Monday, February 6, 2012

Testing a Penny Stove in the Cold

I am a big fan of DIY alcohol stoves, especially the penny stove variety. I like DIYing in general, and in this case it's also about the fact that a homemade penny stove is actually better than many if not most of the commercial offerings in terms of weight and heat output.
Heineken Penny Stove and stand

In a recent thread on the German Radreise-Forum about equipment choices for an overland trip from Germany to China, the question of the ideal stove came up. Alcohol stoves were discounted by some, based on the availability of fuel in many countries along the way and due to their questionable performance at high altitudes and low temperatures. I was somewhat surprised by the latter objections, as on the penny stove website there are a number of testimonial about the cold weather performance of the stove, including a quotation by Reinhold Messner who supposedly made tea with a jet-based alcohol stove on one of his expeditions to the Himalayas. However, the information there was not very specific -- how much longer does it take to boil water at cold temperatures and how much more fuel does it take -- and my curiosity was sparked. I decided to test it myself.

Air temperature of -9°C
Stove, pot, windscreen
This winter has been pretty mild in Montreal and so it took some time until it was cold enough for a meaningful test. Last Sunday morning had been predicted to be about -10°C and so I put my stove, fuel, and thermometer out on the porch right after waking up and ran the test after about an hour. So this is the experimental setup:

Altitude: 10m
Amount of water: 1l
Air temperature: -9°C
Water temperature at start: 5°C
Pot: 2.2l REI coated aluminium pot with slightly to big stainless steel lid (I couldn't find the original plastic lid)
Stove: Heineken-based penny stove with wind screen
Wind: almost no wind
Fuel temperature: same as air temperature

Burner at full power
I started the timer right before lighting the stove. The lighting itself was unproblematic: I just dropped a burning match into the stove. The total time until reaching a full boil was about 14 minutes and 30 seconds. I didn't measure the fuel consumption, as my kitchen scale recently broke, but the stove still had quite a bit of fuel in it.

5°C water right from the tap

Now what's the bottom line? Is the penny stove an appropriate choice for winter camping or riding through the Himalayas? I don't think you can definitely answer that question based on my test. Unfortunately, I don't own any other types of stoves and therefore couldn't do replications of the test on other equipment. But there are some hints: first of all, the stove does work in the cold. Even if it may not be the fastest, it will still boil your water in a not totally unreasonable amount of time. Second, we can compare the stove's cold weather performance with some of the published data at higher temperatures: in this test, a penny stove boiled 32 oz (0.95 l) of water in 7:50 at 20° degree air temp with 18°C degree water temp and 670m elevation. It would be interesting to calculate the estimated burn time adjusted for the different starting temperatures of the water, but I haven't done that yet.

Full boil
Assuming that it will get colder again here at some point, I'll try to repeat the test at something closer to -20°C and I might also do a test indoors to get a good baseline to compare my results to. If any readers can contribute data on the cold weather performance of alcohol or other stoves, please feel free to comment.


  1. I use a penny stove -- and a pressurized stove similar to the penny -- at 2200m above sea level (right off my back porch), and I don't have too many problems. I just tested a design tonight, which the temperature was -12c. I had to heat it with about 5ml of additional fuel, but everything went pretty well. I also use these stoves at 3000m above sea level, too. This is in the late summer, however, the temps can still dip down below 0c, and, again, I don't have any troubles.

    For people to claim that the alcohol stoves do not work at high elevation, is both false and erroneous! I use them for a week or more, at 3km above sea level!

    If anybody has any questions you can contact me: NV6R_JWG (at) yahoo (dot) com

    1. Thanks a lot for your report! I never really questioned the performance of pressurized alcohol stoves in the cold or at elevation, especially most of the skeptics had never used a penny stove before. It was nice to see it for myself, though. This Montreal winter is exceptionally mild, so I probably won't be able to do another test at, say, -20°C, but I don't think that would drastically change anything anyway.