I've been using the same Jet-Boil for over 5 years and have never had a problem at any altitude (12.5K') or temperature (low twenties). I hear regularly that you can't trust isobutane/propane at low temps or elevation, but that's not been my experience. Can't personally speak to JB's performance at higher elevation or frigid temps, but I know people who can and swear by it.
Well, pretty much true, but if you start to dig into the details, it gets a little bit complicated. Let me see if I can be succinct while still technically accurate.
1. Isobutane/propane mixes will generally work so long as the canister temperature is
above about 20F
at sea level.
2. Subtract 2 degrees Fahrenheit for every 1,000 feet of elevation you are above sea level. In other words, at 10,000 feet above sea level, your canister stove should work down to 0F (10,000 * 2 / 1,000 = 20 and 20 - 20 = 0).
So, really, canister stoves work
better at higher altitudes,
all else being equal. Of course it can be pretty windy up high, so it's best to shelter your stove down in the nooks and crannies between rocks and such. I'll never know where these old wives tales about canister stoves not working well at altitude come from.
That said, there are hard limits on how cold you can operate a stove, and the closer you get to the temperatures I've specified above, the less well your stove is going to work. Like I say,
start warm and
keep the canister warm as you cook for best results.
As noted by another poster, with a remote canister stove (where the fuel is connected to the burner by a hose), you can go another 20 Fahrenheit lower than an upright style stove (where the burner just screws into the top of the canister), BUT you
must must must have some type of pre-heating mechanism in order for this to be safe. See my article in
Seattle Backpackers Magazine for more info.
That said, be careful. Don't take these temperature numbers as absolute guarantees. Sometimes canister mixes vary from what their label says. The numbers I'm giving you are the limits if the canister mixes are precise, but these are not "reagent grade" mixes for laboratories; these are consumer grade mixes.
Always allow a margin of safety, particularly in cold weather. But you knew that.
HJ
