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

[Cat Jasins]

Companion forum thread to:

Comparative Fuel Efficiency and Carry Weight for Six Lightweight Backpacking Cooking Systems: Part I Assembling Comparable Cooking Systems and Test Data

[Summit CO]

OK I’m gonna have to pony up and become a member…

Is there any numbers on how efficiency is affected by pot shape (tall skinny mugs/beer cans vs wider pots/pans of equal volume) or composition (Ti doesn’t conduct as well as Al)?

[Will Rietveld]

Good questions. The short answer is there is lots of discussion on this forum and elsewhere on the effects of pot shape, metal conductivity, windscreen design, etc . A really interesting new windscreen design is the Caldera by TrailDesigns; check it out at http://www.traildesigns.com/products01.html. Roger Caffin and I will be trying their new windscreen systems out in the field and will have some comments/analysis on them later on.

Cheers!
Will

[Anthony Dohrman]

Part 2 is here: https://backpackinglight.com/comparative_fuel_efficiency_and_weight_of_stoves_pt2/

[Ken Thompson]

Part 2

https://backpackinglight.com/comparative_fuel_efficiency_and_weight_of_stoves_pt2/

https://backpackinglight.com/forums/topic/3507/

[Jon Fong / Flat Cat Gear]

After reading this article, there are a couple of statements that do not quite make sense to me.  According to the data regarding isobutene; integrated stoves have the highest efficiency followed by canister top (29% -33% higher) with remote stoves being the worst of this class (~50% higher).  While I don’t have an integrated stove, testing the latter 2 configurations I have found consumption can be in the 5-6 gram range (YMMV).  The key to fuel efficiency to understand how your stove works with your pot/mug/windscreen.

What really jumps out is the comparison of white gas stoves (11 grams per pint).  This number seems to be off to be.

Finally, there is a comment about alcohol stove performance dropping off in the Highlands.   I am going to assume that this is because of the particular stove that you selected (as well as windscreen).  I have done substantial testing in the area and have not found this to be the case (with our stove designs anyway)

My 2 cents

[Ken Thompson]

We know more twelve years later

 

[James Marco]

Yes, as far as stove use goes, isobutane, WG/Diesel are within fractions of each other.
The actual fuels are quite similar: About 19700BTU/lb for butane, and about 19300BTU/lb for WG. There is no way his figures can be correct for WG using about 11gm/16oz and canister gas giving about 7gm/16oz (roughly 50% more WG for the same heat.)

[Roger Caffin]

All those fuels are long-chain hydrocarbons, although the exact carbon/hydrogen ratio varies a bit. That does not really matter much because most of the weight is in the carbon atoms, and they also give most of the energy. So IN THEORY (and in the lab) the fuels will behave fairly similarly.

That’s in the lab; in the field it is a very different matter. Lighting a canister stove takes a couple of seconds and you are cooking immediately. When you take the pot off the stove good practice is to turn the stove off. However, with liquid fuel stoves life is much harder, and especially with kero. Priming the stove and getting it hot enough for the fuel to vaporise takes time and fuel, and you are not cooking in that time. Then when you have finished cooking one thing the temptation is to leave the stove running, albeit at low power, until you are ready to cook the next thing, to avoid the hassles of priming and starting.

In practical terms, in the field, you can be using anywhere from an extra 50% to an extra 100% of liquid fuel for the same amount of cooking. Been there, measured the fuel consumption.

Cheers

[James Marco]

While I have been using the remote canister stove for up to two weeks out at a time, the savings are basically only in the actual stove. The SVEA goes about 17oz, not counting the cup and windscreen. No pump, no long fuel tubes to empty, and fairly quick to prime (it takes just about a gram or two to warm it up to operating temp.) It gets only about a gram or two less efficient for boiling 500ml (~1pt.) Of course, most of this depends on the wind screen/pot set up, ambient temps, and, of course, your overall techniques. Any extra fuel usage would be due to priming. And, I have use for WG besides fuel on the trail. It can remove sap, etc from your hands, gear and cloths. It can dilute DEET as needed. In a pinch, it makes a good fire starter on a tight bundle of tinder, and so on.

I agree, I would not use diesel (kero) if possible to avoid. It takes a LOT to heat these up. I would guess it takes close to 5gm of fuel just to get the things to operate. Other WG stoves, are often in the same category and have tubing/pumps, and take 3-7gm just to get them to go. The XGK, and the SimmerLight both burn overly hot for solo use, resulting in a LOT of wasted fuel. Sort’a like burning a canister on high all the time.

[Nick Gatel]

While I have been using the remote canister stove for up to two weeks out at a time, the savings are basically only in the actual stove. The SVEA goes about 17oz, not counting the cup and windscreen. No pump, no long fuel tubes to empty, and fairly quick to prime (it takes just about a gram or two to warm it up to operating temp.) It gets only about a gram or two less efficient for boiling 500ml (~1pt.) Of course, most of this depends on the wind screen/pot set up, ambient temps, and, of course, your overall techniques. Any extra fuel usage would be due to priming.

How much fuel use for priming? Very little as you stated. What I typically do is to burn a few scraps of paper from my consumed snacks and hold the stove over the flames to build pressure in the tank. Sometimes I will hold a lighter under the tank for a few seconds to build up pressure. Then I open the valve, a few drops of fuel will dribble down into the priming bowl, I turn off the valve and light the fuel. Just before the fuel completely burns and if I time it right, I open the valve and light the fuel at the burner — it takes just a few seconds to get to operational mode.

Sometimes I take a little plastic straw, stick it into the tank and then place my finger over the top of the straw, then place the straw over the priming bowl and remove my finger from the top of the straw to fill the priming bowl, close the valve and light the priming bowl.

I have two 123 stoves, not the “R” model and have been using them for 45 years or so. So what is my dollar cost average per year of the purchase, given the stoves cost something like $12.50 in 1971? Twenty-eight cents per year without adjustments for inflation. If we take inflation into consideration, $12.50 in 1971 is about $77 in 2018. How much does a Caffin stove cost? IIFC around $150 or more. Too expensive! Will it last 45 years of use? I don’t know, but I suspect it won’t. I’ll keep my Svea stoves and continue using them until I die and then bequeath them in my will to my kids.

Once I retired, I did an analysis on fuel cost per day. Alcohol and liquid gas win by a huge margin. I use alcohol most of the time but still often take my Svea, especially on longer trips in cooler weather so I can have a hot drink several times during the day and evening. Can I afford the more expensive fuel? Sure, but when I show my wife how much money I am saving I was hoping she would stop buying so many pairs of shoes… that didn’t work :-(

 

Here’s the article.

[Jon Fong / Flat Cat Gear]

Old School rocks!

 

[David Thomas]

”What I typically do is to burn a few scraps of paper from my consumed snacks and hold the stove over the flames to build pressure in the tank.”

I just light farts to pre-heat the tank, thereby allowing me to burn paper scraps sooner and save literally hundreds of gram-meters (they’re like pound-miles, but much smaller for serious ULers).

[David Thomas]

Gun nuts aficionados sometimes say “Beware the man with one gun” because, presumably, he will be very adept with the only weapon he ever trains with.  I think about that as I rotate between stoves for different trips – usually upright canister stoves, but sometimes a remote canister stove for its lower profile on a large group trip when I use larger pots, alcohol when I can’t get/ship canisters to a remote location, and sometimes even propane for snow camping because vapor pressure matters more than water when you’re pulling a sled across a frozen lake.  Then there’s Manfred with his alcohol set-up or Nick with his SVEA-123 and they have it all dialed in.  Exactly how much fuel to pack, how much to use for each meal, and how to start the stove as efficiently as possible.  The other arena I consider that concept in is tents: I pick a tent for a particular trip, but I’m sure that a thru-hiker coming off the PCT is far better at utilizing their Z-Packs Duplex than I am with any particular tent I have.

I agree with Roger’s summation of the inefficiencies of WG stoves and they match my experience even when I was regularly using MSR WhisperLite.  It still took some fuel to light it and I tended to leave it running on low to avoid restarting it later.  So it took me a decade too long to switch over, but now I find the lack of any possible smelly fuel leak and that I let my kids do more unsupervised cooking with a canister stove to be additional advantages.

[Bruce Tolley]

@ Nick

What about the cost of all that elbow grease since 1971 used to keep the brass on the Svea 123 nice and shiny?

I polished mine up and presented it to my son right before his first backpacking trip.  He declined it as an antique and ended up with a isobutane burner.

[Nick Gatel]

What about the cost of all that elbow grease since 1971 used to keep the brass on the Svea 123 nice and shiny?

Good point. I’ve only thoroughly cleaned and polished the stoves once, about 10 years ago. Also replaced the wick and cap gasket (I found a bunch of Viton gaskets on eBay for really cheap). The graphite packing is still good in both stoves.

[Roger Caffin]

re priming: getting a WG stove going in warm/hot weather is miles easier than kero. Some WG even contains iso-butane.

Cheers

[James Marco]

I have been using the old 123 for over 45 years. Yeah, it is fairly well dialed in.

WG is a mixture of a lot of different stuff, mostly heptane, hexane, pentane and some other stuff in the ene family (and even a bit of octane.) I believe that the original fuel had no additives which is what gave auto gas the colors (depending on the additive & dye.) Anyway, this is why it was called “white” gas according to an old mechanic I had the pleasure of working for back in my teen years. But it was and is just a fractionated, low volatility fuel. They don’t bother cleaning it up much (except to remove benzine and other highly carcinogenic compounds I believe, but they may skip this since it will just be burned) nor are they that accurate with temps/filtering during distillation. What dissolves in usually stays in. So, it likely does have some butane, isobutane, and stuff we normally think of as gasses.

[Roger Caffin]

Old (1960s?) advertising jingle (in Oz) for some brand of petrol or other:
“It’s got butane, iso-pentane and toluol too”
I assume there was some truth behind this.

Cheers

[Nick Gatel]

WG is a mixture of a lot of different stuff, mostly heptane, hexane, pentane and some other stuff in the ene family (and even a bit of octane.) I believe that the original fuel had no additives which is what gave auto gas the colors (depending on the additive & dye.) Anyway, this is why it was called “white” gas according to an old mechanic I had the pleasure of working for back in my teen years. But it was and is just a fractionated, low volatility fuel. They don’t bother cleaning it up much (except to remove benzine and other highly carcinogenic compounds I believe, but they may skip this since it will just be burned) nor are they that accurate with temps/filtering during distillation. What dissolves in usually stays in. So, it likely does have some butane, isobutane, and stuff we normally think of as gasses.

When I was young I used to sell WG where I worked both in gallon cans and in bulk for 35 cents a gallon! It was branded as Chevron Blazo fuel. From what I remember it was gasoline without the additives and the benzene was removed. Back in those days all gasoline for motor fuels contained lead compounds to help with ignition and engine performance, but that gasoline would foul up stoves. Today you can use motor gasoline (not as well as WG) in many liquid stoves. IIRC, White gas had a very low octane rating around 50. Today regular unleaded has an octane rating of 87, although that number is calculated differently than in the good ol’ leaded days.

Here’s a link to the 1987 MSDS for Chevron Blazo fuel

http://www.hazard.com/msds/f2/bbr/bbrcy.html

 

[James Marco]

Hey, ha, I remember gas being available for 27.9C/a gallon as I pumped it…. $5 was a lot of gasoline!
Yeah, Blazo worked good but burned relatively fast compared with Coleman fuel. In a pinch, you can use toluene as a fuel in a Svea, but it burns very hot and overheats easily. This works well for very low heat outputs and still maintains pressure in the stove. Or in winter. I sometimes added a pint of toluene with a gallon of white gas in my 2 gallon mower can. Then pour it back in the bottles for use. You can also mix <10% ethanol or methanol for improved heat/combustion characteristics in summer and/or to stretch your fuel supply. I might be wrong, but I think the biggest octane boost to unleaded fuels comes from the addition of 10% alcohol, slowing the combustion rate down in the engine without changing carburation at all.

[Rex Sanders]

Used a “self-cleaning” Svea 123 for several years on leaded regular gas – it worked, I didn’t know any better, and it was cheap and readily available for resupply. Ever try pumping gas-station gasoline into a Sigg fuel bottle? Messy.

As a teenaged gas station attendant, pumped a lot of $0.259 per gallon gas during “gas wars.” Until I learned to recognize them, got showered with leaded gasoline by a few cars that “burped” if you pumped too fast.

Which probably explains a lot. Some parts of the good old days weren’t so great.

— Rex

[James Marco]

Rex, yeah, you can run the 123r on unleaded fuel. Even the old stuff only required extra cleaning. But, it doesn’t burn real hot, nor, real clean. Hard to hold a low flame that doesn’t produce a lot of soot and hard to get going. I have tried to pump into a SIGG bottle. Worse, is the “coke” bottles I later switched to. Notice I said “tried.”

I remember “gas” wars. We were told to pump as much as possible in every car. Overfull, ya know? Ha, hey, yup, I always went home smelling of fuel. I believe the owner was b!tching about the gas actually loosing money, but adding oil (whether the car needed a full quart or not,) air inflations (selling tires, patches and valve repair kits,) wipers and so on made up for all of it… We eventually opened a gas station when I was 17 and I worked every weekend, all weekend, sleeping in the storeroom for 24 hour service when it wasn’t busy. We would sell quite a bit between 0100 and 0400 on Friday and Saturday. All the bar rooms would close at 0200 and everyone would get gas on the way home. We also had a trucking company that would fill up the fleet for a nickle discount per gallon, at 40 gallons per tank on the bigger trucks…they had 4. Everybody was happy…

[David Thomas]

“I believe that the original fuel had no additives which is what gave auto gas the colors (depending on the additive & dye.)”

Tetra-ethyl lead has a yellowish color to it.  It was first used as a dye in some General Motors research engines to watch its passage through the fuel system and they found that the engines knocked less at high compression when TEL was used.  That was patented by GM and ESSO and they formed the Ethyl Corporation to market TEL as a fuel additive.  TEL is yellow-colored and gave leaded gasoline a yellow tint which was later enhanced with additional yellow dye, partly for marketing purposes.

Mid-grade unleaded motor gasoline was dyed pink to (originally) avoid confusion with leaded gasoline.  I’ve pumped some (60,000 gallons) of spilled gasoline from off of the groundwater that was so fresh that it still had that pink color to it.  I put 8 gallons in my Toyota Corolla and it drove fine.

By the late 1990s, with no leaded motor fuel in use anymore, states began dropping their requirements to dye motor gasoline.

The four grades of aviation gasoline each have their own dyes both because of their taxation and, more so, to be able to confirm the proper fuel is in the airplane’s tanks.

So, yes, un-dyed / un-taxed gasoline was called “white” or “clear” to distinguish it from dyed varieties.

It’s the reverse for diesel: un-taxed diesel fuel is dyed red and is legal to use in heating and farm equipment but not in motor vehicles on public roads.

[David Thomas]

If you want motor gasoline from the filling station to be lower volatility like white gas, just leave it out in a shallow container for while.  The C4, and C5 compounds will evaporate more quickly than the C6-C10, less-volatile components.  Or do it in a taller container by bubbling air through it.  But if bubbling with something like an electric fish-tank bubbler, place any electrical equipment well off the ground (>18″) so as not to ignite the heavy gasoline fumes.  Also, it’s good practice to place such equipment and yourself on the upwind side.

Any HDPE container is gasoline-safe and although 1-gallon milk jugs are HDPE, they’re pretty thin.  I prefer 1-gallon washer-fluid containers because they’re thicker walled but still translucent.  Rinse the container and dry throughly.  Mark the side of the container with the original fuel level and when it’s dropped 10%-20%, you’ll have removed a majority of the most volatile compounds.

[Author]

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