Fuel for long distance trips

[Quixoticgeek]

Am getting into planning and plotting thoughts for a couple of remote trips. Now given the peculiarities of the locale (not going into specifics), I can't rely on biomass for stove fuel.

So I find myself pondering the two obvious liquid fuel options that are available: Meths and Petrol. Now the petrol stove is 150g heavier than the meths stove. But, if my understanding is correct petrol has a higher energy density, meaning you need less of it for a given amount of heating. The question I've got is this: How long would I have to go between refuelling opportunities for the extra weight of the petrol stove to be off set by the higher energy density of the petrol?

I am also wondering if the controllability of the petrol stove - you can turn it off the moment that the water is boiled -offers a significant enough efficiency saving over a meths stove that you can't turn off but instead have to let burn out, to justify the weight of the petrol stove on longer trips.

Has anyone else done the maths on this one?

Thanks

Julia

PS Wasn't sure where was the best place to put this thread, if I've got it wrong, apologies.

 

[Toddy]

Have you seen the little pop can stoves ? they weigh virtually nothing and they'll boil a mug of water on a couple of teaspoonsful of meths. If you juggle your food with forethought, it might do very well. Weighs pretty much nothing too.

cheers,
M

 

[Teepee]

There's too many variables on this to give an accurate answer J. It all depends on your personal usage.

Alcohol then hexy tabs are the lightest for a 4-10 day trip. Canister mounted gas then takes front seat. Petrol is never the lightweight option.

If you want hard figures for specifics, Backpackinglight.com has it all there in spades for fuel usage.

One thing to bear in mind is that an alcohol/hexy setup weighs hardly anything when all the fuel has gone.

 

[Idleknight]

With some of the meth's stoves you can put the lid back on (make sure to remove any rubber rings) this puts out the flame and you can then use the meth's later.
There are some tricks for the other stoves as well like covering them with a cup. It saves on lost fuel.

Is resupply a factor? As Meth's is easier to get in the right amounts, you don't need a large approved container if you get petrol from a petrol station.

 

[Quixoticgeek]

Have you seen the little pop can stoves ? they weigh virtually nothing and they'll boil a mug of water on a couple of teaspoonsful of meths. If you juggle your food with forethought, it might do very well. Weighs pretty much nothing too.

Yep am aware of them, I don't trust them tho. I have a cat can stove in my brew kit currently, It's a temperamental beast, yes it boils water, but it's durability is poor, it got squashed on a recent trip out, I was able to bend it back largely into shape with my leatherman and at 65p I can just make another one. But if I am 3 days hike from civilisation, I can't just make another cat can stove.

MSR spec says their Whisperlite international will boil 1.3L of water on 1oz of petrol. They are unclear on is that 1oz by weight, or 1 fluid oz of petrol, Which given the Americans propensity for using a unit of weight to measure a volume of liquid, could be anyones guess... If we assume a fluid ounce - 28.3ml, then that is 5.2 cups of water 28.3ml of petrol, or 5.44 ml for 1 cup (250ml) of water... which is half the fuel of the pop can stove you suggest...

Meths is 0.79g/ml and petrol is 0.7g/ml (based on numbers from here). Meaning that at 5.44ml per cup of water for petrol, and 10ml for meths (based on "couple of teaspoons of fuel"), 1L of petrol gets me 183.82 cups of water boiled, or 100 from the meths...

It's around this point the maths makes my head implode... if I get through 4 cups of boiled water a day (for easy maths). A seven day trip is 28L, which is 28 x 5.44 = 152ml for 107g weight. Vs 28 x 10 = 280ml for 221g...

So at a guess, it's at around the 10 day mark then...

What have I forgotten?

J

 

[cranmere]

It depends on a lot of things, not least where you are going and what fuel is likely to be easily available. I lean towards a multi-fuel stove that I can use with petrol, diesel, avgas, white gas etc partly because something of that kind is available darned near all around the world and I've always been able to scrounge something that it will burn in some seriously out of the way places. The stove and fuel bottle are heavier than a meths stove, however if you have something like an Optimus Nova where the fuel bottle is part of the stove system the weight isn't prohibitive. A disadvantage is that if a more complex stove goes wrong you are stuffed, which is why I also take the minimal spares kit and the service spanner.

 

[Toddy]

The lightweight can stove is just a home made version of a trangia burner....and they come with simmer rings that will put out the flame and a screw cap that will save the meths for next time. About a tenner delivered, iirc.

cheers,
Toddy

 

[Quixoticgeek]

There's too many variables on this to give an accurate answer J. It all depends on your personal usage.

Alcohol then hexy tabs are the lightest for a 4-10 day trip. Canister mounted gas then takes front seat. Petrol is never the lightweight option.

If you want hard figures for specifics, Backpackinglight.com has it all there in spades for fuel usage.

One thing to bear in mind is that an alcohol/hexy setup weighs hardly anything when all the fuel has gone.

Hexi is definitely not an option, can't stand the stuff. I've discounted gas canisters for 2 reasons:

1 - I don't like the stability of the canister mounted ones, and those that are connected by a hose offer no real weight saving over a petrol stove,
2 - Finding them in remote locations is not something I really want to risk.

The tare weight for the setup is a concern, obviously the 141g[1] difference between the two has to be carried the full distance of the trip.

Out of interest I wonder how the numbers change as ambient temperature drops?

With some of the meth's stoves you can put the lid back on (make sure to remove any rubber rings) this puts out the flame and you can then use the meth's later.
There are some tricks for the other stoves as well like covering them with a cup. It saves on lost fuel.

Yep, this is true, but those ones are significantly heavier than the ones you can't put the lid back on, if you compare the trangia (which you can) at 120g vs the evernew (which you can't) at 34g... Again, how much fuel would you have to save to justify the extra weight...

Is resupply a factor? As Meth's is easier to get in the right amounts, you don't need a large approved container if you get petrol from a petrol station.

Yes, resupply is the primary reason that gas is discounted along with hexi[2]. For some trips I am doubtful that meths will be available, I am still researching this, and it may be a deciding factor in my choice. Petrol is considerably easier to get hold of, and it's this ease of resupply that is the reason I consider it my primary fuel choice most of the time.

Then I look at these numbers and wonder how much weight we're really talking, and if I would be carrying more than this in mud on my shoes, and thus should just pick the petrol and be done with it...

Julia

[1] Just done the actual maths based on the two stove options I am considering, and it's 141g, not 150g as previously guessed. This works on the assumption that the fuel bottle weights are the same regardless of fuel choice.

[2] Hexi is also discounted for being horrible disgusting stuff in pretty much every regard...

 

[rg598]

Zenstoves has a chart with fuel weights over time that will exactly answer this.

Otherwise, location will govern your fuel choice in most cases. The reason why people climbing in the Himalayas use canister stoves instead of petrol is because petrol is very hard to find there.

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[Quixoticgeek]

It depends on a lot of things, not least where you are going and what fuel is likely to be easily available. I lean towards a multi-fuel stove that I can use with petrol, diesel, avgas, white gas etc partly because something of that kind is available darned near all around the world and I've always been able to scrounge something that it will burn in some seriously out of the way places. The stove and fuel bottle are heavier than a meths stove, however if you have something like an Optimus Nova where the fuel bottle is part of the stove system the weight isn't prohibitive. A disadvantage is that if a more complex stove goes wrong you are stuffed, which is why I also take the minimal spares kit and the service spanner.

I have much the same view. My backpacking/cycle touring stove is either an MSR whisperlite Internationale, or a MSR Dragonfly, the dragonfly will burn everything pretty much, but it does sound like a jet engine. The whisperlite is kerosene or petrol only, but it is a lot quieter (and lighter).

The only reason that the dragonfly is discounted on this trip is again the weight, it's very heavy, relative to the alternatives.

The lightweight can stove is just a home made version of a trangia burner....and they come with simmer rings that will put out the flame and a screw cap that will save the meths for next time. About a tenner delivered, iirc.

Yep, and the trangia and say a titanium pocket stove, comes in at 90g heavier than the evernew titanium set I am using as the meths option or only 51.2g lighter than the petrol option... Which means that the weight saving of petrol over meths happens sooner, and at such a small weight difference, the simple ease of use of the petrol over the meths leans it that way more...

Julia

 

[Toddy]

Petrol's a pain to find in small quantities though. Garages won't sell you a half litre unless you have a container that they approve of. It's not as straight forward as it seems. At least if it's desperate the chemists will sell you meths.
That said, meths doesn't give out as much heat as petrol.
How about the greenheat sachets ? or the chaffing gel fuel ?

I suppose it really comes down to just how much cooking you intend to do. If weight was an issue I think I'd work it out so that a quick boil up was as much as I was prepared to consider.

cheers,
Toddy

 

[Idleknight]

I thought with getting fuel from a petrol station you need to have a approved 5 litre (or bigger) can to put it in. Also there is a minimum buy, which can be 2 Litres. It does vary by petrol station and country, but these two factors can put people off petrol when travelling light.

 

[cranmere]

Petrol's a pain to find in small quantities though. Garages won't sell you a half litre unless you have a container that they approve of. It's not as straight forward as it seems. At least if it's desperate the chemists will sell you meths.

That's true, paradoxically it's often easier in less developed places because they don't have the Health and Safety people breathing down their necks.

 

[Quixoticgeek]

Petrol's a pain to find in small quantities though. Garages won't sell you a half litre unless you have a container that they approve of. It's not as straight forward as it seems. At least if it's desperate the chemists will sell you meths.
That said, meths doesn't give out as much heat as petrol.
How about the greenheat sachets ? or the chaffing gel fuel ?

Yep, had that from a garage in Hereford once, started filling up and they ran out screaming. I showed them the bottle, which was a standard MSR one with it's blurb about being suitable for petrol, and they were happy. Confused the hell out of them.

I've also had fun cycling into a garage in Canterbury with a 25L metal jerry can strapped to the front of my folding bike, started filling up, and again, the running and the screaming. Then they realised I was putting diesel in it and they didn't care. It was to fuel a mini digger I had hired, before anyone wonders what I am planning to cook with 25L of diesel on an MSR Dragonfly stove...

But I digress...

I suppose it really comes down to just how much cooking you intend to do. If weight was an issue I think I'd work it out so that a quick boil up was as much as I was prepared to consider.

Well that is the plan, It will be dehydrated meals that in theory just need boiling up, with maybe the odd LWWF pouch on resupply days when I don't have far to carry it...

Julia

 

[Quixoticgeek]

I thought with getting fuel from a petrol station you need to have a approved 5 litre (or bigger) can to put it in. Also there is a minimum buy, which can be 2 Litres. It does vary by petrol station and country, but these two factors can put people off petrol when travelling light.

Almost. It needs to be an approved container (MSR fuel bottles are approved), and for petrol it cannot exceed 5L for metal containers, and 10L for plastic.

Most say that the minimum dispense is 2L, at every petrol station I've used this has been the case, but I've never had issue filling 1L and 0.33L bottles. It can occasionally mean you have to pay for a full 2L of fuel, but that still tends to work out cheaper than a 500ml bottle of meths most places...

That's true, paradoxically it's often easier in less developed places because they don't have the Health and Safety people breathing down their necks.

Yep. Tho harder to explain what you are doing when you turn up and start filling up this tiny bottle...

J

 

[Frase]

Its maybe no use for you but what I do now when long distance walking is my main stove is a bushbuddy which is a lightweight wood stove and also take with me a whitebox meths stove with maybe enough meths for a couple of days. The wood stove is nice because you never need to worry about running out of wood and through the day you can collect some nice dry twigs.

 

[Macaroon]

[2] Hexi is also discounted for being horrible disgusting stuff in pretty much every regard...

I couldn't agree more - but petrol is equally disgusting, the smell of it every time I wanted a brew or a feed would put me off so much that I'd come back a skeleton!

 

[Quixoticgeek]

Its maybe no use for you but what I do now when long distance walking is my main stove is a bushbuddy which is a lightweight wood stove and also take with me a whitebox meths stove with maybe enough meths for a couple of days. The wood stove is nice because you never need to worry about running out of wood and through the day you can collect some nice dry twigs.

Yep, it's a good approach, and one I will be using in wooded areas on other trips. But it's not going to work for some trips. I'm expecting to go days on end without seeing a tree on some trips.

J

 

[cranmere]

Well that is the plan, It will be dehydrated meals that in theory just need boiling up, with maybe the odd LWWF pouch on resupply days when I don't have far to carry it...

I would experiment with the dehydrated stuff in advance to make sure it rehydrates quickly, some is better than others and half-hydrated stuff isn't very appetising. Sometimes it's worth adding liquid and letting it soak for a while then you don't waste fuel simmering it. I would certainly be working out exactly how much fuel was needed for each boil and measuring the liquid very carefully so as not to waste fuel.

 

[RE8ELD0G]

I vote for a wood stove too.
Mine only weight 158 grams and you can get fuel almost anywhere.

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