ISOPRO Cannisters

Does the % of Isobutane and Propane make that much difference, in any, to stove performance? Is there a blend that would work better at lower temperatures, or at higher temperatures? Would one be better than the other at sea level or higher elevations? Does the difference in BTU's of butane (102,032/gallon) and propane (91,600/gallon) have any impact on stove perforrmance? Anybody have a manufacturer preference or one to be avioded?

MSR - 80% Isobutane, 20% Propane
Optimus, Brunton - 70% Isobutane, 30% Propane

Thanks, Rick

Hi Rick,

When in doubt, go for the most propane you can get. Propane has a much higher vapor pressure than iso or straight butane and thus, will work better in cold weather.

Also note that in cold weather with a typical vapor feed stove the propane will burn off first, leaving mostly iso behind. The result is diminishing performance and likely the need to warm the fuel to make it burn. This is why liquid feed stoves work so much better in winter.

Cheers,

Rick

All the info you want here
http://www.bushwalking.org.au/FAQ/FAQ_Efficiency.htm
Basically at 32f and above butane works just as well as any gas mix and generally is cheaper.
Propane has the lowest boiling point (-42c/-43.5f) so the higher the propane content the better it will work below zero.
Isobutane works down to -12c/10f
At altitude the boiling point of butane is lowered, so the higher you go the lower the temperature can be, for example down to 2f at 20,000f.
However of course at 20,000' 2f could also be your max day temperature....

http://books.google.com.au/books?id=3hgJ...lt&resnum=4
Franco

I've not noticed a huge difference between the brands you mention rick. and they all kinda suck and are sluggish in a conventional canister stove if it's much below freezing.