For 2016, Primus is bringing Winter Gas to the US–a new blend optimized to deliver reliable performance in the coldest conditions. With the introduction of Winter Gas, Primus moves away from offering one blend for all purposes but instead now offers different blends meeting specific use cases.
Everybody who has used a gas cartridge stove in cold conditions knows this: the lower the temperature, the poorer the performance of the stove. In cold conditions, the cartridge pressure decreases under use making the stove run with less power or not at all–even though the cartridge might have plenty of fuel left in it. Why? Liquefied gas doesn’t evaporate properly the colder it gets.
To get around this problem, you could buy an inverted canister stove, but that’s a bit of a pain for the few times you go out in winter. Instead, Primus Winter Gas lets you take your upright gas stoves like the Jetboil MiniMo or MSR Windboiler on your winter outdoor adventures.
Primus Winter Gas is an adapted fuel blend that improves performance in cold conditions down to -22°C (-7°F). This new blend of propane and isobutane features an innovative technology inside the cartridge called Vapor Mesh.
Vapor Mesh is a highly absorbent paper that will keep the pressure higher making the stove run better. The VaporMesh increases the surface on which the liquid fuel can evaporate into gas state. The increased surface makes the change from liquid to gas faster and the speed of this process is what determines the pressure inside the cartridge. Compared to conventional cartridges, this makes it work in conditions when it was previously hard to use gas fuels.
When comparing two totally new, full cartridges (one regular and one Winter Gas), the difference is not very notable since the pressure is high in both. But as the fuel inside the cartridge is consumed, the difference becomes more and more evident. With “normal” cartridges in cold conditions, the canister pressure decreases under use, making the stove run with less power or not at all. This is obvious when using a cartridge that is not full. After 60 minutes of cooking, a Winter Gas cartridge is approximately 9 percent more powerful than one without Vapor Mesh and after 120 minutes of cooking it delivers about 18 percent more power.
Expect Primus Winter Gas to retail for around $8 for a 230-gram or 8-ounce canister.