Comparative Fuel Efficiency and Carry Weight for Six Lightweight Backpacking Cooking Systems: Part II

[Cat Jasins]

Companion forum thread to:

Comparative Fuel Efficiency and Carry Weight for Six Lightweight Backpacking Cooking Systems: Part II Calculating Fuel Usage, Carry Weight Analysis, and Cost/Efficiency Considerations

[Eric Martel]

Hi Roger,
Yes excellent point. I reran the number and updated the chart.

The break you see in the curve for the canister systems are due to the added canister. For the White gas it is due to a change in the MSR fuel bottle.

[Roger Caffin]

Hi Eric

I am not sure I agree with all the assumptions about fuel use – on my figures the top-mount should run flat to day 13. However, no matter.

What is interesting is that for anyone who resupplies at weekly intervals or less, the Jetboil never wins over something like a Snow Peak & Ti pot. I can't argue with that!

Cheers

[Eric Martel]

It depends if you are speaking of cooking days or hiking days. On my chart it runs flat to day 12 (cooking days) which is equivalent to 13 day hike.

I am using Will's fuel consumption.

I was surprised that the Jetboil faired better than white gas. Now this is comparing stoves in similar relatively mild condition. Also as someone mentioned there is most waste in Alcohol stove that I wil try to incorporate.

I very surprised how the fuel tab performed frankly I never even considered fuel tab as an option.

In another article from Will he discusses Windscreen an it is very intersting to see how each of the cooking system perform.

I also ran the numbers based on Highland consumption. I'll post that later today.

[Jim W.]

I enjoy carefully researching and analyzing my options- which drives my wife nuts.

When I decided to buy a Jetboil last year I had already come to the same conclusion- that it would never be the lightest canister system before about 12 man-days of cooking. The places it comes out ahead are convenience and safety.

[Greg Mihalik]

"Also as someone mentioned there is [more] waste in [an] Alcohol stove"

Using a Packafeather bottle top there is NO waste. You can aspirate any and all unused fuel back into the bottle.

This will work on almost any poly fuel bottle with just a little futzing around.

[Derek Goffin]

I am a Jetboil enthusiast. It is clearly partly about other things than pure weight, like convenience….
A lot of these things depend on your assumptions so here is a Jetboil oriented pitch
I have cut down my Jetboil to weigh 300 grams, this involves cutting the pot down to 800 ml equal to the other pots being talked about, discarding the heavy lid for foil and other things that only take a hacksaw, scissors and file.
I have a Primus Ti micron and a MSR Ti Kettle or a Caldera Cone alcohol setup as my Alternatives. There is nearly always 2 of us and sometimes 3
With 2 of us I think it is sometimes lighter to take my jetboil than either of the alternatives if I am cooking for 3 days without resupply. This is based on heating 2.5litres of water to boiling per day. We can make a 110ml canister last 3 days whilst the Micron is on to a larger canister. As soon as there is a larger canister involved my jetboil is lighter.
As far as Alcohol is involved the solo alcohol user says "I dont care that it takes ages to cook with Alcohol I have all evening". Firstly in the mornimg we often need to be away quickly. Second in the evening I would like to see what people make of cooking for 3 on one solo alcohol setup. I can still cook for 3 with my cut down jetboil, it might take longer but not as long as the alcohol setup. I think with more than a solo trip time matters and the alcohol weight should be redone to carry 2 solo stoves and all extras times 2 for two person trips.
In my opinion alcohol also crosses to heavier at 3 or 4 days without resupply (this is still for 2 people) and it is harder to light and less convenient. More difficult in cold and wind etc. Hard to get the amount of fuel right etc. For a light summer weekend I do use the Caldera cone and probably its worth it for 2 days, then it depends.
Finally I dont know whether it is me or where I hike but I can often be sure of resupplying with food in a strange place but find it hard to be sure that I can resupply with gas or alcohol unless I have been there before. You cannot send fuel through the post or fly with it. It is often easier to buy the fuel for the whole trip at the beginning and not have to worry about it. I can easily end up carrying 26 person days of fuel to save uncertainty.

[Eric Martel]

I think we mentioned waste with alcohol not necessarily with respect to recycling unused alcohol but about priming the stove and also about the user not turning out the stove right away and about spilling.

[Eric Martel]

Here is a comparison between Low land and Highland . Sames assumption except that the fuel consumption is different AND the fuel container is updated as needed

Low Land

High Land

[Eric Martel]

Just for kicks I added a waste of 25% white gas and 50% for alcohol stove. The Jetboil people will be happy.

Low land consumption with waste

High land consumption with waste

[stefan hoffman]

What would you consider Highland and Lowland? 50% waste for alcohol….that would take some serious talent, and Palsey like Ali. There are houndreds of variations for using each type of fuel, perhaps it would be a little more definitive to leave out the base weights and focus on the only REAL variables in the equasion (fuel and container). We all know our base weight, and its not likely to be the same as the assumed weight on the graph. It could make it more universally applicable to those considering multiple setups. And come on, a cat stove?….did you really need to handicap the alcohol crowd that badly? :) Tons of variables here, but a very good attempt at simplifying it.
Thanks- Puck

[Eric Martel]

Hi Stefan,
The definition of Lowland and highland is as defined in Will's article. I am very clumsy with alcohol stoves. But the question is: if you are going on a 7 day hike with no resupply, how much extra alcohol will you bring with you? May be 50% is not the answer but it will not be 0% either.

About the real variables the question I am trying to answer is: What are differences in weight for each of the cooking system depending on cooking days? I think that the stove weight are real variables because Bring an integrated Canister system with a trek 700 will do me no good at all. So just looking at fuel and container will not help me answer the question.

With respect to the alcohol stove I believe I was helping the cause of the alcohol stove by include the cat stove at .3 oz. The fuel consumption is entirely based on Will's article and I don't know which alcohol stove he used. Do you have an alcohol stove lighter than .3 oz?

Exactly this chart is just meant to be a comparison, it is not meant to calculate your fuel needs for your next expedition. Unfortunately simplifications are necessary in order to compare adequately.

Just for fun here is what the chart would look like if we only look at Fuel and container. This is the lowland consumption with the white gas and Alcohol waste factors

Same as above with no waste

[Jim W.]

Watch out for Jetboil apologists.

Like I said- it's the ease of use more than the efficiency for me. I do sure wish it had a way of indicating that the water was hot without having to lift the lid or look for steam. Maybe some sort of thermal indicator on the cozy. You would know in a Flash if it's hot.

Anyway I've been planning a family trip. Two adults, two kids. I figure a reasonable daily estimate of boil needs are 4 cups for each kid, 6 cups for each adult. Breakfast will require 2 boils for drinks and 1 for porridge. (8 cups total). Dinner will require 4 boils for soup, rehydrating food, and drinks (12 cups total). Daily total of 20 cups (5 quarts) will require 50 grams of fuel. One 220 gram can will give us 4 nights' fuel.

[Jim W.]

Personally…
-With a canister it's difficult to gauge remaining fuel in the field. You slosh it or dribble hot water on the side to see where the temperature changes- but the domed bottom makes it hard anyhow.
-With gasoline you can look in the fuel bottle- but not so easy to get an accurate volume by eyeball. I have used my hand on the side for temperature change or used a tent peg as a dipstick.
-I've never used an alcohol system, but a translucent bottle seems to make gauging fuel very easy. Don't bring extra, just ration the allotment. If that means fewer/smaller cups of tea so be it. At least you don't have pasta in ice water the last night.

If you overestimate with non-pressurized fuel it's a lot more fun. One winter trip my buddy and I brought 2.5 liters of white gasoline for 9 nights. We ended up ahead of schedule, plus weather was fairly mild, plus the stove was more efficient than we had estimated. With two nights to go we clearly had more than 1 liter extra. The fuel, a small log, a flat rock, and a pile of pine needles made a very, very impressive pillar of fire.

[James Dubendorf]

I would like to mention two things about alcohol stoves that influence my choice of the system in some situations. First, while alcohol is heavier per BTU than other fuels, it also becomes lighter much faster as you are on a trip. I lose about 1.4 oz. per meal of fuel when cooking for two. Even if I start a trip w/ canister and alcohol systems weighing roughly the same, the weight of alcohol system quickly becomes lighter, but the canister stays relatively heavy- and by the time I finish up, the alcohol system is MUCH lighter.

As for bringing additional alcohol to account for varying conditions, I do bring some. But since I can measure exactly how much alcohol I use, and I know exactly how much I have with me, I can accept hot but not boiling water if the conditions are harsh (in practice, this is pretty rare where I cannot set up a decent shelter for the stove). I'm ok with this, even if I don't reach the ideal water temperature, because my cozie still works its magic. So, harsh conditions don't necessarily imply unlimited fuel consumption if you are equipped to deal with slight variations in water temperature.

James

[Tim F]

I think James makes a good point about quickly diminishing weight with alcohol, and I would add solid fuel, systems. I saw a graph or chart pertaining to daily average weight of different cook systems and fuel that emphasized this difference over 14-day and 28-day periods. Might not be extremely relevant for the time lengths (I don't know too many peope that go 14 days unresupplied, let alone 28 days!), but it was an eye-opener. I think this was at thru-hiker or whiteblaze.

On another note, I re-read the article for the first time since my conversion to solid fuel, and some of the numbers seem off for the fuel tabs. Table3 shows .43oz per boil for Highlands and .3oz per boil for Lowland conditions. But in Table5, under "Fuel tabs needed / day", for boiling 1 pint/day in Highland conditions it says .4 FUEL TABS, not OUNCES, per day. Likewise, Table6 indicates that for 3 pints/day in Lowland conditions you need less than 1 fuel tab/day (I wish!). It seems like these sections should either be labeled "Ounces of fuel/day", or all the numbers should be doubled since a fuel tab is .5oz. Am I reading this wrong?

Tim

[Eric Martel]

In my chart I assumed that you couldn't reuse the fuel tab and therefore had to use .5 oz.

[Eric Martel]

Just to highlight James point above. I have yet another chart (last one promised. I like pictures) showing how the weight of the cooking sytem is reduced over the duration of a 7 day trip and the alcohol has the lowest ending weight.

[Tony Beasley]

I am not sure what alcohol Will used in his tests but I have just finished doing hundreds of tests with alcohol stove fuels and I think his lowlands amount specified of 0.38oz 10.9g is only obtainable using the most efficient stove, best alcohol in perfect windless conditions, I would add at least 10-20% for in the field and lot more if using Methanol (HEET).

His canister gas amounts for the JB are close to mine, his top mount canister, and remote canister stove figures are a bit higher than the figures I get. (Though I have not tested the MSR windpro that Will used it might be an inefficient stove)

Tony

[James Dubendorf]

I don't want to draw this thread in an entirely different direction, but there are plenty of strategies for fuel consumption and conservation that can influence the lines on the graphs above. The attempt to accurately predict consumption is inextricably linked to how fuel is actually used.

I use a homemade open jet pepsi can stove, a fairly robust aluminum flashing windscreen, and a firelite sul 1350 pot to cook for two people over multiple days, averaging 4-5 cups of boiling or nearly boiled water/meal. I appreciate the complete stability and protection of the windscreen, which doubles as pot stand, and so am willing to make the weight sacrifice there. A few suggestions on conserving fuel that directly address alcohol, but I suppose are broadly applicable.

1) My cooking routine involves about 2 cups water for food preparation and another 2-3 cups for beverages. I first boil 3 cups, then quickly scoop out 2 cups which go into the waiting food container, all the while leaving the pot on the stove. I then quickly add another 1-2 cups water to the pot, and that is for beverages when it is done. This means that the pot is never off the stove, the pot is never empty, and fuel waste is minimal. If the container in which the food soaks is aluminum or titanium, place it on top of the main pot as it heats to absorb excess heat.

2) My mentality is not to use as much fuel as I need to achieve a desired water temperature, but to achieve as high a water temperature as I can given a specific fuel ration, usually 50 ml alcohol/meal. This doesn't mean I am accepting warmish morning coffee! Under most conditions this is perfectly adequate and even allows a little wiggle room. But if I ever am in a rare situation where conditions severely degrade the performance of my stove, I can always opt to accept my non-ideal coffee or food temperatures as the price of business. Of course, if it is nearing the end of the trip, I will happily splurge on extra fuel (and if I am in an area that allows fires, this can always be a last night option if all fuel is consumed). If fire is an option, running out a fuel is not a big deal. If you know your alcohol stove well and are able to accurately dispense fuel during your trip, these calculations are pretty straightforward.

3) As I mentioned above, the use of a reflectix coozie can compensate for loss of stove efficiency in these situations. I read somewhere on Andrew Skurka's site that he boils less than the required amount of water, then adds cold water to the food mix to achieve an ideal consistency and bring it to an immediately edible temperature. Little tricks like this can amount to real savings as trips extend in length.

4) If camping in an exposed area where stove performance will suffer, or if mornings start very cold but warm up quickly, breakfast can always wait. Grab a quick bite, head off on the trail and plan to rest mid-morning when it is warmer and, perhaps, you have entered more sheltered surroundings. If you absolutely need that caffeine fix first thing, carry some chocolate covered beans to tie you over!

The more experience you have with your stove in different conditions, the easier this becomes. And by the time you return to the trailhead w/o any excess fuel, even a very luxurious and robust alcohol system still comes in under 5 oz.

[Eric Martel]

I normally wait for the water to boil before using. I have a question. It takes about 35 Kj to bring water from 20C to 100C boiling point but then it takes 225 Kj more to bring it from 100C to vaporization.

It sounds to me that if you had a thermometer you could stop your water heating when it reaches 100C instead of bringing to a boil and save a lot of energy.

Any experience on this?

[Dan Cunningham]

James – you are right on. There are tons of factors that play into how much fuel each person will use. I think it's very hard to say that one method or another is more efficient because of so many external factors.

My alcohol setup weighs .75 oz for the aluminum flashing windscreen/stand, .5 oz for the stove, and 3.5 oz for my snowpeak 700 with a custom lid. It'll boil 16 oz of cold water on 2/3 oz of alcohol in 5 minutes or so. It ends up being pretty efficient, even for two people with a longer time between resupply. I could grab another setup that will boil more water with less fuel, but it add more weight. It depends.

Some things that will affect any method that attempts to compare stoves using days of fuel in some sort of standardized manner:

– number of people cooking for
– amount of cooking required per day (coffee, tea, wash-up?)
– personal methodologies/styles
– type of stove (efficiency, weight)
– size of cookpot (efficiency, weight)
– windscreen design (efficiency, weight)

There are obviously more factors than this. Stove efficiency is very useful to compare, but when comparing them as weight carried over days, it will be different for almost every person. You'd have to compare the stoves you have at your disposal against your situation and style.

[Tony Beasley]

Hi Eric,

>I normally wait for the water to boil before using. I have a question. It takes about 35 Kj to bring water from 20C to 100C boiling point but then it takes 225 Kj more to bring it from 100C to vaporization.

According to my books and calculations it takes 4.18kJ/(kg.K) to heat 1kg (1 liter) of water to a temperature rise of 80C, it would take 334.4kJ then when the water turns to steam it takes 2256kJ/kg to do so.

During the heating process there is some steam produced but according to my measurements it is only a few grams worth, usually less that 5g this would be a maximum of 11kJ of energy, of course if you kept the heating process going and turn all of the water that you are heating to steam then you would use large amounts of energy.

Tony

[James Dubendorf]

Eric,

In my experience, cooking with basic just add water freeze dried meals doesn't require nearly that degree of precision (as long, that is, as you are not relying on boiling to treat your water). I do find that bringing my water near to but not at boil is more than adequate, especially with a coozie, and does save fuel (sitting around waiting for food to cool is an indication of wasted fuel). And, I mentioned above, cooking to a certain fuel usage rather than to a certain water temperature is a shift in mentality that can help you regulate fuel over the course of a trip. Just my two cents!

James

[Michael Matiasek]

Does anyone have any recommendations for fuel estimates when melting snow? I am considering the primus ETA pack lite, since it received a good review in the winter stove and heat exchanger stove reviews. Perhaps there are other forum threads that I have missed on this very topic? thanks for your help.

Mike

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