Originally Posted by
MuddyWaters
Bingo
Heating a pot is a competition between making heat and transferring to pot, and losing heat to surroundings.
You can get on order of 0.4 -0.5 fl oz alcohol for 2 cups boil with a simple setup. I do it with an open cup from small tealight , it doesnt get any simpler. No stupid priming, waiting to bloom, etc. Fill, light,.
Most alcohol stoves are just .....simplicity made difficult. Making a bunch of little flames instead of one big one...for looks, not performance.
The trick is to have tight windscreen to retain heat, optimized air intake, burner to pot distance to put hottest part of flame on pot, pot bottom area that matches flame . you want the bottom of pot covered by spread flame, but not going up sides. Wide shallow pots are far supior because they have more heating area.. But most importantly....be willing to slow down. 1/2 to 3/4 of heat is being lost to environment, make heat faster than pot absorbs it, and this innefficiency goes up.
Boiling water in 4 min vs 7 isnt worth worrying about when requires carrying extra wt. Excess air reduces the flame temperature , and reduces heat transfer. Think 3/8" gap between heat shield and pot, all way around ft or a small 2 cup pot, with air holes sized just so flame isnt rich (orange and sooty viewed in dark).
If your not willing to slow down, you need help to lose less heat to ambient...heat exchanger, pot insulation, heat shield that totally encloses pot, etc.
The best feature of caldera cone is wind resistance imo. But , just be willing to slow down a bit, use handy items to make windbreak( water bottles, foodbag, etc), and you can have efficiency for a lot less weight. My pot, stove, potstand, windscreen weigh total of .....1.9 oz. When I see people carrying 7oz caldera setups, i have to wonder ...why??? My cannister setup is only 6.8 oz, including the 3.5 oz weight of empty small cannister. But to each their own.