It was therefore a real mind-opener to me (and I believe to many others) when the Polartec Alpha fabric came out.

In harsh, snowy mountains, it’s really annoying to put on and take off various layers to adjust for rapid temperature changes. Ideally, I prefer not to change my outfit at all until the end of the day, and Polartec Alpha made this possible.

Polartec Alpha is ideal because even though it is a synthetic insulation material, it has superior breathability that makes it perfect for strenuous winter hiking.

It is a dream material not just for hiking, but also when sleeping in a tent on a snowy day and even on the way back home it keeps you warm. But I couldn’t find a product matching my standards in terms of function and design using this superior fabric, so I decided to make my own.

As mentioned in the product story for our Winter Hike Pants, pockets are the key feature for good winter hiking wear. You don’t want to take down your backpack to get snacks or maps. Especially when it’s windy and cold. So handy and large pockets are a must. The warm pockets are also beneficial for digital devices such as smartphones and cameras to extend battery life.

In addition to the material’s superiority, winter clothes must be properly designed to deal with the radical temperature difference in winter. Polartec Alpha always offers comfort during activity and you can keep wearing it even when sleeping. But if the jacket is designed only for wearing while on the move, it might be too thin and cold when the temperature drops. On the other hand, if it’s too thick and warm, it can easily get too hot when the sun is shining.

My ideal was a jacket that could provide maximum versatility for all the various situations during a winter hike.

We started the product design focusing on this versatility. We adopted the updated version of Alpha, the Polartec Alpha Direct with even better breathability and fast-drying performance. Regular Alpha requires a back liner just like conventional synthetic insulation, whereas Alpha Direct is much like a fleece material and does not need any lining, and consequently has even better breathability than the regular Alpha fabric.

For the surface material, we used the lightweight, durable, and highly breathable Pertex Quantum Air to maximize the advantages of the Alpha Direct fabric.

The large kangaroo pocket is divided into two compartments, and it has even more capacity than our Sacoche. You can easily stow items such as maps, snacks, and gloves in the pocket, and the insulation also helps to keep your digital gadgets warm. At the pocket, we decided to add two layers of Alpha Direct for additional warmth around your waist. (See product story of the Merino Hoody (the old version Updated 2021)

for why it’s important to keep your belly warm when hiking in winter.)

To manage the radical temperature difference during winter hiking, we added wide ventilation openings on both sides. Though Alpha Direct is highly breathable, you may get overheated during strenuous exercise. Even in a situation like this, you don’t need to take the Anorak off. Instead, you can control the temperature by enlarging the ventilation openings. When the weather is rough, the high collar protects around your mouth and nose and the thumb holes help to keep your palms warm.

After numerous field tests, we decided on the current Anorak design and I really believe it’s the ideal jacket for winter hiking. As with our Winter Hike Pants, you don’t have to change your clothes during the hike because of the Anorak’s highly adjustable ventilation openings.

2017

When I was looking for a new fabric, I thought that thermal clothes should be as breathable as possible, because good ventilation was supposed to create better comfort when on the move. Some companies released new ultra-breathable products using new materials such as Primaloft Next or Octa with no outer fabrics, and in fact, we also had been developing a similar product. We discovered, however, that superior breathability did not always mean better comfort when hiking. Breathable often meant being cold. What’s important is the level and extent of ventilation, the optimum breathability largely depends on each hiker, the duration and intensity of the activity, what he/she does and how much he/she sweats.

Is this newer Pertex Quantum Air a better product just because it is more breathable? I welcome the higher ventilation, but it was so breathable it could get cold. In this respect, it could almost be said that the previous version was better for the fall/winter season. I wondered if there was a way to compensate for this drawback.

As I am hiking, handling hiking gear daily, I sometimes feel that the goal of all outdoor clothing and gear is how to protect and control the body heat.

Heat transfer mechanisms are mainly classified in “conduction”, “convection”, and “radiation”. When you touch something, and if you feel if it’s hot or cold, that’s because of thermal conduction. Thermal convection is the transfer of heat by air or water. The heat from the Sun or a stove is transferred by radiation. The clothes made of Pertex Alpha Direct trap air to keep you warm, so usually conduction and convection are the major factors. Additionally, I decided to improve the product by the remaining radiation; The answer was titanium coating.

When I was wearing the titanium-coated prototype, it seemed warmer than the conventional product. But to be honest, when I tried it out in the field, I was not fully sure if it was warmer or it was simply more comfortable because of the superior breathability. I was not convinced that this was the answer.

So we created another prototype that we named the “Two-Face” prototype. If you like Batman, I’m sure you will understand what I mean. The right half of the Anorak is made of different material from the left half. Through a series of actual field tests, we were able to check the differences between the conventional fabric and the new titanium-coated one.

The “Two-Face” Anorak actually taught us that the new fabric was more breathable, yet a little warmer when not moving. We also tested it on a snowy mountain ridge with wind speeds of about 10-15 meters/h and found that the wind resistance did not significantly decline compared to the previous version, even though it was more breathable. But please note that over 15 meters/h of wind can penetrate the fabric.

We like experimenting and are extremely happy to be able to deliver a better product because of it. We had fun with the “Two-Face” prototype and will probably do many more in the future.

April 2021

Editor’s Note: This article was written in 2021, when the outer fabric was switched to titanium-coated Pertex Quantum Air. Some details differ from the current 2025 version, which uses Pertex Quantum Air with updated water-repellent treatment transitioning from C6 DWR to C0 DWR. Please refer to this article as a record of the development process at that time. (Updated in 2025)