[pct-l] stove burn time

[Timothy Nye]

Something to bear in mind with the rate of fuel usage with canister stoves
is the temperature of the water that you're heating.  This is true of all
stoves, but is trickier with canisters as you can't see the fuel level.
There are spec sheets that purport to show how long it takes to bring water
to a boil, however they typically assume a constant water temperature that
may well be unrealistic.

In order to truly get an idea of what I may be dealing with in adverse
conditions, I like to heat a pint of ice water (sans the ice) in order to
get a worse case analysis of the life expectancy of cartridge.  I'm at
slightly above sea level, so I think this works fairly well; at higher
elevations the lower barometric pressure allows boiling at a lower
temperature, obviously.

I've been working out the amount of water a Esbit tablet can boil under
various conditions.  Of course, I'm aided there by the ability to use a
highly reflective foil wind screen with them.

In sum it seems that there should be a correlation where an offset,
or constant, can be achieved in the burn time between the lowered
temperature required to boil at altitude and the lower potential temperature
of water sources likely to be encountered at elevation.