We developed Winter Gas to increase the performance of gas stoves at lower temperatures. Low temperatures reduce the pressure in the gas tank and worsen the evaporation of the liquid gas. This causes the stove to burn with less power or not at all, even though there may be gas left in the container. The main innovation behind the improved cold weather performance of Primus Winter Gas is VaporMesh. VaporMesh is a highly absorbent paper that sits around the entire inside of the container, thus increasing the surface area from which the liquid fuel evaporates to gaseous form. This helps keep the pressure higher which makes the stove burn better. The widened surface area also speeds up the liquid to gas transformation process, and it is this rapid transformation that determines the pressure inside the container. Fast process = high pressure.
Compared to conventional gas containers, this is what gives Winter Gas its reliable performance, even in cold conditions where it was previously impossible to use gas.
This is how Winter Gas maintains a smoother performance.
1. Expanded surface area = increased pressure
The phase transition takes place from both paper and surface instead of only the surface of the container as with a conventional gas container. In this way, the surface area is expanded without requiring a larger container. This increases the pressure in the gas tank.
2. Reduced boiling time
The VaporMesh paper and gas mixture increases the speed of the phase transition from liquid to gas. The burner receives more fuel, which means that the cooking time in really low temperatures will be shorter compared to other gas containers.
A type of paper that coats the inside of the container and absorbs the gas in its liquid form. The effect of the VaporMesh paper intensifies as the fuel level decreases, and the gas gets a smoother performance over the lifespan of the gas tank.
4. Liquid gas
The mixture of propane and isobutane gas is the same as that of Power Gas: around 20% propane and 80% isobutane.
When comparing two completely new and full gas tanks (Power Gas and Winter Gas), the difference is not noticeable at first as the pressure is high in both containers, but as more gas is consumed from the containers, the difference becomes more obvious. When gas containers without VaporMesh are used in cold conditions, the pressure in the container decreases due to the cold, which means that the stove burns with less power or not at all. This becomes more obvious when the container is no longer full. After 60 minutes of cooking, Primus Winter Gas is about 9% more powerful than a gas container without VaporMesh. After 120 minutes of use, it delivers around 15% more power.
Take a look at the table from a comparison test between a full container of Power Gas and a full container of Winter Gas, carried out in a freezer room with a constant temperature of -20 °C. Both gas containers were left in a freezer for 48 hours before the test was performed to better reflect a real-world situation when you are out for several days. The test used two Primus Spider Stoves and an infrared thermometer with laser pointer.
To check whether the power of Winter Gas was sufficient to cook, we boiled half a litre of water at the end of the test, which went well without any noticeable differences from normal temperatures.
The year that Winter Gas was launched, it won the Outdoor Industry Award GOLD MEDAL at the 2014 Outdoor Trade Show for demonstrating innovation and drive in the area of combustion and heating. The award is considered one of the most prestigious worldwide - with only seven gold winners in total in 2014. The gas also won in the categories of “Camping Equipment” and “Product of the Year” at the Outdoor Trade Show 2014. The Outdoor Trade Show is the UK's largest outdoor fair. In 2015, Winter Gas won another prize: “Editors’ Choice” of the German newspaper Outdoor.