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Fuel usage per day OH vs canister


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Home Forums General Forums Food, Hydration, and Nutrition Fuel usage per day OH vs canister

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  • #1815705
    James Marco
    BPL Member

    @jamesdmarco

    Locale: Finger Lakes

    Bob, It depends on the calculation used.
    Ounce: 1 ounce = 28.3495231 grams
    Ounce (fluid): 1 US fluid ounce = 29.5735296 milliliters or grams of water to allow conversions.
    OR
    1 gram = 0.0353 ounce or about 0.034 fluid ounce of water.

    Anyway, yes. Your SLX probably weighs funny.

    Alcohol does not have the same density as water
    (from http://www.simetric.co.uk/si_liquids.htm)
    It is roughly 79% of water for methanol and 80% of water for ethanol.

    I just use 80% and forget the difference. I think it is slightly higher for ethanol because of the water component, anyway. WG is approximatly the same…I don't try to evaluate all the different stuff in it. .8 is a good rule of thumb.

    #1815715
    James Marco
    BPL Member

    @jamesdmarco

    Locale: Finger Lakes

    "The definitive BPL article on carry weight for alcohol vs. canister stoves vs. other systems: http://www.backpackinglight.com/cgi-bin/backpackinglight/comparative_fuel_efficiency_and_weight_of_stoves_pt2.html"

    Unfortunatly, I cannot believe this test or Will's conclusions. Will states that his ground rules, or premises, are: "If I chose the lightest stove in each category and used it as efficiently as I could, how would the cooking system carry weights compare for different usage levels and trip lengths?"

    But, this leads to false results and overall conclusions.
    An example: The lightest WG stove.
    The Simmerlite is indeed a light stove, but it does nothing well. I use it as a car/base camp stove only. Fuel efficiency is one of the worst I have ever used. It takes a lot of fuel simply to light it, nor, is it capable of low heat settings for any length of time.

    A second example: He has alcohol OUTPERFORMING white gas in his charts. Given the difference in heat content of the fuels, this is not even reasonable.
    Canister Gas:Kerosene:WG:Esbit:Ethinol:Methinol is the heat density order. Any test that does not follow this, is suspect. I would be forced to conclude that alcohol produces more heat than WG, by this test?

    #1815717
    Jerry Adams
    BPL Member

    @retiredjerry

    Locale: Oregon and Washington

    "Canister Gas:Kerosene:WG:Esbit:Ethinol:Methinol is the heat density order. Any test that does not follow this, is suspect."

    You have to include the weight of the stove and other stuff.

    Alcohol stoves weigh very little so they're best for shorter trips.

    Since alcohol has lower heat density, you need more weight of fuel per day, so as your trip gets longer, canister stove becomes best.

    You should suspect any test that doesn't reach this conclusion.

    #1815720
    Brad Rogers
    BPL Member

    @mocs123

    Locale: Southeast Tennessee

    I used the weight of pure ethanol (which I know denatured isn’t, but it was the best value I could find) which is 0.789grams per mL which gives me a weight of 11.835grams per boil. That may or may not be correct, but that was my logic.

    Seve,

    I don’t do breakfasts or hot drinks, so I only boil 12oz of water per day. The more water you boil, the less since alcohol makes since it doesn’t produce a lot of heat per ounce. However, for me and my trips of 7 days or less, it is the perfect fuel. On the other hand I can get 17 12oz boils from a 110g canister, but I am never out long enough to make that worth it. If I boiled three times a day, it would be more weight conscious over a week long trip than alcohol .

    #1815977
    Steve S
    Member

    @idahosteve

    Locale: Idaho

    Brad, that would make sense. On my shorter trips I do use my gram weenie, and I love its simplicity. I also don't eat quite as much on shorter trips. I have worked on what it would take to do a really long self supported trip, and I believe I could stay out for close to 12 days without going over 35lbs. I put that together looking at a trip into the Wind Rivers. I hope I can get the time to find out! The even larger cannister would be a great asset for something like that.

    #1816070
    James Marco
    BPL Member

    @jamesdmarco

    Locale: Finger Lakes

    "You have to include the weight of the stove and other stuff.

    Alcohol stoves weigh very little so they're best for shorter trips.

    Since alcohol has lower heat density, you need more weight of fuel per day, so as your trip gets longer, canister stove becomes best.

    You should suspect any test that doesn't reach this conclusion."

    Exactly my point, Jerry.

    The canister stoves are an exception to the general rule when you consider the total weight of fuel needed for a trip. They are about doubled in weight for the fuel carried. There is no way around this.

    My consumption is large by any standard. I need about 2.5 guarts per day.
    4 cups in the morning of water boiled: 2 cups for oatmeal(6-8oz), 2 cups of coffee(8-9oz)
    Nothing till supper.
    About 4 cups for soup/stew, about 2 cups of cocoa after I prepare for bed.

    Assuming I have to carry everything, this means a 113g container will last three days. So, for 7 full days out, I need three, 4oz canisters worth of gas + three 4oz cans. Or about 24oz in fuel or weight related to carrying fuel. At the end, I am still carrying a minimum of 12oz in dead cans, assuming I empty any leftover. Adding in for the stove, I make it about 27oz starting weight with a final dead weight of 15oz. Even using an 8 ounce can it really only saves about 5 ounces. Leaving a starting weight of around 22oz and a final weight of 10oz. Perhaps it is possibleto do about the same as alcohol with 16oz cans, but these are difficult.

    Assuming .5oz alcohol/pt that means about 2.5oz per day for 7 days is 17.5oz. Since the actual fuel weight is about .8 that of water,the fuel weight is carried is about 14oz. Put in a 2oz pop bottle (being generous here and adding in for an extra cap, with filler hose) The total weight carried would be 16oz. The stove and a caldera cone: weight about 5oz. I make the total starting weight 21oz with a final dead weight of 7oz.

    Assuming about .5oz/qt for my WG stove, I need about 1.5oz per day. For 7 days, I make this about 10.5oz, but the fuel density is again, around .8 for a carry weight of 8.4oz plus 2oz for the bottle, or a carry weight of 10.4oz for fuel and ~17oz for the stove. Total weight carried is about 27.4oz at the start with a 19oz final weight.

    Conclusion:

    Canisters NEED a can to contain the fuel approximatly halving fuel density, you simply cannot contain the fuel in any usable form, otherwise.

    Canisters and alcohol flip flop between what is best due to the step function related to canisters. Another day would show a slight edge to alcohol possibly break even. Another day would give a slight edge to canisters. I say slight because the carry weigh at the end of the trip means that this weigh needs to be considered as dead weight for the entire trip. At the end of a trip, canisters are badly handicaped by the can because they still need to be carried. Roughly, alcohol and canisters are about break even for overall efficiency but canisters hurt the pounds carried per day.

    It only matters about WG because the STOVE is heavy. The fuel itself is actually the most efficient to carry. But, as you say "You have to include the weight of the stove and other stuff." This becomes the heaviest to carry.

    #1816071
    Brad Rogers
    BPL Member

    @mocs123

    Locale: Southeast Tennessee

    Steve, I would agree that a trip of that length that a canister stove would be best. I have a Gram Weenie Pro, but have found that it uses a lot of fuel to boil water, easily double what the Caldera Cone Uses. The Winds look like a great place, I am looking into a trip there myself this summer, but probably only 6-7 days.

    #1818141
    Paul McLaughlin
    BPL Member

    @paul-1

    Boy, we see this question or one like it often. So it would be great if Roger or Will (or both) could do a real-world based test on this – how about a Snow peak upright, a jetboil Sol, a Whisperlite, and an alcohol stove, head to head in say 50 degree air temperatures, boiling a liter or a 1/2 liter at a time, cooling the stove down completley after each boil, and doing something like 20 boils or so each, so there is some nice data to look at? And of course we'd also want a cold-weather test, run at say 20 degree air temps, and run long enough to use up a full canister on the canister stoves.

    Pretty please with a cherry on top?

    #1818165
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    There's a LOT of test data in some of the stove articles already. Could be worth reading through them first.

    Cheers

    #1818172
    James Marco
    BPL Member

    @jamesdmarco

    Locale: Finger Lakes

    Yeah, too many tests. The overall fuel used is based on a lot of things. Mostly, it is NOT based on daily use. It isn't based on terrain, or, hiking style. It isn't based on resupply availibility. Hence these discussions are more of a check for an individausl hikers choice. Except for the short, unresupplied trips where no more fuel is needed, or, the occasional 3-4 week long unresupplied trip where every gram counts because your starting weight will be mostly dictated by your food(35-50lb of it,) most hikers opt for stopping to resupply fuel, hence don't carry everything.

    High calorie densities often means a small amout of cooking. Pasta, cous-cous, vegetable fats and oils, dehydrated vegies, dried meats, and raw flour (or bisquick) make a lot of interesting meals, but take fuel to cook.

    Boil and dump Mountain Hut gets old in a hurry, and is a bit heavy. On a short weekend trip, 2-3 days, it doesn't really matter. Longer and it starts tasting like chemical soup and gets real boring.

    Too many different hiking styles for any tests to have relavency without considering the terrain you will be hiking over. These mean that tests are sort of worthless. What good is a stove that you cannot get fuel for because the local store doesn't stock Yellow HEET, or SLX, or White's Lightnin', or even good spirits? "30 miles down the road." is ALWAYS in the wrong directon, 'ya know.

    #1818233
    Jon Fong
    BPL Member

    @jonfong

    Locale: FLAT CAT GEAR

    There is an old golfing phrase “if you want to get better at golf, start counting your strokes". I highly recommend that whatever stove you use, get use to your system. This is a chart that I did when we took a summer trip to Sequoia National Park. We averaged 9 ml of fuel per cup of water. Note that I temperature compensate for fuel usage. Starting with 70 F water, it takes me 15 ml of S-L-X to boil 2 cups of water (~140 F delta) that means it takes about 1 ml to raise 2 cups of water 10 degrees. If the water was ice cold, I add 4 additional ml (I round up to 20 ml).

    Fuel used on Rae Lakes Loop

    Those of you who are really into reducing fuel volume as low as possible may need to consider 1) bringing near 100% ethanol and diluting it on the trail or 2) experiment with DA mixed with IPA or WG. Personally, I think that those options are a pain and would just carry a bit more fuel. My thoughts anyway – Jon

    #1818476
    Paul McLaughlin
    BPL Member

    @paul-1

    Roger – I've read most (if not all) of the stove articles on BPL, and yes, lots of fuel usage data – for the various canister gas stoves. But almost none for any WG stoves, and none that directly compare the two which is what really interests me. Unless I have missed something, in which case I would appreciate being directed to a particular article.

    #1818567
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Hi Paul

    Ah well, WG. I guess I have been a bit light on testing fuel efficiency for WG stoves, but that's because past experience has shown (me) the following (wrt canister)
    They require about 50% more fuel
    They emit a lot more CO
    They are generally a bit less powerful
    The total weight is much higher

    Cheers

    #1818639
    Steve S
    Member

    @idahosteve

    Locale: Idaho

    I did boil thru a full cannister after buying my Snow Peak Litemax stove. It was enlightening, and boring, but ultimatley helped a bunch. Even doing it inside with no wind, just seeing the consistency and timing the boils helped me with future planning.
    I tried to paste over my spreadsheet, but it went nuts after I posted it…..

    bottom line is I got between 7-8 liters of boiling from the small 3.88oz can. Burn time was over 60 min.

    #1818675
    Bob Bankhead
    BPL Member

    @wandering_bob

    Locale: Oregon, USA

    I prefer to think in terms of the number of liters boiled per cannister, using a windscreen but no heat shield/reflector plate thingy.

    "Boiled" means bubbles actively (but slowly) rising from the bottom; not a rolling boil that lifts the pot lid. That's all I need to rehydrate freeze-dried meals and to make soup or drinks. My mouth rebels violently at contact with anything over about 130°F. YMMV.

    These values are long-term averages that included a wide range of water temperatures, altitudes, and wind speeds here in the Sierra and Cascade mountains of the Pacific NW of the USA.

    I can get 7 liters out of the small 4 oz / 113 gram net cannister

    I can get 13 liters out of the larger 12 oz / 227 gram net cannister.

    I haven't used the super-size-me cannister; it's just too bulky and heavy for me.

    That said, I long ago switched over to Esbit tablets (and lately a Caldera Cone) for solo trips. The cannister get selected if I have to share a stove with someone else.

    The alcohol stoves that came with my 3 Caldera Cones are still lying unused in my gear cabinet. I've never been fond of alcohol mostly because it is almost impossible to see the darn flame in the daylight, and the thought of a fuel spill and the potential fire it could cause gives me pause. But that's just me.

    I avoid snow camping and sold my old MSR white gas stove decades ago. However, if you snow camp in cold weather, nothing beats white gas for BTUs and efficency (IMHO).

    .

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