Feb 21, 2013 at 7:42 pm #1299570
@fluffinreach-comLocale: no. california
i am in no way sure if this subject has been visited previously. i did a bit of search for it, but if this be old hat, toss it in the dumpster.
how come we relate stove performance to Boil Time ?
it seems to me that the very act of deciding when and if the water is indeed boiling introduces some nasty inaccuracy into things.
could we not just agree (bwahahaha, on this list .. ) on a standard temperature rise ?
be it 100°F to 200°F, or 20°C to 90°C, either way, we 'd see how fast energy got shoved into our pot, and not have to concern ourselves with deviations incurred by determination of a True Boil state.. plus you get a running start on the timing as the temps rise.
digital t-meters are so cheap now that it's like owing a scale. almost a no brainer.
in an act of global conciousness and manners and questionable spellings and grammar … i recommend the 20 ~ 90° C rise be adopted.
no no noooo.. there's no reason to call this the Peter V. Standard … but thank you anyway.
the 20° starting point is for those of us without really cold tap water.
it's just a thought.
v.Feb 21, 2013 at 7:49 pm #1957214
@hknewmanLocale: Western US
To be scientific about it, there'd need to start at standard conditions in a lab setting. If all the stoves had the same starting temps, altitudes, etc, a real life comparison shouldn't be too much of a problem, but it should be stated in the review.Feb 21, 2013 at 8:18 pm #1957229
Hikin’ JimBPL Member
@hikin_jimLocale: Orange County, CA, USA
Just stating what the starting water temperature and air pressure (or at least elevation) would be a huge step in the right direction.Feb 21, 2013 at 8:41 pm #1957244
Tony BeasleyBPL Member
@tbeasleyLocale: Pigeon House Mt from the Castle
I do my stove test with the water at what ever the temperature it comes out of the tap, I then do the test stopping at 95ºC (where I live at 600 m elevation water boils at around 98.4ºC) taking note of the Canister weight before and after, I then normalise the results to give me fuel used in grams to raise 0.5 liter of water 80ºC, saves on trying to start with a set temperature which is very hard to do with consistency.
TonyFeb 21, 2013 at 9:13 pm #1957261
When I test my gear, I like to create easily reproducible conditions (albeit will not cut scientific muster) so I can compare equipment within what I would consider acceptable margin of error.
When I'm studying my canister stove, I at the very least factor in the following variables before making any assumptions:
1. The stove and how its underlying technology compares with similar stoves
2. I must assume that there are no defects with my stove (already not a scientific experiment) or purchase a number of stoves which I cannot afford to control for manufacturing defects (my kid plays hockey; not happening)
3. Fuel Source and corresponding characteristics at varying temperatures and altitudes (beyond me to measure purchased product)
5. Water purity, quantity, and temperature
6. Pot size, shape, mass, and temperature
7. Ambient temperature
1. Time from 40* to appropriate boiling temperature corresponding with appropriate atmosphere of pressure
2. Heat output of stove to achieve boil (currently estimating)
3. Fuel consumed by weight
I leave a few bottles of water in my fridge so they will be 40* when I run my tests; this works better for me than tap water to achieve a consistent starting temperature. My plan is to carry a thermometer with me this summer to calculate the average water temperature of the streams I cross in the Cascades to determine how close 40* refrigerated water represents what I will encounter in the field.
IMHO most fuel sources with the exception of canisters and bio fuel are easy to control for a test. I was in recent history (I'll humbly admit) on the losing end of a debate on the best way to test canisters. On a personal level, I have no interest in refilling a canister nor do I have the skill set and knowledge to measure the fuel mixtures commercially available fuel. This leaves too many variables unmeasured before I run my test and I'm forced to assume that Jetpower/Gigapower,MSR,whatever canister will perform within 10% of what I observe in a controlled environment (huge leap of faith).
Since I do not have the resources to conduct a truly scientific test at all temperatures and altitudes, I compensate by allowing for a measured margin of error and back up my canister stove with an appropriate number of Esbit tablets, or on a longer trip, an extra canister.
For example, I know that my Soto stove will boil 14 pints of 40* water at 400' at 32* ambient temperature. If I'm on a lazy week long solo trip in late spring at 1000' where I'm boiling water twice a day, I'll pack two extra Esbit tablets, won't bring water to full boil, and maximize the use of my cozy to mitigate the larger margin of error resulting from my inability to control for fuel consistency and unknown variances in stove output due to productions inconsistencies.
I do not have the time, money, or laboratory resources to analyze my equipment to reduce the margin of error and quite honestly it would never pay for me to make that investment.Feb 22, 2013 at 7:25 am #1957347
Jerry AdamsBPL Member
@retiredjerryLocale: Oregon and Washington
I do it like Tony – try to stop about 95 C or so but normalize so it's not critical
I use about 5 g of fuel so the cheap scale I use to weigh equipment with has a resolution of 0.1 g will have 1 part in 50 error which is good enough to compare two different stoves or windscreens or whatever. Just make sure and wipe off condensation which might weigh something like 0.1 g.
And I weigh the canister before and after each trip. For most trips, I heat 3 pints each day, I'll just divide fuel used by number of days. I've found I use about 1 ounce per day. Then, I'll weigh the canister before a trip and if I have close to 1 ounce for each day or less, especially if it's really cold, I'll either take a new canister instead or maybe just heat a little less water for each pint of coffee or maybe I'll run out on the last day and miss my 2nd cup of tea.Feb 22, 2013 at 7:57 am #1957363
Stuart RBPL Member
The difficulty with stove testing is that there are so many possible variables involved. There is not even a consensus about what the best thing to measure is: time to boil or amount of fuel required to boil. Whatever set of conditions are decided upon, it is very hard to reliably reproduce real-word conditions in an controlled environment. So, before you even start, decide whether the answer to the question you are asking will actually be useful.
Although I have tested some of my stoves, I found that this did not provide a useful answer the question of interest to me: how much fuel do I need to bring on a trip of X nights for Y people? The best way I found to answer this is to look at how much fuel I used on a previous similar trip and then extrapolate from there. To do this I keep a spreadsheet listing grammes of fuel used on previous trips along with the various factors involved.Feb 22, 2013 at 10:14 am #1957399
The following information is helpful in making meaningful comparasions between stove systems and boil time measurements:
-basic cooking system description (stove type, pot type/dimensions, windscreen, lid)
-basic test method (e.g. an ave of 3 boils, stove and pot cooled btw boils, performed in kitchen)
-amount of water (hopefully in grams)
-amount of fuel used
-type of fuel (esp for alcohol stoves)
-time to boil
-overall temp change
-ambient tempFeb 22, 2013 at 10:15 am #1957401
deleted – impatient double post
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