Snow of Tomorrow | From hemp stalk to recyclable ski

PowderGuide:
Hey Simon, first of all thanks for your time. The first question: How did you come up with the idea of building skis out of hemp? Did you already know that it was even possible?

Simon:
The idea didn't actually come directly from us or from me, but primarily from Valentine Troi. She was in charge of the Alpenhanf 360 Grad project at the Standortagentur Tirol in November 2021. This was a platform with the aim of establishing an economic cycle for industrial hemp in Tyrol and the Alpine region - including in Italy, specifically in South Tyrol and Trentino. She now heads the GrownLab at the University of Innsbruck.
She approached us back then and asked if we would like to try out using hemp in ski construction as part of a small funding project.

Ah, okay. Was that a research project by the university or the state of Tyrol?

It was an innovation project funded by the state of Tyrol. The budget was relatively small, we built two skis, two prototypes, and they worked surprisingly well. This then led to contact with Kai and Lovis from Sachsenleinen. They produce hemp fiber tapes - so-called scrims. These are layers of fibres that lie on top and bottom of the core in the ski and stabilize it. In ski construction, there is an upper belt at the top and a lower belt at the bottom. Instead of classic woven fabrics, laid scrims are used where the fibers lie in one plane. This gives them better performance. These hemp scrims are produced in Leipzig. We carried out initial tests with them, which ultimately led to the research project we are now working on.

Was the aim from the outset to develop a ski that could be circulated?

Yes, the current research project is being funded by the FFG. This is the agency that handles funding from the Ministry of the Environment and the Ministry of Transport. Together with our consortium, we started the Kreisel project - the so-called "hemp ski", a ski that can be circulated. The idea has really grown there: a ski that is designed with the circular economy in mind. You can also find the link to our application online.

What is your specific role in the project as SPURart?

The project team consists of several partners: The University of Innsbruck is responsible for project management and carries out many measurements on a laboratory scale. Bio Composites, a company from near Stuttgart, produces bio-resins with a high bio-content based on linseed oil. Then there is Wood Kplus from Carinthia, a research institute for wood and resins. They test materials on a laboratory scale and make recommendations on how they can be processed industrially later on - for manufacturers such as Atomic. Our role as SPURart is to bring all of this from the laboratory scale - i.e. around 30 × 30 centimetres - to the ski scale. That sounds easier than it is. Not only do you have to build skis, you also have to make all the materials available in this size. That really is a big challenge.

So you are basically prototype builders?

Exactly. We work on a manufacturing scale and build prototypes. Atomic takes on the industrial scale. We prepare materials and then try to develop skis from them.

Let's move on to hemp as a raw material. Why is it particularly suitable for sustainable ski construction?

We are talking about industrial hemp here, i.e. industrially usable hemp, not marijuana. This type of hemp offers an enormous range of possible uses. You can use practically anything: the seeds for oil, the fibers for technical applications, the roots for animal feed, for example. Hemp grows extremely quickly - up to 10 cm per day. In addition, one hectare of industrial hemp stores about as much CO₂ per year as a young forest, but it grows in just 5 months. Technically speaking, hemp fibers are very resistant. In the past, it was used to make ropes for shipping. In ski construction, they have similar stiffness and elongation properties to glass fiber and are therefore well suited for composite materials.

How is the hemp stalk actually turned into a component for the ski?

Put simply, the stalk is broken open. It is soft and brittle on the inside and covered in fibers on the outside. By breaking it, the fibers can be detached from the core and pulled off. This process is very time-consuming. The fibers can then be processed into threads from which the tapes are made. That's very simplified, but that's how it works at the core.

And how does the construction of a hemp ski differ from conventional ski construction?

Basically, every ski company builds a little differently. We work using the sandwich method: All layers are placed on top of each other and pressed together. Normally, the ski consists of a wooden core that is reinforced with glass or carbon fiber at the top and bottom. In our project, the idea is to replace these fibers completely with hemp. In the long term, the core should also be made of hemp. Originally, we wanted to use waste streams from hemp fiber production, but that turned out to be very difficult. We are currently pursuing a new approach.

What were and are the biggest challenges?

We are developing products that do not yet exist in this form. You can't just take the same amount of hemp as glass fiber and hope that it will work. You first have to understand how hemp behaves: What grammages work? When does it become too heavy, when does it dampen too much, when does it have enough tension? And above all, how do you process the hemp?

Is the whole thing currently economically feasible?

Not at the moment. The cost is too high, but a research project also serves to find out. It might be possible on a manufacturing scale, but it would be much more expensive than a normal ski. On an industrial scale, it is not yet profitable or cannot be integrated into standardized processes.

You mentioned the positive properties of hemp and natural fibers, why haven't natural fibers been used in ski construction for a long time?

Flax is already being used, for example by Salomon, Atomic and others. The problem is that natural fibres are not yet as mature as glass or carbon fibres, which have been optimized over decades. They are also only available in large quantities to a limited extent. On the other hand, natural fibers are not endless fibers that always deliver the same quality, but grow naturally.

This means that the location, cultivation method, harvesting method, variety, sun/rain days, etc. have an influence on the end product, which also makes hemp fabrics very complex materials. Another challenging phenomenon is the so-called creep behavior of natural fibers. This could cause a ski to deform permanently over time. This is one of the main reasons why hemp has not yet been used on a large scale. At the same time, however, these properties ensure very good cushioning - which we will test right now during the test run.

Test ride and test experience

We, Fritz and Martin from PowderGuide, had the opportunity to test a hemp ski after the interview. It was a freeride ski with tip and tail rocker measuring 134-106-125 and a length of 183 cm. Martin is 187 cm tall and weighs 87 kilograms, Fritz is 180 cm tall and weighs 72 kg. Unfortunately, there was not enough time for the classic long-term gear review according to PowderGuide.com guidelines. Our test experience can therefore not be transferred to other conditions. The slopes were very hard and grippy. Off-piste, the terrain was rutted and bumpy. All in all, conditions that place high demands on the skis.

The ski that Simon brought us to test is a SPURart All Easy in 183 cm. It is built for tree skiing and backcountry freestyle and focuses on a wide range of applications, "easy going" and playful skiing. In this ski, the usual fiberglass layer has been largely replaced by a hemp layer, which gives the otherwise very lively ski a new character.

Grip & stability

Despite the pronounced rocker and the resulting shorter edge contact in the snow, the ski skied surprisingly well on the hard slopes, the turns could be "cut" even on icy passages and there was no noticeable and inexplicable slipping, except in very steep terrain.

The damping properties of hemp mentioned in the interview with Simon were definitely noticeable. At low speeds, the ski remains stable, but it can also reach high speeds and glides over bumps unimpressed. At higher edge angles - mind you, in the high speed range and on very uneven terrain - the radius of 18.4 meters is noticeable, which causes some nervousness. However, the ski really doesn't flutter at all and retains a full feeling at all speeds.

Cornering and radius behavior

As already mentioned, short turns were great fun due to the maneuverability. Even in large turns, the edge held so that the turn could be "closed". However, there is one characteristic of hemp skis that should be briefly mentioned here, which sets them apart from other skis and is also noticeable in their handling. Due to the high degree of damping of hemp, which Simon explained in the interview, the ski is smoother on the one hand, but less dynamic on the other.

This means that the ski has less rebound, especially at the apex of the turn and shortly afterwards, i.e. in the area where it is most heavily loaded and bent, and the skier is not "sprung" out of the turn as is the case with other skis. This lack of liveliness can be assessed subjectively, but was not noticed negatively at all in the test. In general, this characteristic is often found in freeride skis.

After all, the tamed rebound is much more forgiving of mistakes and in return requires a little more power to initiate the next turn. In our opinion, riding is not tiring as a result, but saves the sometimes energy-sapping taming of particularly aggressive skis with a lot of rebound.

Power and riding comfort

The use of hemp fiber also means that the skis have a high weight. The stance is reasonably progressive (ski center at an estimated 54-55%). The radius is medium with 18.4 meters at 183cm. The weight of the ski itself is therefore hardly noticeable, either on the ground or in the air. The hemp fibers significantly dampen the dynamics of the very reactive ash core. The characteristic - less dynamic, but well-damped - feel of the hemp ski remains manageable in terms of effort and does not require more power than other skis. Although it returns less energy, the ski's calm handling made it very comfortable to ride, especially at high speeds or on rough terrain, and it absorbed bumps with little effort.

Conclusion

This ski can not only keep up with conventional skis, but is also definitely fun. If you are generally interested in sustainable skis, you don't have to worry about riding restrictions with a hemp ski, because the damping capacity even offers advantages. We can only hope that investments will continue to be made in the development of sustainable skis in the future. If you are interested in the project and the work of SPURart, you can find more information here, and you can also visit the factory in Innsbruck-Hötting in person at any time.