I definitely dont get how the water works…
Well, think about it for a second. In order for your gas stove to work, you’ve got to have gas coming out of the canister. In order to have gas, the canister has to be a certain temperature. If it’s cold out, your canister might not be able to deliver enough pressure to properly run a stove.
Now let’s say you’ve got a isobutane/propane mix in your canister (for example, MSR, Snow Peak, JetBoil, or Brunton). What’s the boiling point of the fuel inside that canister? Well since isobutane alone boils (turns to gas) at 11F, your fuel boils at at least that temperature (and probably colder depending on how much propane is in your mix). What’s the temperature of (liquid) water? Well, it can’t drop below 32F/0C or it’ll turn to ice. In other words, liquid water is a least 20F/10C warmer than the boiling point of your fuel. So long as your fuel is immersed in water, then you’ll have plenty of operating pressure.
How much water we talking about? I dont carry anything to put water in that could also hold the circumference of the canister. (just my cookpot- which OBV will be on the stove!)
Well, it depends. If it’s really cold, more water is better since more water will take longer to freeze. Generally though, submerging the canister up to about 3/4 depth is plenty. You could put the canister and water into a ziploc bag or similar if you want a UL solution.
HJ
Adventures In Stoving