Several times I have mentioned that it seems to me that the 12-10 burner uses less fuel if you start with more than you will burn.
So for example I can boil 500ml from around 15c with about 14g (18ml/0.61 fl oz) of Ethanol pretty regularly but I need to start with about twice that.
If I measure just 14g it will burn out before I get a boil.
The other day the thought that the extra fuel is keeping the burner cooler popped into my head .
Does this make sense ?
Franco
BTW, that is why I use a snuffer, just never really thought of why it happens.

I cannot say for sure that with the 12-10 stove this is true, but I feel like this is a accurate assessment.

I have noticed the same thing with my WBS in the past. Once the fuel starts to run out, the stove does burn just a little less hot, so that can make a definite difference. However, if there is enough fuel in the stove to keep it burning at max temp for longer times, this does indeed bring the water to a boil faster.

As well, if you are using a snuffer, this is a simple thing to do...

Check out some of my boil times with my WBS using different amounts of fuel:

http://sticksblog.com/gear/kitchen/stoves-extras/white-box-stoves/

The extra fuel should not be a problem, one way or the other, as long as you have an easy fuel recovery system. With my 12-10 burner, I can recover about 95% of what is remaining.

--B.G.--

Do you use the featherfire fuel bottle or something else, Bob? I've been curious about this too, as I agree with the OP, that the fastest boil times come from using more than 20 ml. of fuel.

"Do you use the featherfire fuel bottle or something else, Bob?"

I use a standard plastic fuel measuring cup. I just tilt the burner until it dribbles out, but it is necessary to rotate it to get the dribble going right.

--B.G.--

"but it is necessary to rotate it to get the dribble going right."

Must ...... resist .......

Gosh Bob, why'd ya want to tempt me like that! ;-)

helps if you give it a good shake too.



edited to add photo

Edited by Franco on 09/10/2012 19:02:10 MDT.

I only had this happen once on my vacation a month ago. One night I had to boil over 2 cups of water, that boiled faster than a night or two later where I only had to boil 1.5 cups. No temps taken of the water. Of course starting with more fuel for the 2 cups of water. Worth looking into. I picked up a CC and a Evernew .6 ti pot and tried it on a camping trip a few weeks ago. It kicked butt on boiling 1.5 cups faster than my CC with .9 ti REI pot. Also one thing I noticed with the smaller pot, the CC itself is the same height as the CC for the larger pot. The small pot is shorter too, so the flame is further away from the pot. I'll have to try a few experiments armed with my results and what others are seeing. Quality time with my stoves. Woohoo!!!
Duane

helps if you give it a good shake...

thats good Franco, got a laugh out of me. no more than two shakes mind you...

Edited by mrjones on 09/11/2012 03:29:23 MDT.

Yes. I had some data that proved this, but it was lost with the rest a few years ago with the hard drive. Anyway, as I recall, there was like a 15 second differential for two cups of water boiled to 200F from 40F. This was over the couse of like ten or twelve burns as I remember. It drove me a bit crazy because everything was "supposed" to be equal...pot, cone, water temp, etc. I was doing the same as Franco and simply snuffing it out when I got done with each test run, though. Then adding an ounce of fuel. It did bias the results as the stove filled more and more. I tossed those results and simply let it burn out each time and ignored it.

The reason? Well, not real sure, but I suspect you are correct about the fuel cooling the stove. More specifically, the chimney area. The differential heating between the top and bottom (as well as the actual combustion) causes air to be sucked into the flame. If it has more differential, this is roughly the same as making a longer chimney column, it means slightly more air, hence more combustion or a hotter flame. Again, I have not really looked at this specifically, since I simply built a taller chimney stove with more air inlets (yes, it does burn hotter though it has a smaller heat outlet.)