptionally well tailored, durable, doesn’t stink on multi-day trips, and you’ll have no fear around a fire. The only possible negatives are more inherent to wool, than this product—it takes longer to dry.


  • Comfortable
  • Durable
  • Breathable
  • Sleeve and torso length
  • No stink factor
  • Tight neckline (keeps snow out)
  • Fire resistant (no worry about sparks)


  • Wool takes longer to dry
  • No trail to town use
  • I usually prefer a base layer with a hood
  • I'd love to see thumb loops added




Fjallraven is right up there with Arc'teryx in the confusing naming scheme of their products. The Woolmesh Sweater is part of their Bergtagen line (Bergtagen is a Swedish word used to describe the feeling of being captivated and humbled by the mountains, awesome name), which includes the base layer (two top options and two bottom options, both men's and women's), mid-layer insulation (two different jackets for both men and women as well as an elephant style sleeping bag), outer shell (pants and jacket, both men's and women's), and a work layer (pants and jacket, both men's and women's).

So, as you can see, that's 21 product options all within the same name lineup. It can be a little confusing, even for someone who knows what they’re looking for. All are designed to mix and match, dependant on the conditions, and work together to create an ideal alpine kit. As someone who has only tested the base layer top and bottom, I can only speak to the quality of the garment as a standalone piece, and within a system of products that I (already owned) and paired it with.

Initial Impressions:

Upon receiving both the Bergtagen Woolmesh Sweater and Longjohns I had two initial reactions…

1) The packaging and presentation is beautiful. Both came in a fabric bag with a hard cardboard lining the interior. The garments were neatly rolled on the inside with a carabiner clipped to the outside (a little homage to the mountaineering designed line. Not a weight-bearing biner, clearly marked, but still good for clipping a chalk bag or gloves, etc).

A big part of Fjallraven's core values lie in sustainability and eco-friendly products and this is a wonderful demonstration of that. I still use both bags, one I kept the cardboard in and it’s an extra layer of hard sided protection for my camera when in my pack, and the second I pulled out the cardboard and just use it as a ditty bag—keeps my lip chap, knife, extra batteries, headlamp, all in one place. Nice touch, Fjallraven.


2) Once you get past the Apple level enjoyment of the packaging you pull out the garment. It’s shocking at first, and not necessarily in a good way. I remember pulling it out and laughing. I felt like Barney Stinson from the "Murtaugh list" episode...Google it. 

The problem is each time you wear it you’ll love it more than the last time... Unless you're coming off a cold winter trip and just want to stop for a bite to eat on your way home...and take your jacket off...and realize you're siting in a restaurant in a mesh bellied top...don’t happens.



In a word? Ideal. I’ve found every dimension of this top to be to a well tailored suit. Tight, without being restrictive. Long torso length that allows you to tuck it into your pants, which is fantastic in sealing off any gaps, especially when wearing a harness, as they usually make layers ride up. The sleeves are nice and long also with a nice tight fit around the wrists that doesn’t interfere with chunkier gauntlets on gloves or mitts.

The neck area is small (and this may be a negative for some). I have a 16 1/2-inch neck when purchasing a dress shirt. Yes, I know it's like a giraffe neck, so it fits my skinny neck nicely without allowing any inadvertent snow in. I would imagine it would eventually loosen and stretch if you have a larger neck, but it’s worth noting.

I’m admittedly a bit of a baby when it comes to itch factor and this thing is soooooooft. I often use wool as a mid-layer and not a base layer because, well, the baby thing, and most of my base layers are synthetic, but this thing feels like your genetic grid pattern fleece, but with more positives. The amount and percentage of wool varies within the three different patterns used (more on that below) but all are comfy soft.

Probably the most impressive thing is the use of three different wool blends, and patterns, throughout the piece. The chest and shoulders have a thick(er) grid pattern (and polyester for durability) to maintain core temp. The back and underarms have a wool mesh (hence the name) for more breathability, and the low profile, but dense weave used at the hem, wrist, and collar. More info on the wool construction, and percentages, below.


This photo is my attempt to best demonstrate the three different wool types. The far left is the mesh breathable area, top right is the low profile used for cuffs and collar, and the bottom right is the high loft, almost like a grid fleece used to keep the core warm.

9A145F3D-8EB1-418A-A983-F0AC35788E56.jpgInterior view of the lighter grey, high loft area


Now this is where things go above my pay grade. I genuinely don’t know how this product works so well. These two headers, while not mutually exclusive, generally, are at odds with one another. If something is highly breathable than you can assume it can’t trap heat that well and vice versa. I have yet to find a lower limit to these things as a base layer and that’s saying a lot as they’ve seen temperatures below -30°c with a wind chill.

Now I was wearing appropriate mid and outer layers (obviously), with these but I’m still baffled. You’d expect the mesh areas of these to be noticeably colder than the other two sections. Somehow though, you don’t notice a difference at all. You also don’t end up up hot and sweaty, as long as you are taking appropriate venting steps and helping to regulate your core temp, but that is something you need to do regardless of what type of base layer you choose.

Being wool the Bergtagen can absorb a lot of water weight before you even begin to feel clammy. The high wool content throughout all three of the materials used will pull moisture away from the skin, although as is common with wool, it can take longer to dry once wet. I’ve timed it at somewhere in between 10-12 hours without a heat source, and 2-3 with one, so a fire, or hot tent, comes in handy, and another bonus of the wool is no fear of sparks, or embers, from a fire.

I usually like to wear my base layers into my sleeping bag, especially on mountaineering trips where extra weight carried becomes exponentially worse, and any moisture in a down bag is generally no bueno. A little preventative caution to manage moisture and you’ll be fine.

Where the breathability shines is in the mesh areas (back, underarm, and stomach). Having a full mesh back when carrying a pack is just short of game changing. Carrying heavy winter loads, or under extreme circumstances, can cause a lot of perspiration, especially when given no way to escape. Having as little fabric on the back portion allows this garment to expel as much as possible.



The best part about a wool base layer? You don’t get that chill when you stop for a break. Wool is incredible at maintaining a micro climate around your body, so you don’t get those temperature swings from too hot to too cold.


Exactly what you’d expect from a company who has built its name bucking the ultra light trend in favour of durability and sustainability. Seams are stitched straight and tight, flat locked, with no loose ends or exposed threads. Over four months (and numerous uses), multiple washes (cold wash, always wool specific detergent, and hung to dry) the garment looks almost brand new.

I say almost because the bottom hem is starting to curl a little. It’s purely cosmetic, and doesn't effect the function at all. It does seem to have shrunk slightly—I think my wife put it through the dryer once—but it stretches out after a couple hours of wear.

There’s been absolutely no pilling along the edges, even the high wear areas around the cuffs. Wool, when treated properly, should last a long time and I see no reason that this product won’t, especially given the high wool content throughout. In case you're wondering, the three different wool blends break down like this:

  • chest, shoulders: 52% wool, 35% polyester, 13% nylon
  • sleeves, sides, low torso, back: 80% wool, 20% nylon 
  • side panels, cuffs, neck: 95% wool, 5% elastane



A base layer should be relatively low bulk and should play well with others. This checks both boxes. Anywhere that it would meet another layer (wrist, hem, collar) a tight thin weave is used. Tucking in a wrist gauntlet on a mitt, or into the bottom into pants isn’t a problem. The back having mesh, as well as the underarms, allows for free range of movement as well as minimal stacking of layers. The wool slides nicely, even when using a wool mid-layer, and the extra long length doen’t allow for any cold air gaps.

5838E3D3-A182-4CAF-A1BD-9286C1594C01.jpgYou can see here, even with a jacket with a built-in wrist gaiter, the Bergtagen still plays nicely with others.


Any product designed for mountaineering or winter camping needs to be hard wearing, durable, and reliable. The Bertagen Woolmesh Sweater is designed to be exactly that—exactly what you need, where you need it, and nothing more. It has clearly been designed, and tested, by people who use it. The quality of the product, the thoughtfulness of the design, and the use of cohesive different fabrics makes this a winner of a product. I own multiple base layers and now only reach for one—this one.



I’ve tested the Fjallraven Bergtagen Woolmesh Sweater over a four-month period here in Ontario, Canada. We’ve seen temperatures as low as -30° Celsius not accounting for the windchill this winter. The warmest temps I reach for this are around 0°c, and that’s because you need a layer over it (to hide the fact that you're wearing a mesh top), but it works well with just a shell, especially in a cold rain.


My thanks to Fjallraven and Trailspace for the opportunity to test the Bergtagen Woolmesh Sweater.

Source: received for testing via the Trailspace Review Corps (Sample provided by Fjallraven for testing and review)

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