Jetboil In Frigid Temps At Altitude - The Pros Do It (?)

[DayTrip]

I'm not sure which of several Winter threads I discussed this in so I thought I'd just split it out into a new thread/question. I'm home enjoying all the shoveling and bronchitis so I've been binge watching a variety of mountaineering documentaries. The last three I have watched (the most recent being Meru with Conrad Anker and Jimmy Chin) had a lot of shots inside their portaledge where they are distinctly using a Jetboil stove for all their needs (looks just like the Sumo model I have). It has no insuation wrapped around the gas can, no water bath, etc. It's just hanging there melting snow, heating food, etc. So what are they doing to get it to work?

Most of the prior feedback I got was that the stove doesn't perform well in the cold without a lot of tinkering and when it is very cold just forget using it and based on some of my experimentation earlier this Winter it is slow. So what are they doing that makes it work fine just hanging there and makes them willing to rely on it when the stakes are high? Are there different fuel canisters available overseas with a different gas mix? That was about the only thing I saw that was different. Their fuel cans were white not the usual gray and I think he referred to it as "propane" in one clip.

Was puzzled to see this in several films when it seemed like the consensus here on VFTT is that the stove is garbage when it's cold. ??

 

[sierra]

They probably heat the canister ahead of time.

 

[nartreb]

It' not garbage when it's cold. I haven't done any winter camping in a few years, but in the past my JetBoil worked fine at any temperature I was willing to camp in (i.e., down to single digits below zero Fahrenheit) with no coddling of any kind. Of course I would not be surprised if the guys in those films are keeping their canisters in their jackets and sleeping bags to ensure there's no problems even when it's much colder than that.

 

[DougPaul]

Your title likely has the key word--altitude. Butane canister stoves can work to lower temps at altitude due to the lower ambient pressure. (Nothing in the NE US qualifies...)

Some canisters contain a mixture of propane and butane, but pure propane has too high a vapor pressure at "normal" temps for standard canisters. (They would explode. Compare to the heavier steel bottles on the propane tanks at a hardware store.)

My guess is that Chin and Anker (well-known high-altitude mountaineers) were using a propane-butane mixture fuel at altitude.

BTW, inverted fuel canisters work better in the cold than upright canisters. A quick check suggests that Jetboil stoves use upright canisters.


There used to be (ca. 1973) a pure propane backpacking stove (the Primus Grasshopper), but it used heavy hardware store hand-torch propane tanks. A search suggests that there are more recent versions that use smaller (but still heavy) propane tanks. There are certainly propane car-camping stoves.

Doug

 

[peakbagger]

Having spent a few cold trips on the AT in early spring and late fall with a pocket rocket and MSR red fuel tanks, I learned how to work around the limitations but they were there and varied with the amount of fuel left in the tank. A full tank had far fewer issues while a near empty tank started having issues at higher temperatures. If it was below 30 degrees and I hadn't warmed up the tank I could get a flame but it wouldn't crank up. Not bad for simmering but not so good when wanting to boiler water. I could cup my bare hands around the tank and could hear the flame increase notably. I have a heat shield I use and expect there is some minimal contribution from radiant heat from the burner warming the top of the tank. MSR red cans of fuel are propane butane blend. The claim is that at cold temps the lighter fractions of the gas vaporize more readily preferentially going to the burner leaving harder to volatilize fractions in the canister so that as the tank level goes down the level of hard to vaporize fractions increases. I expect most weekend warriors start up with fresh canister so the issue with near empty ones is far less important. I was getting 14 days off a canister and therefore I was squeezing every bit of butane I could get out of a canister.

I have seen and heard of people who make homemade heat transfer devices to warm the tank with heat from the burner, I expect they can work as I used to have one for an ancient primus butane stove but it was nothing that I expect could be made safe from product liability.

Its interesting Doug mentioned a Primus Grasshopper, I looked up one on the web and my ancient Primus stove is identical to a Grasshopper except that it is equipped with a connection for butane canisters. Unfortunately the canister used is a different dimension than the current canisters so it no longer is of any use. Considering its 40 year old I expect obsolescence should be expected.

 

[jfb]

my ancient Primus stove is identical to a Grasshopper except that it is equipped with a connection for butane canisters.

I had one of each, and they were both way better than cooking on a wood fire.

 

[iAmKrzys]

Some of the gas canisters made by Primus are light gray in color and may appear as white - google for it to see. Primus also makes "winter gas": https://primus.us/products/winter-gas-230-g-5?variant=17262656901 that is supposed to be better in low temperatures, but I don't know if it is compatible with JetBoil. I have never used it.

 

[DougPaul]

Some of the gas canisters made by Primus are light gray in color and may appear as white - google for it to see. Primus also makes "winter gas": https://primus.us/products/winter-gas-230-g-5?variant=17262656901 that is supposed to be better in low temperatures, but I don't know if it is compatible with JetBoil. I have never used it.

The description of these canisters emphasizes an internal structure to increase the surface area for evaporation, but says nothing about the composition of the fuel.


The following discussion is restricted to upright canisters where the evaporation occurs inside the canister.

In an upright canister, the vapor pressure of the fuel must be greater than the ambient atmospheric pressure (nominally 760 mm of mercury at sea level) for gas to leave the canister and enter the burner. (The vapor pressure of the fuel is a function of its composition and the temperature.) As the fuel evaporates, it cools the remaining liquid and the stove will go out if it cools to the point where the vapor pressure is no longer sufficient to force gas into the burner. (Thus a heat flow into the canister is required to keep the stove going--if the canister were perfectly insulated, it would go out after a while.)

A bit of research shows three fuels to be used in stove canisters: n-butane, isobutane, and propane. The better canisters seem to be mixtures of isobutane and propane (MSR ISOPRO is 80% isobutane and 20% propane).

Characteristics of the three fuels:

                boiling pt at           
                .5 atm   1 atm          VP @ 20C        VP @ 100C
                ------  ------          --------        ---------
n-butane        -16C     -0.5C          2.1 atm         14 atm
isobutane       -28C    -11.7C          2.9 atm         18 atm
propane         -56C    -42.1C          7.9 atm         42 atm

.5atm ~ 5500m altitude
1 atm = 760 mm mercury
VP = vapor pressure

The boiling points for each altitude are the minimum fuel temps at which the stove can operate. The vapor pressures for 20C are to give an idea of how well the fuel will work at room temp and the vapor pressures at 100C are to give an idea of how strong the canister must be to prevent an explosion. A mixture fuel will have characteristics intermediate of the component fuels.

Mixture fuels have the disadvantage that the higher vapor-pressure component will evaporate faster than the lower vapor-pressure component so the composition of the fuel will change toward the lowest vapor-pressure fuel as it is used.


Inverted canisters have two advantages:
1. The fuel is passed to the burner as a liquid and evaporation does not cool the canister.
2. The composition of the fuel does not change as it is used.
(The vapor pressure inside the canister must still be greater than ambient for the stove to operate so the boiling point limits still apply.)

Doug

 

[hikerbrian]

Without actually seeing the clips and knowing what conditions were (specifically, what temp the stoves were operating at), I'm going to guess the temperature inside their portaledge was relatively high. A friend of mine had a Jetboil he'd fashioned into a hanging stove, and we used it at 10k' on Shasta in late winter, with ambient temps around 10 degrees F. The heat of the Jetboil warmed the inside of the tent to, I don't know, 40 degrees at least. On the other hand, a year earlier, before he'd fashioned the hanging stove, we tried to use the same Jetboil at the same altitude in slightly warmer conditions (maybe 20 degrees F), and we could not get reasonable output. In that case, the stove was sitting outside the tent, and so 20 degrees F was the starting point of the canister.

Although the hanging stove largely solved the inefficiency problem of the canister being at low temp, I found the use of it to be an extreme hassle. It's a little scary to have a ball of flame in the middle of your tent with flammable materials that your life depend on scattered all about. Furthermore, we had to shut off the stove every few minutes to empty the water into a Nalgene, then refill it with snow, then get it started again. Without spilling any water anywhere, and without touching the hot surfaces to any of the abundant nylon and down. Major PITA.

Now, I'm not Conrad Anker or Ed Viesturs or any kind of hard man at all. Real mountaineers deal with this kind of hassle because, well, they're hard men. And also because that hassle is the least bad option of those available.

 

[peakbagger]

To totally geek out on this there is also the Joule-Thomson effect (gases get cold when they expand) impacting performance. Gas from the canister is expanding when it exits the burner which causes the gas and the surrounding jet to cool down. If there is any moisture in the area it can cause any vapor in the air to freeze and nearly plug the burner.

One day on a -15 F day, I had a large pot on a whisperlight that was dug down in hole to shelter it from the wind. The pot bottom was quite large and even with the foil reflector with the stove at wide open there was enough heat reflecting off the pot to heat the surrounding snow which caused some water vapor to form around the stove burner. Those familiar with whisperlights will remember that the jet is separated from the burner by an air gap. When the white gas expanded as it left the jet it cooled down and that was enough to freeze the jet. It didn't freeze completely but did form a little ring of ice limiting the stove output to a very low flame. Took me a bit of head scratching to figure out what was going on. Once I figured it out I moved it up so it had some air circulation and it was fine.

I expect hanging a pot from tent ridge is going to create better air circulation and also will keep the stove in slightly warmer microclimate than outside on the snow in a vestibule.

 

[DougPaul]

To totally geek out on this there is also the Joule-Thomson effect (gases get cold when they expand) impacting performance. Gas from the canister is expanding when it exits the burner which causes the gas and the surrounding jet to cool down. If there is any moisture in the area it can cause any vapor in the air to freeze and nearly plug the burner.

Evaporative cooling plus the expansion cooling is a double whammy... (However, expansion cooling is reduced at lower temps due to the reduced vapor pressure of the fuel.)

And, of course, the temp of both the liquid and gaseous fuel in the canister can be below the freezing point of water even before these cooling processes can take effect.


It is possible to modify a canister stove to leak heat from the burner to the canister to improve low temp performance. However this is a rather dangerous practice as it can cause the canister to overheat and explode.

Doug

 

[DayTrip]

Without actually seeing the clips and knowing what conditions were (specifically, what temp the stoves were operating at), I'm going to guess the temperature inside their portaledge was relatively high.

They were all sitting in sleeping bags with coats and hoods on so I didn't consider it may have been warmer than outside. Supposed that could have been case. The only thin I noticed for sure that was different was the white canister (mine are dark gray) so I didn't know if there was a different fuel mix available for cold weather that was Jetboil compatible (and if so why they wouldn't offer it on their site). I know based on my initial experiments awhile back as you start to drop below 30 deg or so you have to start doing some or all of the tricks you had mentioned to me in other thread for reasonable performance. When I saw their Jetboil just hanging their working like a charm I was like "Hey! What's up with that?".

 

[DayTrip]

It is possible to modify a canister stove to leak heat from the burner to the canister to improve low temp performance. However this is a rather dangerous practice as it can cause the canister to overheat and explode.

Doug

Mark Twight's book covers this and he also mentions it is super dangerous, but not all that uncommon. I will NOT be adding this to my bag of tricks.

 

[alexmtn]

It' not garbage when it's cold. I haven't done any winter camping in a few years, but in the past my JetBoil worked fine at any temperature I was willing to camp in (i.e., down to single digits below zero Fahrenheit) with no coddling of any kind. Of course I would not be surprised if the guys in those films are keeping their canisters in their jackets and sleeping bags to ensure there's no problems even when it's much colder than that.

Per my comments in the other threads on this subject, I've experimented extensively with my Reactor, which runs on the MSR fuel that Doug described. At somewhere around 10 degrees F and below (my travels have taken me to minus 10), and absent supplementary warming of the canister (most commonly by liquid water), the stove burns the propane portion of the fuel just fine. This accounts for ~15 minutes of the expected 80 minutes of runtime -- and at that point, it wimped until re-warmed.

Alex

 

[DougPaul]

To totally geek out on this there is also the Joule-Thomson effect (gases get cold when they expand) impacting performance. Gas from the canister is expanding when it exits the burner which causes the gas and the surrounding jet to cool down. If there is any moisture in the area it can cause any vapor in the air to freeze and nearly plug the burner.

Evaporative cooling plus the expansion cooling is a double whammy... (However, expansion cooling is reduced at lower temps due to the reduced vapor pressure of the fuel.)

I thought about this a bit more. (Had to think about something while shoveling... ) The expansion temperature drop occurs in the control valve (where the pressure drop occurs) and would have little if any effect on the fuel temp in the canister but will cool the downstream plumbing possibly resulting in frost as noted by peakbagger.

Doug

 

[peakbagger]

I agree, unless there is enough moisture in the air to cause icing at the nozzle, the cooling due to expansion as it leaves the nozzle shouldn't be an issue unless its in an area with high relative humidity where the cold nozzle surface could cause ice to form Not being familiar with jet boil I don't know if there is enough air gap that this could be occurring out of sight of the user.

 

[jniehof]

TThe only thin I noticed for sure that was different was the white canister (mine are dark gray) so I didn't know if there was a different fuel mix available for cold weather that was Jetboil compatible (and if so why they wouldn't offer it on their site).

Snowpeak's canisters are white with red lettering. My MSR fuel is labeled "four season mix" and I think the Snowpeak's I've picked up have been the same, but I don't think they offer a three season mix, so it's probably just marketing for having the propane component.

 

[dave.m]

To my mind, this discussion underscores the importance of practice and familiarity with one's stove in real, localized conditions. All stoves and fuels have quirks and IMO the key is to have enough experience that these quirks become routine and boring.

My winter stoves remain the Svea 123, Trangia or Emberlit, depending on the trip and Party size. For the Svea and Trangia, I pack small disks of thin plywood to serve as an insulating base.

I've long ago moved to floorless tents which allow you to cook in the floor and experiment with CO poisoning . My preference is in the doorway with the door open, while laying in my bag. Never with the door closed.

Couldn't pay me to carry an MSR white gas stove. I know I've mentioned it before, but I've twice, not once but twice, hauled MSRs out of Crag in full melt down. Leaky plastic pumps catch fire and game over.

Anyway... the best advice on stoves is to keep them handy between trips and to make coffee or tea on them once a week all year round. Learn the stove, whatever it is.

 

[DayTrip]

Snowpeak's canisters are white with red lettering. My MSR fuel is labeled "four season mix" and I think the Snowpeak's I've picked up have been the same, but I don't think they offer a three season mix, so it's probably just marketing for having the propane component.

Are MSR/Jetboil fuel canisters interchangeable?

 

[DayTrip]

I found this on their website about using in the cold: http://www.jetboil.com/Support/FAQ/Does-Jetboil-Work-in-Cold-Weather/

So I guess the guys in the portaledge probably just warmed the canister before use and/or the temp inside as mentioned was probably much higher than I assumed. No different fuel mix or magical expert hack (which is a good thing because I like the idiot proof operation of the Jetboil). If people are willing to take it on Everest I have to assume warming the canisters allows for reliable operation and reasonable performance even in pretty cold weather so it should certainly be fine for anything I'd ever do. I guess I'll have to retry some tests at the lower temps to see how much the heated canister improves performance. I had a chance to test much below 20 deg F, which according to the website it should perform in normally.