Homemade Backpacking Gear
by Jason Klass
Altitude and Boiling Times
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
|
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 barometeric pressure. Individual results may vary according to environmental factors. Information was comipled 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.