[pct-l] Hiking in 2008: simmering stoves - 2

[Denis Stanton]

On 24/01/2008, at 6:21 PM, evan battaglia wrote:

> I met a guy on the AT who brought two pop can alcohol stoves: one  
> for boiling and one for simmering. The simmering one had less holes  
> I believe and thus put out less heat. He said the "simmer rings" for  
> other alcohol stoves don't really work so at 0.2 oz or whatever a  
> coke can stove weighs, why not bring another one.

Ah, at last a question that I can claim some experience on.

My daughter did a science project on efficiency of coke can alcohol  
stoves.  We made up eight with different numbers of holes and somehow  
it became my task to boil 380 cups of water, one at a time, with  
stopwatch and thermometer.  What we found was that the number of holes  
above eight made very little difference (we had 8, 16, 24 and 32).   
Fewer or smaller holes used less fuel, but not by much.  The most  
important factor, in a can stove with no adjustable vents, was the  
distance from stove to pot.  The closer you put the stove the longer  
and slower the burn.  With a 1 cm gap (0.4 inches) we could boil 250  
ml (1 cup) of water for 19 minutes.  Increasing the gap brought the  
water to the boil faster but wasted fuel and reduced the boiling time  
to 6 minutes at 5 cm (2 inches).  At that distance we were getting an  
inefficient orange flame and a sooty pot at the end.  All tests were  
performed inside so crosswinds were not a problem.

Below is a clip from our results. The table below may not look  
straight in your mail program.  5 cm -> 5 mins 53 secs, 1 cm -> 19  
mins 18 secs

All test groups for a given distance have been averaged to reduce  
comparisons to a single variable, the distance between pot and stove.

5 cm	3.5 cm	2 cm	1 cm
05:53	07:06	10:46	19:18

Here are the results for number of holes -> minutes

All test groups for a given distance have been averaged to reduce  
comparisons to a single variable, the number of holes in stove.

8 holes	16 holes	24 holes	32 holes
10:08	07:43	07:38	07:21

<I had some photos here but my mail didn't appear on the list so I  
guess there's some sort of filter to prevent overload.  You'll have to  
imagine my stove test rig>

Denis Stanton
denisstanton at mac.com

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