Companion forum thread to:

The Effect of Cold on Gas Canisters

good article Roger

If you look at figures 3 and 4, towards the end of the life of the canister, the blue and yellow are both good - any n butane is not good for cold weather, iso butane is much better

This is the same as my experience, isobutane is good down to maybe 20 F (or maybe 22 F).

I have been buying Snowpeak "Giga Power" at REI that is a propane/isobutane mixture that has worked good.

Actually, putting in any propane is unnecesary. It helps early in the life of a canister, but towards then end of the life of the canister it makes no difference.

Excellent article. This will be very helpful.

Great job! This is the stuff that keeps me here.

Effin genius .... This should put all cold weather stove arguments to rest

the SP Gold lists 85% Iso-butane, not N-butane

http://www.snowpeak.com/gigapower-fuel-250-gold-gp-250g.html

maybe their old red can stuff had N-butane in it??????

c'mon, not one fart joke? is this not the same backpacking light that published the arm sluice no TP method?

... since thermodynamics class 30 years ago. Now when I'm on a mountain trail, boiling water on my Snow Peak, trying to keep my can (canister?) warm, I'll think fugacity!

Great Article, thank you.

If anyone has any data on other brand fuel mixes to add for reference, this may be a good place:

[Key]
Brand: Propane / Isobutane / N-butane (country) net/gross weight

Jetboil ?? / ?? / ?? (Korea) 230g/356g
Brunton: 30 / 70 / 0 (Korea) 225g/355g
Optimus: 30 / ?? / ?? (???) ???g/???g
Max Burton: 20 / 60+ / <20 (Korea) 230g/???g
Campinggaz 20 / ?? / ?? (France) 230g/???g

Fascinating article. I'm much further up the learning curve after reading it. Will read it multiple times. Thanks for the spreadsheet.

You add tremendous value to BPL!

Every good article has a summary or conclusion section.....for those who don't speak chemistry but want a quick 3 sentence explanation!

> maybe their old red can stuff had N-butane in it??????
I think that is the case.
Obviously, they have seen the light.

Cheers

> a quick 3 sentence explanation!
Unfortunately, seriously technical things are not that simple.

However, try the paragraph after Figure 4 for a summary, and also the whole section after that for another recommendation.

cheers

Roger, can the expansion/boiling at the valve cause the canister temperature to plunge (I have seen mine freeze) taking the actual temperature of the canister well below the ambient temperature? Could this take most canisters (regardless of percentages of each gas) into the no flow zone at -20 degrees C, even when air temperatures are around zero C?

I just sleep with a quart of water (which starts out just below boiling and dwindles to warm by morning) and then use a bit of it in the morning in a 1.5 inch deep bottom of a gallon milk jug (which I use as wash basin, water dipper, and bowl. I set the canister in the water with the stove attached and the gas flows great in freezing temps.

You said ambient air temperature drops about 6.5C per 1000m in elevation gain (per FAA).

that's equivalent to 3.6F per 1000 feet. That sounds about right (if a little high); but doesn't your original height make a difference. E.g. going from 0 to 1000ft versus 11,000 to 12,000ft?

---
edited per comment below. Thanks.

Edited by kevingoulding on 11/03/2010 12:28:54 MDT.

Actually, I think that 6.5*C/km gained is equivalent to about 4*F/1000ft.

David - yes, the boiling of the liquid gas will cool the canister below the ambient temp. This is explicitly mentioned in the article. This effect gets worse as the canister empties when there is less mass from which to extract heat. At 0C, the cooling effect will be small when the canister is full but will be enough to stop the flow as the canister nears empty for a P/B mixture. P/iso-B may be ok.

> a quick 3 sentence explanation!
Unfortunately, seriously technical things are not that simple.

True that it's not that simple. And I appreciate Roger's and Stuart's explanation of the details. And I've never been accused of being brief. But let me try:

1. Stop reading if you will be cooking at temps confortably above 0C (32F) (any fuel will be OK) or below about -40C (which is also -40F) (this article offers no help for that case).


2. For temps between -40C (-40F) and -25C (-13F) use 100% propane and accept a substantial weight penalty.


3. For temps above -25C (-13F) you can use any of the mixtures that contain both propane and iso-butane with a stove designed to burn canister fuel fed to it as liquid (connected to an inverted canister). Kovea's mix will work down to about -30C with this setup.


4. For temps between -10C (+14F) and 0C (32F) you could use MSR IsoPro red canister fuel or Kovea white canister fuel (propane/iso-butane mixtures) with an upright canister.


5. Because of evaporative cooling the above suggestions fail if you want to operate the stove for very long in ambient temps near the colder end of the temp ranges. For that case, switch to a setup that handles colder temps or set the fuel canister in a bowl of cool liquid water (at the cost of increased fiddle-factor). This will also extend the temp range of the upright Propane/iso-butane mixtures a few degrees C when the canister is nearing empty.

Edited by jcolten on 10/27/2010 14:41:40 MDT.

Interesting to note that "back in the day", high altitude Himalayan expeditions favored the old Gaz 206 Bluet stoves. These worked fine in this situation because in spite of the cold (well below freezing) the MUCH increased altitude (lower atmospheric pressure) effectively increased the pressure inside the cannister to the point where the butane would still effectively vaporize.