Mt. Whitney Portal Store & Hostel Forums General Mt. Whitney Portal Store Message Board Stoves

Scott M.

I purchased the MSR Pocket Rocket and have been able to test it using an 8 oz fuel canister. Test altitude was 6060 ft at an ambient temperature of 78 degrees. I used a 2 qt. aluminum pot that is the lower portion of the carry case for my Coleman Feather 400 white gas stove. I used normal tap water which ranges from 55 to 65 degrees here in Colorado.

I was able to boil 1 qt 13 times on the single 8 oz canister. The pot and stove was cooled between each one quart test and the canister was allowed to heat back up to the ambient temperature. Each test was a full quart(not a liter). The time to acheive a boli was also closer to 5 minutes rather than 3.5 as advertised.

I was surprised that I did not get more out of the stove but I will blame some of that on my lack of experience with it. I can get more cycles out of my Feather 400 but I am going to opt to carry the Pocket Rocket because it will save me about three quarers of a pound in pack weight and I can resupply canisters along the JMT.

As I mentioned earlier, I will attempt to test the stove at a higher altitude but it may not be until I return from my JMT trip.

"normal tap water which ranges from 55 to 65 degrees... I was able to boil 1 qt 13 times on the single 8 oz canister"

That's roughly a 40-45% efficiency. I did a similar indoor test (at sea level) and got about a 60% efficiency. But I use an aluminum windscreen that traps a fair amount of the heat.

"The time to acheive a boli was also closer to 5 minutes rather than 3.5 as advertised."

Same with me. But if you crank the stove on full to improve the boil time, the efficiency typically suffers.

EP,

After the first couple of cycles, I cranked up the stove to max. which appeared improve the results.

I am not sure how you arrived at the efficiency numbers but the advertised yield was 16 liters per 8 oz. IsoPro NSR Canister. 13 qts. calculates to 12.3 liters which is 77% of the advertised yield.

Even though the boiling point at my elevaton is approximately 200 degress farenheit, I think the reduced oxygen at this elevation has a greater impact on the burning efficiency of the IsoPro fuel which may explain the reduced yield I got.

GO WITH THE JETBOIL MY FRIEND! Everything including the fuel canister packs inside nicely.

ML, the efficiency is simply the energy that went into heating the water divided by the total energy in the fuel. If you heat 60 degree water to 200 degrees it takes 307 kJ per quart, or 4 MJ for your 13 quarts. An 8 oz can contains around 10 MJ of energy. So, 4/10 is 40%. The other 60% of the heat escapes.

I don't believe the lower oxygen pressure at 6000' is even remotely an issue. If it was you'd have to start worrying about carbon monoxide. These stoves are used successfully at very high altitudes.

That Jetboil is supposedly 80% efficient. But with such a small pot it has a limited range of uses. How could you use it to melt snow or cook up a pot of macaroni and cheese for two people?

Just got back from the northern half of the JMT and nearly replicated my results for the 4 oz. MSR Iso Pro fuel can with 7 quarts boiled before it ran out.

Scott,

Thanks, that's what I expect I will get as well and have planned appropriately.

EP,

Thanks for clarifying your calculations. One thing that may effect your numbers is you did not allow for the amount of heat it takes to convert water to steam. I suggest this because before the water comes to a roiling boil, many small steam bubbles are formed on the bottom of the pan and not all the energy in them is transferred to the surrounding fluid as they rise to the top. Having a hard time remembering my heat transfer and fluid flow studies.

I am not suggesting this would raise the efficiency significantly. I did observe in my test that I could cup my hands around the top of my pot and I never felt a lot of heat, suggesting the concentrated flame was as effeicent as it could under those circumstances. Comparing this to my Feather 400, I can't keep my hands around the top of the pot, there is a lot of heat lost.

I'm not quite sure what all this means but I am satisfied with my new purchase....I looked at the Jetboil and found it did not meet my needs and was more than I wanted to spend.

Thanks again for your comments.

ML, lost heat is lost heat, including heat lost through vaporization and convection. That pre-boil steam would cause the volume to drop slightly below 1 quart, and that would negatively affect the efficiency. But I wasn't measuring that precisely to begin with and I suspect you weren't either.

There are many possible explanations for why our results were so different. But given the informal nature of our tests it's unlikely we'll ever know.

Long thread here, but here's my 2 cents. I think butane/i***utane stoves are easy to use except in cold weather, but the cannisters are an invitation for certain people to litter(I have seen discarded cannisters at camp sites). One consideration is the heat content per gram of fuel and this is substantially more for liquid fuel than for the others and, Therefore, on a long trip you carry less weight. This is maybe hair-splitting.
I've always used liquid fuel stoves, currently a SVEA 123 w/pump. It works well with an aluminum cook-set/base-windscreen setup which used to be made by Gerry (no longer made I'm sure). If I had it to do from the start, I'd go with one of the MSR white gas stoves.
Just the 2 cents.....

Adrian

We used MSR stoves, Expedition Model which is very similar to the XGK model on Denali (cold and altitude)with excellent results. I have found that canister type stoves perform poorly
or not at all in temperatures less than zero degrees Farenheit. MSR sells a fold up aluminum windscreen that you can mold around your pot and
a fold up aluminum stove skirt that fits around
the burner (fills in void under the pot) - 2 pcs.
A must in cold weather.

"One consideration is the heat content per gram of fuel and this is substantially more for liquid fuel"

Adrian, butane and propane have greater heat content per gram of fuel than white gas and kerosene do. The difference is not huge, about 15%.

"on a long trip you carry less weight"

Canister stoves weigh less than white gas stoves, but the empty canisters weigh a little more than empty white gas fuel bottles. So on short trips a typical canister stove plus fuel weighs a little less than a typical white gas stove plus fuel whereas on a long trip the opposite is true. The break even point depends on the specific stoves, but is usually around 2-3 8oz canisters (22-33 fluid ounces of white gas).

EP,

You appear to have a very good handle on this subject. It is these differences in weight (and space considerations) that led to my decision to replace my Feather 400 with the MSR Pocket Rocket. I do ot plan on any extended trips where I will need to carry large numbers of canisters and the availability of them at resupply locations along the JMT led to my decision. In my case, I cut out over a pound from my pack.

Thanks for your earlier insights as well.