FAQ - Efficiency - technical details

A Review of Stove Weights, Fuel Weights and Fuel Efficiencies
Send comments and corrections to the maintainer Roger Caffin

People argue at great length about which stove is best, or lightest, or whatever. Rarely do they put the argument into it's proper context: the full weight in your pack for the trip you are doing. For that matter, some people get very excited about whether the fuel for the stove for the trip will cost $1 or $2 - when they have spent $40 (2005: make that $80!) on petrol for the car to get to the start of the trip. Strange, and misguided imho. So, let us explore weights and efficiencies and costs. This is a technical page with lots of tables of numbers and few pictures. Sorry about that.


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Among some walkers in America there is a great fascination with alcohol stoves at present. Granted, the Pepsi Stove is extremely light (10 grams!), but this is not the full story. You also have to look at the weight of the fuel used and a whole lot of other factors if you want to be serious about minimising your total pack weight. You should also consider how easy it is to cook dinner: you're there for fun after all. This brings into play the amount of cooking you do and the energy efficiency of the fuel. If you are just doing a one night trip from home we can assume there are no problems in organising your fuel, but on longer trips you must consider how you are going to refuel. In some countries you must even consider what fuels are available. (In Nepal for instance you have kero, kero and kero.) So you end up having to do a balancing act between all these factors:

I cannot predict how much fuel you will use: I can only tell you how much I use cooking for two people (my wife and myself). In this context, our typical daily menu is like this:

Your meals will differ, but all things scale to some extent and my figures are the only ones I have, so let's assume my figures are representative. You will note that we do not do any extended "cooking": most of our food is freeze-dried and requires only a minute of boiling, plus some Dutch-oven* treatment. We don't do any frying either. (Makes washing up very easy.) Regional variations will happen of course: in France we had to eat an awful lot of fresh French bread and local Brie cheese, washed down with coffee. My wife had tea and croissants for breakfast. Life was so hard ...

* Dutch Oven: a neat trick for cooking your food. The name derives from a Dutch practice I believe. Bring the food to the boil for about 15-30 seconds, with a lid on the pot. Then turn off the stove and keep the pot hot (lid ON) with some sort of insulation around it. I sometimes use my hat, but a shiny pot out of the wind actually loses very little heat by radiation. Leave for about 10-15 minutes. The food will probably cook almost as well as if it was boiling, but you use no fuel in this time and have no risk of burning the dinner either. This works well with most foods (pasta, dehy, etc), although some forms of rice can be a bit stubborn. You might be surprised just how much water gets absorbed in the process.


Fuel Usage

We want to know how much fuel we will need for this menu for two persons, but this will depend on the fuel being used. The figures given here come from many years of extensive trips with many stoves, for the general sort of menu given above. The names of various fuels depend on the country: I have tried to give some fairly general equivalents for international readers. I have not included diesel or heating oil for reasons given in a previous page.

Fuel Mass per day
Shellite (Coleman fuel, etc) 50-60 gm
Kerosene, (jet A1 fuel) 50-60 gm
Gas (butane/propane mix) 30 gm
Gas (in the snow) <40 gm
Methylated spirits (alcohol) 80-100 gm
Solid fuel (Hexamine) tablets ~80+ gm

I have listed typical fuel usage here for two people. See under Tricks for how to reduce this even further. The figures given here are reasonably conservative. I emphasise that the gas consumption figure is based on a lot of nights and a lot of trips, including 6 and 8 week trips across the Pyrenees.

You can immediately see that what fuel you use will have a significant influence on how much fuel you need to carry. Why are there these differences? It is partly because the energy you can get from each fuel depends very much on the molecular structure of that fuel. This is shown in the next section. More explanation of the physics is given in the Technical Notes under the table.

However, there is more to it than just the efficiency of the fuel. When you use a petrol or kero stove you have to prime it. This takes time and fuel. Sometimes you also have to let it warm up - this too takes fuel. There is also a very strong temptation to just leave it running even while you are not actually using it, and this uses yet more fuel. Many walkers have commented on this.

The figures given above are typical values for cooking for two people in a fairly relaxed manner. However, if you want to go lightweight, there are ways of reducing the fuel weight. I have listed some of these on the Stoves - Technical details page. There are of course other ways of reducing fuel consumption for the ultra-lightweight enthusiast: use a miniature metho stove, abandon the stove completely and use a wood fire, or eat cold food. The latter is an unpleasant thought.

Safety Note: Never use genuine petrol in a stove. The refinery adds a number of quite nasty things to it to make cars run better: these are not good for your health. Things like lead (brain damage), benzene (serious carcinogen) and other more esoteric things. The term 'petrol' is used here solely as a generic. Use fuels such as Shellite, Coleman Fuel and other similar fuels sold by stove manufacturers. In addition, some of the additives gum up the stove and block the jet.


Stove Operation Times

Another question often asked is how is how fast a stove works: how fast can a stove boil a litre of water? This seems to be a favourite machismo "feature" of some of the stove manufacturers. Well, fair question, but you shouldn't place much emphasis on it. You might want a reasonable speed when making a cup of tea, but 30 seconds here or there simply don't matter. Enjoy the view. Of equal importance is the time it takes to set the stove up and get it going, and whether you can turn it down to a simmer nicely. Most of the figures here come from the manufacturers or vendors, so treat them all with caution anyhow.

Most of the times are pretty rough: should we measure the Set-up time in summer or when your hands are frozen? Lighting time reflects the amount of priming needed: practice makes perfect of course. I was going to include "Tank time" or how long a "tank" lasts, but this really only concerns the metho stoves, which have very small tanks. Anyhow, how do you measure it? Do you have the stove on roar or simmer? Do you have a small or large tank or gas cartridge attached? If you think I have a figure wrong, please tell me.
Fuel Stove Set-up time Lighting time Boiling time
Metho Trangia 2 min 1 min 9 min *
Metho Home brew (big!) 1.5 min 1 min 3.5 min *
Metho Home brew (small) 1.5 min 0.5 - 1 min 15+ min *
Shellite Coleman Feather 4422 min0.5 min 4 min
Shellite Coleman Peak Apex2 min0.5 min 3.5 min
Shellite MSR Whisperlite2 min0.5 min 3.5 min
Shellite MSR XGK2 min0.5 min 3.5 min
Shellite Optimus 8R1 min1 min 10 min
Shellite Primus Multifuel2 min3 min 3.5 min
Shellite Primus Varifuel2 min3 min 3.5 min
Kero MSR Whisperlite2 min3 min 3.5 min
Kero MSR XGK2 min3 min 3.5 min
Kero Coleman Peak Apex2 min3 min 3.5 min
Kero Primus Multifuel2 min3 min 3.5 min
Kero Primus Varifuel2 min3 min 3.5 min
Gas Snow Peak Titanium1 min4 sec 4 min
Gas Snow Peak GS-200D1 min4 sec 5 min
Gas Coleman Pocket1 min4 sec 3.5 min
Gas Coleman Backpack1 min5 sec 3.5 min
Gas Coleman Max Extreme1 min6 sec 3.5 min
Gas Camping Gaz Twister1 min4 sec 3.5 min
Gas Camping Gaz Twister Piezo1 min1 sec 3.5 min
Gas MSR Pocket Rocket1 min4 sec 3.5 min
Gas MSR Rapidfire1 min4 sec 3.5 min
Gas Primus Yellowstone1 min4 sec 3.5 min
Gas Primus Multifuel1 min4 sec 3.5 min
Gas Primus Titanium1 min4 sec 3.5 min
Gas Trekker (typ)1 min4 sec 8 min **
Gas Trekker modified1 min4 sec 3 min **
Gas Caribee (typ)1 min4 sec 3.5 min

* The metho stoves have a very little tank which does need refilling frequently. The big problem is that you usually have to let the stove burn out and cool right down before you do refill it. This time is not included. Some home made versions are larger, heat faster but eat metho faster, while some are very light but deathly slow.
** The Trekker gas stoves have small holes in the burner. These seriously limit the gas flow so it boils water more slowly; conversely it can simmer at an extremely low level, which is useful. As an experiment, I modified a Trekker burner by drilling all the holes slightly larger (needs a mill to do it properly) and this made it run even faster than an expensive bushwalking stove. This completely voided any warranty of course.


Fuel Physics

The table below represents the best information I have been able to find about the various fuels we use. If you have better information, I would appreciate a copy. The column 'HPI' is for 'Heating Power Index: a measure of efficiency found in some Primus literature, but whether it relates to fuel by volume or mass I am not sure. Mass is more likely.

Fuel Density gm/ml No. C atoms HPI Boiling Point C Energy kcal/gm Energy kcal/ml Energy MJ/gm Energy MJ/ml gm to boil 1L ml to boil 1L
Propane 0.51 3 101 -42.1C 12.0 6.1 0.050 0.026 7.54 14.5
Isobutane 0.57 4 99? -12C ~11.8 6.7 0.049 0.028 7.69 13.5
Butane 0.59 4 99 -0.5C 11.8 7.0 0.049 0.029 7.69 13.0
Butane/Propane mix 0.57 3/4 100 varies 11.9 6.8 0.050 0.028 7.54 13.5
Petrol 0.70 4-12 86 45 - 128 10.2 6.8 0.043 0.028 8.77 13.5
Kerosene 0.80 11-16 85 160 - 260 10.1 8.3 0.042 0.035 8.98 10.8
Diesel 0.84 13-18? 82 180 - 340 9.8 8.7 0.041 0.036 9.20 10.5
Charcoal 0.8 na 71 na 8.4 na 0.035 na ? na
Methylated Spirits 0.79 2 53 +78 6.3 5.0 0.026 0.021 14.5 18
Hexamine 1.284 ? ? na 7.4 9.5 0.031 0.040 ~20 ~26
Dry Wood 0.9 na 34 na 4 na 0.017 na ? na


Technical Notes on Fuels

Some explanation and comment on the above data will help understand what is going on. Herewith some thoughts: contributions would be appreciated.


Fuel Quantities for Trips

Let us consider a 5 night trip for two: a nice intermediate value. For this we need to build a table as follows. If it doesn't include your favourite stove, my apologies. Note this does not include the weight of a stove base or a windshield: I will assume these would be much the same for all. Neither does it include spare fuel for melting snow. All weights are in grams: what matters are the relative values. I have deliberately biased this table against gas by allowing a partial fill of a petrol/kero bottle but insisting on taking a new, full gas cartridge. The Snow Peak and Coleman Xtreme cases are given for two different cartridge sizes as a matter of interest.

Stove Stove wt   Fuel   Fuel wt Fuel bottle Bottle wt ~Total %dead
Coleman Peak 1 Apex 500 petrol 250 MSR 11 oz 118 868 32%
Coleman Peak 1 Apex 500 kero 250 MSR 11 oz 118 868 32%
Whisperlite Int'l 407 petrol 250 MSR 11 oz 118 775 32%
Whisperlite Int'l 407 kero 250 MSR 11 oz 118 775 32%
Snow Peak GST-100 75 but/pro 200 (Primus) 120 395 37%
Snow Peak GST-100 75 but/pro 450 (Primus) 140 (665) 24%
Primus 3273 95 but/pro 200 (Primus) 120 410 35%
Coleman Xtreme 313 but/pro 170 Powermax 68 581 29%
Coleman Xtreme 313 but/pro 300 Powermax 86 (699) 22%
Cheap steel gas burner 200 but/pro 200 (Primus) 120 515 35%
Trangia (mini) 160 alcohol 400 Nalgene 80 680 17%
Pepsi Stove 20 alcohol 400 Nalgene 80 490 17%
Hexamine 85 tablets 420 none 0 505 0%

These figures have all sorts of hidden factors built in. These include:

If you are going into the snow you will need to add a bit of fuel just to handle the cold weather: the water starts colder and you may want more hot drinks. After all, you are there for fun. You should also allow for fuel for melting snow. We usually add about 25 - 50% for that, but the amount will depend on the country we are in. It doesn't get all that cold in Australia, so we can usually find water somewhere in the snow. Don't bother looking for water in the Antarctic!)

For those who have never met the Pepsi Stove, a few words of explanation. You take two aluminium soft drink cans, cut them up and stick them together to make a sort of copy of the Trangia burner. The unit is 'closed' except for the filling hole (which may or may not get closed) and the jets. The metho gets hot and the vapour pours out the jets, as with a Trangia. Obviously you don't count the cost of the soft drink cans, but the metal-loaded epoxy used to glue the bits together is expensive. The result is still very cheap and light, but you need some sort of pot support around it, and I haven't counted the weight of that. The unit holds just so much metho, burns it all up, and then has to cool down before you can refuel it. If you put too much fuel in, you have to let it burn away. If you don't put in quite enough, you have to wait until the stove cools before you can refuel and finish cooking dinner. Once they get going some of them pour out the heat, far more than the little beercan cooking pots can absorb in most cases. Simmer? Forget it. They have a fanatical following in America among people who have never looked at the weight of the fuel, and who do all their cooking by pouring boiling water over ... something.

Now let's consider the requirements for two weeks and see what happens. If you are planning even longer trips, just scale from here. I have cut out two of the combinations as they don't add anything and increased the size of the liquid fuel bottle. I have also assumed the larger gas cartridges as they are more weight efficient (see above). The 450 g cartridge does raise the height of the cooking pot, making the assembly less stable, but we had no trouble in the Pyrenees with the combination as long as we used a small plywood stove base. We found the larger gas cartridge lasted 2 weeks just nicely; we used up three in the 6 weeks.

Stove Stove wt Fuel Fuel wt Fuel bottle Bottle wt ~Total
Coleman Peak 1 Apex 500 kero 650 MSR 22 oz 130 1280
Whisperlite Int'l 407 petrol 600 MSR 22 oz 130 1137
Snow Peak GST-100 75 but/pro 450 (Primus) 140 664
Primus 3273 95 but/pro 450 (Primus) 140 685
Coleman Max Expedition 313 but/pro 450 Max 150 913
Cheap steel gas burner 200 but/pro 450 (Primus) 140 790
Trangia (mini) 200? alcohol 1000 Nalgene 200 1400
Pepsi Stove 10 alcohol 1000 Nalgene 200 1210
Hexamine 85 tablets 1180 none 0 1265

In addition, I have reduced the weight of fuel required per day slightly and by various amounts. These reductions are based on actual experience with very long trips: one gets a little more efficient with time.


Fuel and Stoves Costs

Sadly, every cooking method costs - unless you are going to use a small wood fire. The cost of using a stove consists of the initial (stove) cost and the cost of running the stove (the fuel). Let us first look at the cost of the fuel. These costs are in Australian dollars, and they are very approximate, but hopefully they will do. I have quoted for Shellite rather than straight petrol: the latter is not healthy owing to the additives. I assume cooking for two people.

Fuel Fuel for 5 days Cost for 5 days
Shellite 250 gm $1
Kerosene, (jet fuel) 250 gm $1
Gas 200 gm $7
Methylated spirits 400 gm $1
Hexamine 420 gm $31

One immediately sees that the gas cartridge is dearer than the liquid fuels, if that's all you are counting. You can blame this on the packaging. (And the hexamine is way over the top for fuel alone, but almost zero cost for the stove.) However, this fuel is going to cook for you for 5 days: is it that dear? How much did your food cost? How much did the rest of your gear cost? And just how much did you spend getting to the start of the trip by car, plane or whatever?

Now let's look at the cost of the stoves and the total cost of cooking for, say, 30 nights. I have picked that number of nights as being reasonable for many keen but not fanatical walkers for a year. Doubtless you will be different. In economics terms, this amounts to writing off the total cost of the stove over one year. Normally a stove should last for many years, so this is harsh. Again, figures are very rough, and if you can update them it would be appreciated. For the cheap steel gas stove I have assumed the cheaper larger cartridges.

Stove Stove cost Fuel quantity Fuel cost ~Total
Coleman Peak 1 Apex $150 1.5 litres $6 $156
Whisperlite Int'l $150 1.5 litres $6 $156
Snow Peak GST-100 $240 6 cartridges $42 $282
Primus 3273 $60 6 cartridges $42 $102
Coleman Max Xpedition $160 4 Max cart $42 $202
Cheap steel gas burner $40 2 lg cart $20 $60
Trangia (mini) $100 2.5 litres $8 $108
Pepsi Stove $10 2.5 litres $8 $18
Hexamine $6 180 tabs $156 $156

Where does this leave us financially? Clearly the Pepsi Stove is the cheapest over all, even if it uses so much fuel (unless the Hexamine stove can beat it). But coming a very close second are the cheaper small gas stoves. If you want the absolutely lightest gas stove (the Snow Peak) you have to pay lots for it. Why it has to be so dear is not obvious: one suspects local marketing may have something to do with it. You can buy it via the web much cheaper than in an Australian shop: I am sure I have seen US$90 quoted. But if you go up just a fraction in weight the cost of a gas stove becomes very reasonable. Considering the cost of all the rest of the backpacking gear, it is not particularly significant.



There is always the problem of getting more fuel. With petrol you can probably buy any amount you want at a service station - if you can find one. Walking the length of the GR11 in Spain for six weeks I think we saw two service stations; in Wollemi or Kosci we wouldn't see any. With kerosene and alcohol you would normally be limited to buying a full bottle in a hardware store: probably a litre at a time. That is going to weigh about 800 grams. The standard butane/propane cartridges weigh 330 or 590 grams each.

We have in the past cached kerosene in 1.25 litre PET bottle: large soft drink bottles with the rocket bases. We did this where we cached food supplies, but not in the same container. I would be reluctant to trust a PET bottle with petrol because of the higher vapour pressure in the sun. For similar reasons I would not be willing to carry kerosene in a PET bottle inside my pack: the risks of damage or even just leaks seems too high. You have to experience fuel-soaked food to know how bad it is. You could of course cache supplies in more robust bottles.

On our trip in Spain we did have to buy gas cartridges. Shopping was an 'interesting' exercise in itself there, even entertaining, but it turned out to be easier to buy a gas cartridge than any other form of fuel. Little towns with a general store were likely to carry gas, even if the town didn't have a petrol station. But, different places, different conditions.



For a short trip of 5 nights the lightest stove path (so far) is a small cheap gas stove. It can also be nearly the cheapest: just slightly dearer than the fabled Pepsi Stove. The petrol and kero stoves seem to be both heavier and dearer than most of the rest. But for a longer trip of 14 nights the alcohol stoves are at the heavy end of the weight range. Why is this so? Because the fuel is so very inefficient and heavy. Reducing the weight of the stove to zero cannot overcome the fuel weight penalty.

I have to add that small wood-burning stoves will turn out very light on long trips, as long as you can find fuel and it is safe to light a fire. Coming close behind that would be the solid fuel method: Esbit or Hexamine tablets. Some through-hikers on American trails use these as they can get the fuel in many places or post the fuel to the regular small town post offices along the way. However, neither of these are as convenient; neither is really safe to use in a tent, both make the pot dirty and neither is all that great in the snow.

One could add that the gas stoves are incredibly easy and convenient to operate (which contributes to the small amount of fuel they need), while the alcohol stoves seem very tricky and of such limited functionality. The petrol and kero stoves remain heavy and expensive, but the incremental cost of fuel is low. In some places like Nepal kero is the only fuel available of course. The hexamine stoves are very small and light, but are not very convenient to use, and the cost starts to rise very fast over time. I have seen very variable test results for just how hot one tablet can heat some water: certainly you must use a windscreen with them.

Which stove you pick is up to you. You could do what some of us have done: buy one of each and run your own tests! If you do, I would love to hear the results. The Pepsi Stove family is very cute, but they certainly are not the best ultra-lightweight solution for trips of any length unless you can buy small quantities of metho along the way.