Altitude – Boiling Times · Temps d’ebullition

by Jason Klass

One of the most frustrating things for stove builders is when you make a design you found on the Internet and cannot replicate the boil times claimed by the inventor. There has been much discussion to account for this phenomenon including environmental factors (such as wind and temperature), windscreen placement, pot-stand height, pot width and thickness, type of fuel used, etc. While all of these may be influential factors, there is one important consideration that I feel has been largely ignored: altitude. Most people know that water boils at lower temperatures as elevation increases. And, in turn, a lower boiling temperature means a faster boil time. The formula goes something like this:

The boiling point of water is reduced by approx. 1.9 degrees for every 1,000 ft. in elevation gain.

Boiling Point vs. Elevation

If you are at sea level and are consistently getting a much slower boil time for a stove that was developed and tested by someone who lives at 8,000 ft., altitude may very well be the culprit. Therefore, I thought it would be helpful to post a chart showing the boiling point of water respective to elevation. (*)

Feet Meters Degrees Farenheit Degrees Celsius
0 0 212 100
1,000 305 210 98.9
2,000 610 208.2 97.9
3,000 914 206.2 96.8
4,000 1,219 204.4 95.8
5,000 1,524 202.6 94.8
6,000 1,829 200.7 93.7
7,000 2,134 198.7 92.6
8,000 2,438 196.9 91.6
9,000 2,743 195 90.6
10,000 3,048 194 90
11,000 3,353 192.1 88.9
12,000 3,658 190.2 87.9
13,000 3,962 188.1 86.7
14,000 4,627 187.3 86.3

* All boiling times posted are based on consistent barometric pressure. Individual results may vary according to environmental factors. Information was compiled through a variety of scientific and non-scientific sources as well as my own calculations.

Caveat

My goal in posting this chart is solely to provide a reference for the properties of water. In itself, it does not directly reflect the performance of any stove design. There are many other factors that influence the boil times of alcohol stoves (which see); however, I think this chart can provide one more useful insight into alcohol-stove performance.

Conclusion

So, before you condemn a stove based on your results, consider the usual suspects such as fuel and design but don’t forget to put altitude under the microscope as well. You might find it to be the main difference in discrepancy of stated boil times.

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