Sunday, April 16, 2017

Do Canister Gas Stoves Work at High Elevation?

There's this sort of myth running around out there that somehow operating a canister gas stove at high elevation isn't going to work very well.  Maybe, or so the story goes, you need to use white gasoline (or something) at higher elevations.  This is a persistent myth that has been passed on, hiker to hiker, for years.  I've even seen it on official Boy Scout websites.  And it's just exactly that:  A myth.

A Soto WindMaster canister gas stove running just fine at over 10,500' (3200 m) in the Sierra Nevada in California.
Origins of the Myth
The myth got its start back in the early 1970's when canister gas stoves started seeing more wide spread use.  The fuel used back then was 100% n-butane.  N-butane is a lousy fuel for cold weather.  Backpackers at high elevations encountered something that caused their canister gas stoves to work poorly:  Cold.  And thus the myth was born. The myth is kind of fact based.  Kind of.  I mean gas stoves were genuinely not working well at high elevation – but the elevation itself was not the problem.  The problem was actually the cold, and the problem would have been just as bad or worse at sea level.  Thus, a misinterpretation of real events lead to the myth.  The real problem was cold, but people wrongly concluded that high elevation was to blame.

Modern Canisters
Now, you may be thinking:  "Hikin' Jim, you big dummy, who cares why?  It's still cold to this day at high elevation today, so my canister stove still isn't going to work."

Ah!  Not so fast.  Take a look at a modern backpacking canister.  Typically printed on the side or top you'll see something about propane and isobutane in addition to "butane" (n-butane).  Yes, back in the 1970's they only had n-butane in canisters.  Now, they include propane and frequently isobutane, gasses that both have much better cold weather performance than n-butane alone.

A modern backpacking canister.
Note that it contains not just plain butane (n-butane) but also isobutane and propane.
When multiple gasses are mixed together, they form a blend that has far better cold weather performance.  You still need to consider cold weather, but it's no where near the issue that it once was – and cold weather can impact a gas stove irrespective of elevation.

 Vaporization (Boiling) Point
n-butane    -0.5°C    31°F
isobutane    -12°C    11°F
propane      -42°C   -44°F
The vaporization points of the three gasses commonly used in canister gas.
The vaporization point of a gas blend lies somewhere in between the boiling points of the constituent gasses.

If you are expecting cold weather, which brand of canister gas is the best to use?   See:  What's the best brand of gas for cold weather?

A canister gas stove running just fine at moderately high elevation, about 7200'/2200 m above sea level
Stove Considerations at High Elevation
There are still things to consider when using a stove at high elevation, but these considerations apply to all stoves not just canister gas stoves.

The boiling point of water.  As you climb, the boiling point of water decreases by almost 2 degrees Fahrenheit per 1000' of elevation gained (about 1 degree Celsius per 300 m).  At sea level, water boils at 212 Fahrenheit/100 Celsius.  At 10,000'/3300 m, the boiling point of water is 193 Fahrenheit/90 Celsius.  Since the boiling point is lower, all else being equal, water boils faster at higher elevations.

Cooking time.  Since the temperature of boiling water is lower at high elevation, it generally takes longer to cook something.  Note that this doesn't really apply to frying etc. but only to those types of cooking that involve boiling water.

So, while it's faster to boil water at higher elevations, generally cooking takes longer, and you therefore may need more fuel when you cook at higher elevations.  You can offset the need for more fuel by things like "cozy" cooking where you put your food in something insulative so the food will continue to cook even after you're done using your stove.  You should also learn the Tips and Tricks of Good Stove Fuel Economy.

Piezoelectric ignitions.  Piezo based ignition systems often struggle on hand held butane type lighters as low as 5,000'/1500 m elevation.  Piezoelectric ignitions tend to work better on stoves than on lighters, but above 10,000'/3000 m elevation, one may still encounter problems.  You should always bring alternative means to light a stove at any elevation, but it's even more important at elevations above 10,000'/3000 m.  Some common alternative means of ignition include:
  • A non-piezoelectric butane lighter.  In other words, a common flint wheel type lighter such as a Bic brand lighter.
  • Matches.
  • A fire steel (ferro rod).
An MSR Reactor operating just fine at over 23,000'/7000 m elevation on Muztagh Ata (24636'/7509 m) in China.
Photo credit:  Reuben Brimfield.  Used by permission.

The "Proof of the Pudding"
If somehow you're not yet convinced that canister stoves not working at elevation is a myth, don't believe me; believe the mountaineers.  What are more and more world class mountaineers using?  Canister gas stoves.  Note in the above photo that a canister gas stove is being used at over twenty three thousand feet in elevation.  That's over 7,000 meters above sea level.  This is far higher than most of us will ever climb.  Mountaineers know their business.  Mistakes in high elevation mountaineering are frequently fatal.  Why do mountaineers use canister gas stoves?  Because they work.  Use by mountaineers tells us all we need to know about the myth of poor performance by canister stoves at high elevation.  It's just that, a myth.

Thanks for joining me as I engage in a bit of "myth busting."

Happy stoving,


No comments:

Post a Comment