Kora ‘Xenolith Sweater’


Greetings Adventurers!

Six months ago I received a new garment called the ‘Xenolith Sweater‘ from Kora, a UK based company that specializes in high-end garments – primarily for those who are doing expeditions and epic adventurers in some of the most awesome places that we humans go here on earth.

I have previously reviewed the Kora ‘Shola 230’ Leggings and the Kora ‘Shola 230 Zip’ Top, with the latter of the two being, by far, the most popular of the two garments. I have often responded to folks wanting to know my thoughts about the Shola 230 Top with: “the Kora Shola 230 Zip is the best warmth to weight ratio top garment that I have used“. I did ding the 230 Zip in a few ways but gave it significantly more praise than counter praise. It is an amazing lightweight layer 1 or L2 thermal garment for the typical day to day conditions that I face here in the Redwoods of Northern California. Likewise, the 230 leggings have been my go-to thermal bottoms since I got them.

Over the last, almost two years now, I have tried to stay devoted to putting the test to Yak wool products, from Kora as well as other companies trying to make a go at making Yak wool garments. This has not been easy. A lot of these garments made from Yak wool are hella expensive, often times a third or more expensive than their appropriate counterparts in the Merino wool market. It has also not been easy because I have encountered more than one company making Yak wool garments that have just turned out to be horribly disappointing in the durability world of things. And lastly, in the things that have made it hard to do long-term garment testing on Yak wool products is the simple fact that there is not a lot of them on the market.

Over the last two years I have stayed in contact with the folks at Kora and sometime in mid-2017 I was having an email conversation with them and the opportunity to acquire this ‘Xenolith Sweater‘ came up. So when they offered to send me one to put to the test, I jumped at that opportunity – hell yes! For the haters out there, full disclosure: I did not pay for this garment, and I am not sponsored by Kora. In the past, I have written good things about Kora products, and some negative things about Kora. I keep it real and honest. They respect that. Most folks seem too as well. I have already given them feedback on a few things about the Xenolith garment that may or may not result in changes to a future update of the garment, most of which will be discussed below.

So introduction part of this article finished, let us move onto to the nitty gritty goodies!

The Fabric Tech:

Let me just say this at the very beginning:

The Kora Xenolith is the most technologically advanced garment that I have ever worn!

The Xenolith is:

  • 240gsm
  • 70% Merino Wool
  • 30% Yak Wool
  • Polartec Alpha
  • 50gsm mesh lining

Wait… did you catch that?

70/30 Merino/Yak wool… and… Polartec Alpha.

Say What!

We All Love Wool, Right :)

Ok, maybe not my hardcore vegan friends, but I know you all will forgive me. And I know that my Levitican 19:19 friends will forgive me too.

Like many of the Yak wool garment companies, Kora has made the change away from 100% Yak wool and gone to a blended fabric, primarily to gain some much-needed durability with the Yak wool. I was a bit surprised that Kora went with the 70/30 merino/yak and not the other way around with a 70/30 Yak/merino. But, it works. It really really works.

From a durability perspective, I am happy to report that it has proven to be without any issues. Given the 240gsm and the high percentage of Merino wool, that is not to be a surprise.

Polartec Alpha!

Here is an inside-out photograph of the xenolith sweater showing the Polartec Alpha regions of the garment – brilliant.

Then there is that part in there about Polartec Alpha. If you don’t know, you should. Polartec Alpha is, in the world of synthetic sheet insulation, the Lamborghini, the Aston Martin, the Bugatti.

The Polartec Alpha synthetic sheet insulation is located along the entire back part of the body of the sweater going all the way up to the top of the shoulders, as well as well as along the sleeves to about the elbow region.

Why Polartec Alpha?

Polartec Alpha introduces a number of major advantages to a mid-layer, mid-weight, garment like the Xenolith.

First, it is an excellent synthetic sheet insulation. Very likely the finest synthetic sheet insulation that exists.

Second, it offers awesome air permeability, watch this video showing Polartec Alpha compared to Primaloft Gold. With a garment like this, you want it to vent, but you also want it to stay warm – and keep you warm – yet not vent so much air that you lose natural thermoregulation abilities. In this, they have masterfully succeeded.

Polartec Alpha has been used by a number of big name brands over the last few years including Marmot and Outdoor Research, so it is really great to see a smaller company like Kora integrate it into their garment lineup! Arc’teryx has spent a boatload of R&D money trying to make a viable competitor (their ‘Coreloft’) and I am pretty sure that Patagonia has spent even more with their Polartec Alpha competitor ‘FullRange’.

As Kora writes on their website:

Polartec Alpha is a hi-tech alternative to down and fleece insulation.

Unlike down, it’s extremely breathable, insulates even when wet and dries quickly.

Unlike fleece, it packs down small. It’s quiet too – no rustling noises as you move.

It is no great secret that I am a 100% synthetic hiker. I have been for a few years and just see no reason to return to using animal down. See my Why Synthetic? article for more on that. So when I saw this garment had Polartec Alpha, it just sent it through the roof on the OMG scale. A freaking wool garment that has Polartec Alpha insulation… seriously, OMG. Yes please, mommy.

So, does it work?

Well, for the last six-plus months I have been living in this things. I do not remember a single day when I have not had it on. It is just brilliant.

Only twice have I gone “dang, getting a little warm wearing this thing” and found I needed to take it off. Both those times the temps had reached into the mid F70° (C21°) range and there is really no reason to be wearing a sweater in those temps, it was just a matter of the midday temps sneaking up on me.

On far more occasions I have been wearing it and thought to myself “Wow, this really works!” A number of times I have been down near the freezing temp range and found myself wearing only a merino wool t-shirt and this Kora Xenolith. One of the times when that happened is when I was out on the hike when I shot my Creek Coffee video (starts at 2:00 mark) temps at night were subfreezing and when I shot the video they were not much above freezing, yet I was able to be out there wearing only a thin t-shirt and the Xenolith.

So, does all this fancy dancy fabric blending and hella expensive tech work?

YES! Absolutely. And I am not just saying that to say it. It really does work. No BS here. Somehow all of this works. It actually does make the $250.00 price tag for this sweater make sense. I sure did not understand the price tag when I first saw it. Having now experienced what they have been able to accomplish with this garment, I get it now. This is a garment that somehow keeps you warm in the cold and just perfect in those temps up to where you normally should just not be wearing a sweater – and it does so without causing you to overheat when you should not. It is brilliant, just brilliant.


So in keeping things real, a few things that have made me go “meh


meh, a mid-layer garment should not have a chest pocket imvho.

First, is that it has a chest pocket. Folks that have followed me for any length of time know that I do not like, and downright loathe, chest pockets on mid-layer garments. Chest pockets have no place on mid-layer garments. Hardshell garments, sure, go for it – I will still complain about them, but at least I can get behind the purpose of chest pockets on hard-shell garments. But can we please stop putting chest pockets on mid-layer garments! The only saving grace in all of this is that Kora put the chest pocket access on the inside – so none of that stupid zipper/pocket crap on the outside of the garment. In the six-plus months that I have owned the Xenolith, I have never put anything inside of the pocket. I have never even opened the zipper on it except when I first took it out of the package.

Second thing on the ‘meh’ list, keeping it real, is that for the first few weeks until the fabric softened up a bit, there was a bit of rubbing on my elbows due to a rather strange twist of the seam line on the arms. Unlike any other garment that I have owned, Kora and their design team have designed the seam line to not go in a straight line down the length of the arm, rather it has this unique pattern that has it start at the top-center of the shoulder, than slightly twist until it reaches the middle part of the sleeve around the elbow. After the garment softened up I rarely found it to annoy me. These days as I near the 200 days of wearing the sweater the only time I notice it is if I happen to have my elbow resting on something (desk chair, for example), the seam line is right where my elbow is. But, all of this is absolutely 100% a non-issue in the real world of things. I think it is something that has bothered me maybe twice since the first week or two of wearing it. But still, keeping it real on both my loves and my meh’s of this garment.

Next, I wish the arm lengths were a bit longer. But this is an issue with pretty much every long sleeve top garment that I put on. The rest of the garment fits me perfectly. I just need another two inches of arm length.

And, lastly, I really do wish that the Xenolith was a full-length zippered garment. I am just not a fan of pull-over garments. I am not saying this is a ‘negative/con’ of this garment per se, after all a lot of tech sweaters are pull over – but I just prefer full zipper garments, even if it means an extra half ounce or so on the scale. If there was any one thing that I could change to the Xenolith, as much as I loathe those stupid chest pockets, having the Xenolith having a full-length zipper would be the priority, number one, on my want-to-see-changed list. But, I totally understand there are a whole bunch of folks out there that like pull-over sweaters. I am just not one of them.

Features of the Xenolith:

In regards to features, this is a fully featured top garment with all of the bells and whistles that you would expect from a top-end garment.

Copied this from their website, for if they ever update their website, we have an archive of the features of the version that I have.

Lightweight technical mid-layer

Exterior layer of Hima-Layer Yardang 240gsm (70% merino, 30% yak wool) with four-way stretch for added flexibility

Polartec Alpha

Light, durable 50gsm mesh lining for enhanced breathability, stretch and durability. (66% nylon, 34% elastane)

Cut to fit close to the body. Designed to fit perfectly over Kora base layers without ruching or adding bulk

Arm holes are cut to allow you to extend your arms without making the rest of the garment ride up. Body is cut longer at the back to keep you covered when you sit or bend

Integrated thumb loops – can also be pushed up to the wrist

Zipped inside pocket for stashing valuables

Deep centre front YKK zip can be opened to release excess heat. An internal zipper guard prevents the zip catching on base layers

Collar is insulated for extra warmth, but fits comfortably underneath a shell layer

Kora insignia on wrist and embroidered logo on outer layer of neck, so they won’t irritate your skin

Sweater Weight:

Kora does not list the weight of their garments on their website, which is unfortunate, but understandable, few companies do these days it seems.

I have a size medium and it is 471 grams / 16.6 ounces / 0.0074 stone.

If we compare that to another high-quality top-end garment, the Icebreaker Descender Long-sleeve half-zip (as close to the Xenolith as Icebreaker has, without the Polartec Alpha of course), it is 321 grams / 11.3 ounces / 0.0505 stone. So in exchange for a lot more tech (btw, the Descender is $190.00) and Yak wool instead of a bunch of plastic, the weight difference is 150 grams / 5.29 ounces / 0.023 stone.



Layering with the Xenolith:

So what is my approach to layer with the Kora Xenolith?

Fairly simple for the most part, and this is how I have approached it almost from the beginning.

Next To Skin: the now discontinued NWAlpine 100% Merino Tech Tee.

L1: This Kora Xenolith

L2: The Montbell ‘U.L. Thermawrap Jacket’.

L3: The Enlightened Equipment ‘Copperfield Wind Shirt’.

The exception to that layering system is when I am expecting things to be just a wee bit cold, in which case I have switched things up to this layering method:

NtS: the now discontinued NWAlpine 100% Merino Tech Tee.

L1: The Peak to Plateau ‘Kailash 1/4 Zip’.

L2: This Kora Xenolith

L3: The Montbell ‘U.L. Thermawrap Jacket’.

L4: The Enlightened Equipment ‘Copperfield Wind Shirt’.

L5: The Enlightened Equipment ‘Torrid APEX Jacket’.

There have not been too many nights when I needed to go with that full six layering system, but I was glad to have all of that thermal gear with me for the few exceptions.


Next To Skin Wear:

So that leads to the question of how does the Xenolith perform as a NtS garment?

Somewhere around the second month of wearing the Xenolith, I tried giving it a full-time usage as a NtS garment. That lasted about 10, maybe 12 days. It felt wonderful. But I have just become so accustomed to wearing a t-shirt (2000+ days of wearing an icebreaker tech tee) that I just instinctively started putting on my t-shirt first, and thus broke the cycle of wearing the Xenolith as a NtS.

The Xenolith could easily be a NtS garment. It feels great, handles thermoregulation brilliantly, has zipper guards on the inside to prevent chest hair pulling, a cold zipper against your chest, and air drafts. It checks off all the necessary check boxes for a NtS sweater.


Other Thoughts:

In regards to the garment shrinking after washing it: Kora states you should expect a 5% shrinking, but so far that is not something that I have noticed.

I have been very impressed with the zipper. Would be lovely if it was a full-length zipper, as I stated above, but the zipper is nice and strong.

That is all for now. I will update with any additional thoughts should they come to mind.

Unboxing Video:

Back when I received the Xenolith from Kora I shot an unboxing video. I never released it and figured I might as well attach it to this initial article on the sweater. Obviously, a few things I mentioned in the video are different from how they are now, such as my approach to layering the sweater, but for those wanting to waste 20-odd minutes watching some random video on the garment, here ya go!



Where To Buy:

You can buy the Kora Xenolith Sweater directly from the Kora website:


One thought on “Kora ‘Xenolith Sweater’

  1. I’ll admit I’m somewhat mystified by the use of Alpha insulation along the back. With a pack on, breathability along my back is often reduced significantly, as most packs don’t have a very breathable back panel, with some exceptions.

    With this in mind, i would think that putting a layer of Alpha back there would make my back even more sweaty when hiking with a pack on.

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