In reply to A Reid:
The Jetboil website states that a 100g canister can boil 12ltrs of water (for the Flash but look up your system). So I'd work off of this:
For example, 3-4ltrs of drinking water & hot drinks + 0.5ltrs for breakfast + 0.5ltrs for dinner. So 4-5ltrs per person, per day.
For the sake of things 4ltrs per day = 3 days per 100g canister (going by the above), 3 weeks (21 days?) So 21รท3 = 7x100g canisters per person.
But also bear in mind (as I assume you're aware of) that as the canister gets used up, the longer the boil time so the more gas you use. So possibly use a newer canister to bring to the boil, and a half empty/used canister for simmering. And also, like you suggested, I'm not sure what the quality of gas is like in Kyrgyzstan so it could be more so consider getting more rather than have the bear minimum I.e. 10 canisters instead of 7 per person.
This all works in theory and I haven't tried and tested this, but this is what I've done to calculate how much gas I'll need for a trip to Denali that I have in planning.
Post edited at 23:13