Stove Systems for Winter Backpacking

[Ryan Jordan]

Companion forum thread to: Stove Systems for Winter Backpacking

Ryan discusses how you build and utilize your stove system for winter cooking and snow melting to maintain hydration.

[Jon Fong / Flat Cat Gear]

The article is a good general coverage of stove performance in the winter.  Could you please comment on fuel consumption/volume requirements for your top picks?  For snow melting and such, I would image that pack volume starts to become significant.

[Roger Caffin]

fuel consumption/volume requirements
I normally allow 30 g of propane/butane fuel per day for my wife and myself in 3-season conditions. I have had that down to 21 g/day when really, really trying (I had forgotten one canister when packing!).
For winter condition with a remote inverted canister stove I simply double that amount: 60 g/day for the two of us. This is generous. But here in Australia we don’t have to melt snow every night, so we often come home with spare fuel. But, can not rely on that!

It takes as much energy to melt snow from, say, -10 C to +1 C as it does to heat liquid water from near-zero to boiling point. That is why I simply double the fuel amount. A crude rule of thumb, but effective.

As to pack volume: it is not that significant. 7 days x 30 g/day = 210 g of fuel – say one canister. Double for winter: two canisters. That extra canister is usually insignificant compared to the food volume.

Cheers

[Jeff McWilliams]

I took an Alpinism course with American Alpine Institute last year in late July and it was led by two young guys.  They were very knowledgeable in technical climbing knowledge and skill.  Other things?  Well…

We were talking about how much fuel to bring onto Mt Baker and water availability.  Someone asked, “What if there’s no liquid water readily available and we have to melt snow?”  Their answer was that, “It doesn’t take much more fuel to melt snow than it does to boil liquid water.”

Hmm, someone has never heard of “Heat of fusion”.  I didn’t know the numbers but I knew instinctively, and from college physics/chemistry a long time ago, that it takes significant amount of energy to change frozen water from a solid to a liquid.  Looking up the numbers:

1L of frozen water is 1kg.  It takes 334 kJ to change 1kg of frozen water into liquid water (at 0°C) (according to Google)

It takes 4,180 joules to raise 1kg of water by 1°C.  So to take water from 0° to boiling (100°), it would take… 418kJ

So:  liquid water at 0°C to boiling:  418kJ

Frozen snow to boiling:  752kJ

80% more energy,  i.e. 80% more fuel needed.

I’m going back this year because I got food poisoning on day 1 and had to bail.  (They’ve giving me a significant discount to retake).  Lousy luck of mine…

 

[Jon Fong / Flat Cat Gear]

Well, that is about double the fuel consumption to bring water to a boil.  And the same amount of fuel just to melt the snow as it is to boil.  Lets say that you normally you boil 1 liter a day and drink and wash with 2 liters per day.  That’s 4x the amount of fuel that you would normally take on a trip.  It all adds up.  My 2 cents.

[Jeff McWilliams]

Jon,

Absolutely!  It gives me new appreciation for when we’d use the MSR Whisperlite stoves and carry a big bottle of white gas.  Sometimes you really do need it if you’re melting a lot of snow.  It’s just too bad the stoves themselves are heavy.

[nunatak]

Jeff, we’ve been toying with hooking up a small isobutane burner head to a Whisperlite bottle and delivery tube/jet, using white gas. Not finished yet but it seems powerful, and def will be lighter when done.

View post on imgur.com

My impetus is that some pots I use are too small for the regular Whisperlite’s large burner circle.

[Jeff McWilliams]

Pretty interesting!

[Jon Fong / Flat Cat Gear]

What do you do to preheat the fuel?  Just curious.

[nunatak]

So far fuel pools inside the yellow aluminum block when one opens up the valve. The eventual base will have a cup or maybe just a fiberglass mat, as the stove is so small it preheats readily.

We also think that maybe it is rigid enough as shown and all we need, in addition to the primer mat, is a windscreen with spoke potholders, like this bigger Toaks and Firefly combo:

View post on imgur.com

View post on imgur.com

[Bill Budney]

Great idea to use a lighter-weight burner with white gas.

Dumb Question Department: What happens when you burn white gas in a spirit burner (alcohol stove)?

Do you get the synergy of energy-dense fuel with a simple and light stove, or do you get a big fireball that doesn’t last long enough to boil water?

Does it change if you add a mantle or wick? (Or does that just make it explode-y?)

(I could try it, but I figure someone already has. )

[Jon Fong / Flat Cat Gear]

Dumb Question Department: What happens when you burn white gas in a spirit burner (alcohol stove)?

You create very yellow, sooty flames.  You have to design a passive stove specifically to burn White Gas.  I made one before and it burned a blue flame.  That being said, while the energy density is high, the actual burn rate was low.  It took about 12 minutes to boil 2 cups.  At the end of the day, it did not seem like there was enough of an advanatge to develop it further.  My 2 cents.

[Bill Budney]

Oh, that sounds just tempting enough to make me want to try it! Perhaps a vortex-style burner, with a larger radius for more output? I’m sure you know more about it than I do, Jon. It’s my naïveté that makes the idea sound more tempting than it probably is in reality. I mean, if it really could work, then somebody would probably already be selling it.

I just like the idea of a lightweight stove burning energy-dense fuel (assuming that we can work out the details).

[Naomi B]

Altitude must be factored into equation. Oxygen for flames and stoves differs at sea level versus 3600 meters or about 12,000 feet.

[Jon Fong / Flat Cat Gear]

Altitude must be factored into equation.

Curious, why do you think that this is true?

 

[Bill Budney]

After further investigation, I see that white-gas-in-a-passive-stove has been discussed at length in the past:

Why Isn’t There an UL Alcohol Stove That Burns White Gas?

A simple alcohol stove more fuel effecient than the Jim Wood Super Cat?

Takeaways:

• It can be done fairly easily: Zelph demonstrates it, Dan Y states decent efficiency. (Newbie Question: Are they the same person?)
• Benefits over alcohol are… meh. Overall, alcohol is cleaner and nicer to work with.
• I now understand Jon’s bottom line better (above). The efficiency advantage of white gas is mitigated by an unpressurized stove.
• I also see why Nunatak is doing it the hard way: It may work better in the end.

 

[Jerry Adams]

alcohol has about half the energy density as white gas, butane, propane, and wax

you have to burn twice as much to generate the same heat

but since the stove weighs so little, the total weight is less

a white gas stove requires a pressurized container, pump, stove which weighs a lot

[Adrian Griffin]

Nunatuk, prime the stove with alcohol. When I cooked with an MSR X-GK II, I took a small dropper bottle of alcohol for priming.  No smoke or soot. Kept the jet clean.

I like your old-school aluminum Sigg fuel bottle. Just like my old one.

[Robert Pittman]

I let a little white gas bleed into the primer pan on the Whisperlite, shake it off at a safe distance,  and there is enough residue to light and warm up the start up, with out causing a BFE. (BIG flame event)

[David Thomas]

For reference (in furlongs per fortnight, ah, I mean BTU/pound):

Wood 8000-9700

Methanol 9,739

Ethanol: 12,754

Isopropyl Alcohol (the other IPA): 12,960

Carbon 14,104 (as charcoal, not diamonds)

Octane 20,582 (a component of and proxy for white gas)

Butane: 21,282

Propane 21,638

Methane 23,867 (a.k.a. natural gas) can be carried compactly as a liquid at -260°F)

While looking at those reference charts, acetone looked interesting at 13,248 BTU/pound because that’s better than methanol, ethanol or IPA and is available in the cosmetics aisle of any grocery store as fingernail polish remover.  Acetone has twice the vapor pressure of those alcohols, so maybe that’s helpful in some burner designs at lower temperatures?  Also, TSA allows it on planes – the first thing I’ve noticed with some real juice that they allow (alcoholic beverages over 80 proof and even firewood is prohibited).  Limited to under 3.4 oz / 100 ml in a carry-on and 2 kg total in checked bags with no one container over 500 ml / 17 fluid ounces.  Two liters of better-than-alcohol should be enough for any trip.  Experiment at your own risk (due to that higher vapor pressure).  From my Svea and Optimus use in the 1970s I can reassure you that your eyebrows will grow back.

6 fluid ounces of Equate brand “100% acetone” nail polish remover is $1.05 at Walmart!  Same price per ounce as 91% IPA and cheaper than red or even yellow HEET.  For an AT hiker who is at Walmart anyway to resupply, 6 ounces for your next leg would be just right.

[David Thomas]

For me, a deciding factor to essentially give up on white gas was the uncertainties in relighting it.  From cold, I’ve got my routine down and can avoid flareups.  When it’s warm or hot, I’m not so good at gauging the right amount of priming fuel and the priming fuel quickly goes to an explosive vapor on a hot stove, so in practice, I turn it down but not off and waste fuel in doing in letting it run.  Versus canister stoves that are so easy on-off that I do turn it off and use no fuel between dishes.  And when it is snow camping in a large group with snow-melting that would seem to suggest white gas, there are kids along, and I’d rather let them use the butane canister stoves without supervision than hover nervously over MSR white gas stoves.

And, a far number of such trips use a sled over a frozen lake (which is, invariably, remarkably flat).  So I just toss in some green “Coleman” 1-pound propane cylinders and don’t even need a Moulder Strip™.

[Bruce Tolley]

In reference to the comments above about whether one could build a passive burner white gas stove, the statement that a white gas stove requires a pressurized container and pump.

My recollection from reading about the Danish, Swedish and Norwegian polar expeditions at the turn of the century is that Nansen worked with the folks who founded Primus who designed a passive burner modeled on the marine alcohol stoves where the burner was on top of the fuel tank.  The Svea123 Safety stove with its cotton wick was a successor to this design.  I would estimate that the Swedish company Optimus and the US-based company MSR introduced stoves with remote pressurized tanks in the mid 1970s.

[Bruce Warren]

Very good article! One stove I would love to see you try is the PaintCan stove sold on Etsy and my website http://www.neotrekk.com. Tell me where to send one. It is an alcohol stove that uses absorbant stones that soak up the alcohol.  The PaintCan Stove comes with four hocky puck like Stones and if you light up all four under a pot it will do a great job of melting snow (I used ice cubes living near Houston). The flame size is optimal for transferring BTUs into the pot. And it works at any temperature or altitude. Adding more Stones under huge pots is easy. No stands needed. Four stacks of two stones under a 12″ diameter pot will melt a lot of snow.  -=Bruce Warren   [email protected]

[Jerry Adams]

the minimum is to use two stones, is that right?

and then you put them in the pill bottle, pour in alcohol and let the stones absorb for 8 minutes?

then put the two stones on the gold disk, and put your pot directly on the two stones?

the alcohol evaporates out the sides of the stones and then burns and flames go up the sides of the pot?

how much does two stones and the pill bottle weigh?  how much does it cost?

interesting innovative idea

so the bottom of the pot touching the stones won’t get hot, but the rest of the bottom and the sides get hot?

 

[Bruce Warren]

Hi Jerry,

Good questions…. I put answers inside your message below….

the minimum is to use two stones, is that right? >>>You can use any combination stacked or one high. You can simmer nicely with just one Stone. Our testing shows two stones stacked with an 18oz cup on top will heat up the water the fastest.

and then you put them in the pill bottle, pour in alcohol and let the stones absorb for 8 minutes? >>> it takes about 6 minutes for the 4 Stones to get saturated. Or you can keep the Stones in your bottle of alcohol. They burn for about 14 minutes and charge up in 6 minutes.

then put the two stones on the gold disk, and put your pot directly on the two stones? >>>Yes, the gold disc stops alcohol from seeping into the table or dirt. You can use a stove stand but having the top of the pot touch the Stone is important for max BTU transfer.

the alcohol evaporates out the sides of the stones and then burns and flames go up the sides of the pot? >>> Yes, that makes the optimum flame size for fastest cooking with the least fuel.

how much does two stones and the pill bottle weigh? how much does it cost?>>> see neotrekk.com for LOTS of details. Weighs 2.5oz and $39.95

interesting innovative idea

so the bottom of the pot touching the stones won’t get hot, but the rest of the bottom and the sides get hot? >>> yes, the pot is supported by the Stones an the flames come out the perimeter of the Stones. The big PaintCan Stove has Stones 3.5″ diameter which is great for big pots.

 

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