In a word, no. Its true the MSR Reactor ($139; msrcorp.com) is designed to boost the cold-weather performance of its butane/propane canisters through an internal pressure regulator, which helps maintain consistent flow of gas to the burner if the canister is chilled or nearing empty. But it can do only so much. I would say the Reactor is best suited to temps into the low teens, depending on how you manage the canisters and whether youre cooking in a somewhat sheltered environment such as a tent vestibule (CO warning! Ventilate well!) or out in the open. At about 10,000 feet, the Reactor certainly will work, but it wont match the performance of a liquid-fuel stove. Keep in mind as well that the Reactor, like its competitor the Jetboil, is primarily designed to boil water, not fry up eggs on a skillet.
Does that mean the Reactor is a bad stove? Not at all. MSR has pushed the technology envelope for convenient canister-fueled stoves, creating a stove that is hot (boils a liter of water in three minutes), efficient, highly wind-resistant, compact, and light (21 ounces with 1.7-liter pot). For most outdoor camping applications, such as backpacking, mountaineering, and bike touring, its great.
Plus, there are a few tricks you can pull with canisters to boost their performance, says Drew Keegan, the stove guru at MSR. For one thing, keep the canisters in your sleeping bag at night, or warm them under a jacket during the day. That helps boost the internal pressure of the canister. You also can place the canister in some sort of shallow dish or plate, and as your melting snow in the pot warms, tip a few spoonfuls into the dish, just to the top of the silver metal band along the bottom of the canister. That too will help warm the canister and boost its output.
But for extreme conditions, very cold or at high altitudes, youre still better off with white gas. In most cases that will mean an MSR XGK EX ($149) or the Optimus Nova ($140; optimus.se). Theyre really the only reliable choice when your stove MUST work in bad weather, cold conditions, or on top of Mount Rainier.
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