I've just been doing geeky things :-) I decided to see how much gas we are likely to use, or how long a cylinder will last, during our trip down The Rhine on the tandem this summer.
I weighed the cylinder/stove combination and that came in at 260g prior to this little experiment. I then put a litre of water in the pot of the GSI Dualist we are taking and heated the water up. I then added 200g of dry pasta and cooked it until done, I reckon this will be a reasonable serving based on use at home.
I can probably reduce the volume of water boiled because of the shape of the pot, being tall and thin. When the pasta was boiled I poured off about 600mls of water so I reckon I could get away with using 750mls of water for 200g of pasta which would further reduce the gas consumption.
After the cooking phase I re-weighed the stove/cylinder combination and the result was now 244g, so the cooking experiment had consumed 16g of gas from the 97g propane/butane cylinder. I reckon taking into account drinks etc. our daily gas consumption will be something in the order of 2-3 times this but of course some days we won't be cooking at all so I'm going to work on an average value of say 2x16g of gas per day.
We'll not be using the small cartridges, I'm just using an old one up for this test, the cartridges we will take will be the 230g size. So, I reckon at about an average of 32g of gas per day a 230g cartridge should last us around 7 days, a nice round week. That's better than I had expected, I was thinking in terms of 4 days so an encouraging little experiment.
Well, it keeps me off the streets!