Forum Index » Editor's Roundtable » Lightweight Stove Systems for Group Cooking Part 1: Basic Framework for Selecting A Cooking Pot and Predicting Fuel Needs


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James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
Re: Re: Re: Fuel Energy Density on 11/27/2013 06:32:16 MST Print View

Jeff, Yes. There is always saftey concerns with carrying any type of fuel canister.

Some things to consider:
Resistance to the materials being contained
Temperture(min & max)
Expansion and contraction of the fuel, air, water and container materials
more...

PET bottles (a standard clear plastic soda, or water bottle) covers all these things fine. However, the caps for soda bottles have a seal that breaks down over time. After two years of use, I needed to change the caps I use because of this. Some car gas, with the additives and any impurities in the refinement process' can also attack the cap seals rapidly, thou much slower on bottles. It is fine for a month though.

The actual fuel cans are usually plastic. No difference.

However, there IS a concern with mixing these bottles up with your drinking water. Or, having someone else with you that will grab the wrong bottle for cooking, etc. I used to make a fuel "bladder" by heating the pet bottles carefully over a flame while filling them about 1/10 full with some fizzy soda. This actually forces the dumples out and removes the "flat" bottom. Sort'of the reverse of the blow moulding to create the bottle. This shape is not one anyone is familiar with or would mistake in the dark. Still, a light sanding with 1000grig sandpaper and marking with a permanent marking pen "XXX FUEL" around the bottle makes these a bit safer. Solo? I never bother with this and just use a different bottle. A coke or pepsi bottle for fuel. Gatoraid for water.

I tried the very thin water water bottles. But after 3 trips, I had one develope a small leak on one of the small bottom dimples. I just carried the bottle upside down after noticing a smell. Might be a bad bottle, but they might be too thin. I never tried it again.

The weight of WG stoves is not a lot different from a lot of others. The Simmerlite (now opsolete, but some are still available) was about 9oz and makes an excelent winter stove. You cannot cook or simmer on it, though. My SVEA 123r weighs about 17oz for the stove and wind screen, but is too small for two in winter. The weight of my old XGK is about 17oz (plus the fuel bottle for pressurizing 2.5oz.) The Reactor weighs about 11-12oz. The Windpro weighs about 7oz. A few ounces, compared with 30 pounds of pack weight for Winter, doesn't make much difference. Gone are summer's SUL trips. Even UL and Winter in the same sentence is sort of joke. Winter shoes and socks weigh more than the stove. Hey, ha...unless you do like Roger C's avatar.

I have heard on this forum that it is possible to rig a pump on PET bottles, but, I never tried it. They do contain several bars of pressure, though. Probably enough to feed a Simmerlite or the like. Some sort of thread adapter was undobtedly used. Perhaps a Gatoraid bottle for the larger mouth? Anyway, getting way off topic. My apologies.

Gary Dunckel
(Zia-Grill-Guy) - MLife

Locale: Boulder
Patio stove tests on 12/05/2013 11:27:19 MST Print View

I've been waiting for a couple of months to do some patio tests of a canister cozy concept that I've come up with. So we finally are 'enjoying' our first sub-zero *F temperatures of the season here in Boulder. Time to do some testing. I'm posting about it in this thread, because it seems to be somewhat relevant to the theme.

But first, I'd like to report on something that I learned last week, before this cold wave hit. I am using a Snow Peak Giga stove with an integrated wind screen and reflector. A detailed description of this setup can be seen in this 2 year-old thread:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=45927

The aim of this test was to compare the boil times and fuel consumption of 2 cups of 50* tap water with different levels of flame intensity in high wind conditions. It was a very windy day (gusts of up to 45 mph), with ambient temperatures of 50* F. I did 2 tests at each level of flame intensity, and averaged the results, which were as follows:

Flame intensity, Boil time, Oz. of fuel consumed

Very low, 6:00 minutes, .25 ounce
Medium, 4:45, .25
Medium-high, 4:00, .20
High, 3:40, .20

What is curious to me is that this stove was actually a little bit more fuel-efficient when I opened the valve more fully, which goes against conventional wisdom. The bonus is that the water also boils faster.

OK, enough of this. Let's get to the cold weather tests. I came up with an idea that I thought might help when using a canister stove in very cold conditions. I made a canister cozy from Reflectix and duct tape. In the following photo you can see the components. I cut the compass off an REI zipper pull to give me a cheap thermometer, which I secured to the bottom of a fuel canister with duct tape. This is there to allow me to monitor the approximate temperature of the canister, to be sure that it doesn't overheat. There is also a 1/8" piece of Lawson's Evo pad, and a slightly larger diameter piece of titanium foil. These act as a stable non-conductive base for the canister. What is not included in the photo is a single chemical toe warmer, which is the key to this whole setup.

Cozy components

The next photo shows the canister inserted into the cozy, and sitting on the insulating base:

canister in cozy

This final photo shows the stove and windscreen attached to the canister, ready for testing.

assembled setup

Yesterday morning the air was +10* F, it was lightly snowing, and there was no wind at all. I had placed everything on the patio table the night before, to let things get as cold as possible. I took the cold pot inside and put 2 cups of 50* F tap water in it and stepped outside to see if I could fire up the stove. For this first test I did not use a toe warmer, so everything was +10* F. I was somewhat surprised that the stove actually lit, after holding a Bic to it for about 5 seconds. There must have still been a little propane in the mix (Snow Peak canister fuel = 15-20% propane, 80-85% isobutane?). I had to open the valve fully to maintain a flame. The boil took 7:30 minutes, and it consumed .20 oz. of fuel.

For the second test, I placed a toe warmer under the canister, and fairly well sealed the bottom of the cozy against the Evo pad underneath.I didn't want to completely seal it, as the toe warmer needs a bit of air to feed its chemical reaction. I let the warmer do its stuff for 15 minutes before I fired up the stove. Just before I lit the stove, the little thermometer showed 45* F--it warmed things up nicely. By this time the morning sun was shining on the black duct tape of the cozy, so that might have helped to warm things up. The air was still only +10* F though. This time the stove fired right up. I only had the valve open about half way, which is all I needed for a robust and steady flame. The water boiled in 5:00 minutes, and again, used just .20 oz. of fuel. After the boil, the canister thermometer read 35* F. I assume that the canister had cooled itself slightly. The cozy and toe warmer combination seemed to do what I'd hoped.

Alrighty then, now comes the Phase II trial. At 5:30 AM this morning, the ambient temperature on the patio table was a bracing -9* F! Not a hint of a breeze, not snowing, just friggin' cold. All the stuff was left out on the table overnight, as before. Now I could find out what the real deal was. I put on my WM Flight pants, my warmest parka, my beloved BR beanie, and the BR down mittens Doug sold me, grabbed a mug of joe, and went to it.

The stove wouldn't even give a hint of lighting without the toe warmer setup. So I placed one, and went back into the house for 15 minutes. The toe warmer raised the canister temperature to +10* F, and the stove did light after a few seconds with the Bic. I had to turn the valve completely open to keep things lit. The flame was pretty weak, but it kept burning, slowly. I finally got a boil at the 23:00 minute mark. The boil consumed .25 oz. of fuel.

I think I learned what I wanted to know. The toe warmer concept does does seem to sort of work, at least until the temperatures go really low (its performance decreases as the temperatures drop). My results with the toe warmer setup at +10* F were about the same as the windy 50* F day test I first reported on, but at -9* F it sucked. Maybe a hand warmer with its higher heat output would work better. But I'm thinking that only something like an inverted canister or a copper wire feedback thingy will achieve decent results at 0* F or below. White gas, anyone?

These results confirm for me Ryan's observation that one uses about the same amount of fuel for a boil at any temperature. I also feel certain that very cold conditions will sap heat from the system, prolonging the time to boil. I'd love to have one of you physics types to tell us about partial pressures and how fast each type of gas gets used up. Would a canister composed of 25% propane-75% butane (eg, Optimus brand) function well at zero degrees until the propane is depleted? Actually, I might have learned something about this. Read on, I haven't told you everything yet.

I also tested my new 1.0 liter Reactor under the same conditions (I first tested the Snow Peak/cozy, and while it was cooling down I did the Reactor). For the Reactor, I used a new Optimus 25%-75% canister, no cozy, no insulating base, and no toe warmer. The results:

On the +10* F morning, The reactor fire up right away, it took 5:30 minute to boil, and it consumed .25 oz. of fuel. A slowish boil, twice as long as usual, but still OK.

But this morning, at -9* F, it was a far different story. It took 20 seconds with the Bic, and then it barely heated up. Never a bright orange glow, but just a bluish dancing flame. I placed the pot to capture what heat I could, and then after 4 minutes the blue flame went out. The higher propane content didn't do much at all, so I'm thinking that the Optimus blend is a dud for cold conditions. Maybe next time I'll try the MSR blend--it's likely the best-of-breed.

Thanks for indulging me, folks. Now I'll read what I've posted and correct my spelling errors before BG whaps me.

Edited by Zia-Grill-Guy on 12/06/2013 13:56:14 MST.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Patio stove tests on 12/05/2013 13:14:48 MST Print View

No whapping, Gary.

I was just staring at the first two photos. I tried to figure out how you get that butane canister to work... the one marked Empty.

--B.G.--

Gary Dunckel
(Zia-Grill-Guy) - MLife

Locale: Boulder
Re: Patio stove tests on 12/05/2013 14:23:02 MST Print View

That's a diversionary tactic, Bob, so that the little kids next door don't burn my house down when I'm not looking (they can't read). Blank canisters are also good for attaching a stove when I want to stare at a stove setup from across the lving room, like when the ball game is getting stupid, or when the news anchor is reporting something that doesn't interest me.

Thanks for not whapping. I must have gotten my spelling corrected just before you checked out the thread post. Hey, you hiking this week? You are getting a weenie version of this storm front we are enjoying. Don't forget your toe warmers.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Patio stove tests on 12/05/2013 14:29:26 MST Print View

Good test Gary - thank goodness for winter so it gets cold enough to do tests : )

You did two tests of each and averaged. What was the range of these two and how does that compare to the difference between low and high (.25 and .2)? This would give an idea whether that difference was due to randomness or really due to flame level.

When I was testing, it seemed like low level uses maybe 5% less fuel than high level but it could have been due to random errors.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Patio stove tests on 12/05/2013 14:40:19 MST Print View

Hi Gary

> I'd love to have one of you physics types to tell us about partial pressures and how
> fast each type of gas gets used up.
Been there, done that, you must have missed that article. :-) Try
http://www.backpackinglight.com/cgi-bin/backpackinglight/effect_of_cold_on_gas_canisters.html
for all the info you need.

Cheers
PS: some of the graphs in that article seem to have gone viral around the web.

Stuart R
(Scunnered) - F

Locale: Scotland
Re: Patio stove tests on 12/05/2013 14:42:24 MST Print View

Gary, to learn about partial pressures, read the Cold Canisters article

In short, 25% propane is good to start with but performance quickly drops off.
For more consistent performance with an upright stove, look for a canister with a high % ISO-propane, like Jetboil or MSR Iso-pro.

But to be honest, any upright stove is going to struggle at sub-zero F, you need to look at an inverted canister stove at these temperatures.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Patio stove tests on 12/05/2013 14:46:38 MST Print View

"Hey, you hiking this week?"

I was hiking just yesterday. The temperature on my patio this morning was -1 C. I'll let you ponder that number in your heart. That was almost as cold as it ever gets around here.

--B.G.--

Gary Dunckel
(Zia-Grill-Guy) - MLife

Locale: Boulder
Re: Patio stove tests on 12/05/2013 16:25:00 MST Print View

Jerry, the fuel consumption of each test only varied by a single gram, so each boil was essentially the same. But this was for only 2 tests of each flame level--hardly scientific, but functional (in the interest of saving some fuel).

Roger and Stuart, thanks for that link. I somehow missed the article when it was published here. I'll read it now.

Tomorrow morning I'll try the higher temperature hand warmers (and I'll closely monitor the heat output, Roger, I assure you).

Edit--I guess that I did read that article before. I remember that I found it a bit hard to follow (physics wasn't my strong suit when I did my pre-med), and I got tired of converting temps from C to F while reading it. So I took the general concepts, and let it go. Definitely a good article though.

Edited by Zia-Grill-Guy on 12/05/2013 17:25:52 MST.

E J
(mountainwalker) - MLife

Locale: SF Bay Area & New England
MSR WindPro II, Kovea Spider and Caffin stove heat output and CO on 12/06/2013 13:42:37 MST Print View

How do these inverted remote stoves compare for heat output and CO?

SAM LAMBERT
(sammyl) - F - M
Alcohol stove boils water at 0 degrees Fahrenheit on 12/12/2013 16:37:22 MST Print View

I did my own patio test with a small alcohol stove (Trangia) one cold morning at zero F (32 degrees F below freezing or -18 Celsius). The cup of water, the alcohol fuel and stove had been kept indoors at about 65 degrees F before I lit the stove in the snow (they could have been kept inside the sleeping bag with me all night if I had been camping). No wind, no windscreen. I did not record the time it took to boil the water, but it did not take too long.

The point is alcohol is not completely useless in severe cold -- it heats a small amount of water OK for UL type cooking, perhaps as useful as it would be in warmer weather. I did not try melting snow.

I would try some more thorough testing and careful recording of results if I still lived in a cold winter climate. Maybe someone else who does live there could do it.

Bob Moulder
(bobmny10562) - F - M

Locale: Westchester County
Winter fuel guideline for XGK, Whisperlite on 12/12/2013 21:39:57 MST Print View

Hi, folks!

I am new to the forum and this is my first post. However, for about the past 25 years I have participated in and led quite a few multi-day winter trips in the Adirondacks, Whites, Catskills and Katahdin in temperatures of -10 to -33degF. Our rule of thumb that worked uncannily well all the time with XGKs and Whisperlites was 1 pint of fuel (Naphtha... Coleman 'white gas') per person per day. This sufficed for cooking and snow melting, and if running water could be located we would sometimes end up with a little fuel surplus.

Bob Moulder

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Winter fuel guideline for XGK, Whisperlite on 12/13/2013 16:21:33 MST Print View

> 1 pint of fuel (Naphtha... Coleman 'white gas') per person per day.
Ahhh ... let's see.
1 pint is approximately 0.5 L. White gas density is ~0.78 g/cc.
So that's roughly 390 g per person per day.
Oh My God!

Typically I would budget ~60 g of canister fuel per day for the TWO of us, and typically I would double that for kero or white gas, to 120 g/day for TWO. That's 60 g per person per day for white gas. If I could find running water a lot of that came home. (Summer use was about half of the above.)

Welcome to BPL. I hope we can get your pack weight down a few kilos!

Cheers

Jeff McWilliams
(jjmcwill) - M
Re: Re: Winter fuel guideline for XGK, Whisperlite on 12/22/2013 08:53:16 MST Print View

I recently read over the ADK Winter Mountaineering School student handbook and noted this same fuel recommendation that Charles mentions. I assume, Charles. that some of the trips you led are WMS trips?

I was mountaineering with a group on Mt Olympus and Mt Rainier two years ago. The group leader insisted on an inefficient group cooking system, and making group meals that required simmering for 5-8 minutes. Dinner meal ingredients included stuff like cheese tortellini. Picture a huge aluminum pot containing food for 10 people. Three MSR Dragonfly stoves were running simultaneously under the pot, and they all had to be tended in case one ran low on fuel or air pressure.

Breakfasts were instant oatmeal type stuff. Lunches were usually no-cook foods that were easily consumed while walking or during short breaks.

We still didn't consume 0.5L per person / per day, and we were also melting glacier snow for water. For four days on Rainier, that would have been 20 liters of fuel!

The WMS handbook specifies freezer-bag-cooking type meals only, so I can't fathom why so much fuel is being used per day.

Does the ADK/AMC WMS use heat exchanger pots?

Both the AMC Mountain Leadership School and ADK/AMC Winter Mountaineering School appear to be very traditional, heavy pack type classes.

Edited by jjmcwill on 12/22/2013 08:55:35 MST.

Gary Dunckel
(Zia-Grill-Guy) - MLife

Locale: Boulder
JetBoil canister fuel composition on 12/27/2013 09:54:36 MST Print View

I'm not sure if this is the right place to post this, but I suppose it will do. I contacted JetBoil CS to ask about the exact proportions of the gasses in their fuel canisters, and this was her reply:

24.87% Propane
71.97% Iso-butane
3.16% Butane

Wow--this is some serious canister fuel for winter usage! I couldn't find this information anywhere on the web, so it was great of JetBoil's CS to provide it to me.

The drawback to JB fuel is that their small canisters contain just 100 gm. of fuel, as opposed to the 110 gm. that most other brands do. But the gross weight of a full canister is lower, around 6.85 oz.

Does anyone have an empty JB 100 gm. canister that he/she could weigh (include the protective cap, please). I'm curious as to whether the JB canister has been beefed up like the MSR and Optimus ones. I have assumed that it is necessary due to the increased internal pressure from having a greater % of propane inside. But maybe this isn't true, and that MSR and Optimus are over-engineering their canisters (thereby adding unnecessary weight).

Kevin Buggie
(kbuggie) - M

Locale: NW New Mexico
Re: Re: Re: Winter fuel guideline for XGK, Whisperlite on 12/28/2013 02:41:36 MST Print View

Page 26 of the ADK WMS handbook states to bring 10 oz. fuel per day if water from streams is available, and to consult trip leader on additional fuel required for melting snow.

Like Roger said, YIKES!

My Optimus Vega canister stove, inverted, might weigh twice the Caffin Evolution stove but is still a BPL dream snow-melter compared to white-gas stoves of my past.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: JetBoil canister fuel composition on 12/28/2013 18:08:33 MST Print View

> I contacted JetBoil CS to ask about the exact proportions of the gasses in their fuel
> canisters, and this was her reply:
> 24.87% Propane
> 71.97% Iso-butane
> 3.16% Butane

What she did not tell you about was the 5% dirt.

To explain: I have seen and tested these generic canisters. They come from China and have been branded in several ways. Yes, they cost less than the 'western' ones - even if the retail price is no different. The contents is unfiltered raw gas: dust and all. The dust blocks up a winter stove very smartly. Been there, suffered that.

Reality check: do you REALLY believe the Chinese control the propane content of the gas to that accuracy???? Two decimal places???? I will stick my neck out and say they could not even manage 1%. I doubt they even KNOW what the composition is today. Most Western companies will quote something like 70%, and hope to be within 5%.

In the case of the Chinese canisters, I suspect that they did ONE lab measurement at ONE time and got those figures by calculation, with absolutely NO regard for the accuracy of their measurements, and have blithely been quoting them ever since. Very clearly they have absolutely NO idea of measurement accuracy - or scientific integrity. Very Chinese.

If Jetboil are now buying cheap gas canisters from China and happily claiming those specs, then very clearly Jetboil has gone down the tube (technically speaking) and has NO idea of what they are talking about. Should you buy canisters from them under those conditions? I leave deciding that question to you. Just do not (ever) invert the canister!

Cheers

Gary Dunckel
(Zia-Grill-Guy) - MLife

Locale: Boulder
Re: JetBoil canister fuel composition on 12/28/2013 19:28:46 MST Print View

Roger, I'm so glad that you responded to my comment. I'm trying to figure out the best performing canister mixture that works for various ambient temperatures. For temps at/above, say +32*F (0*C), at 8000-10,000' evevation, do you think that a pure iso-butane content would be optimal? I mean, why bother with either propane or the lowly butane in those conditions? If so, why hasn't anyone marketed one?

And finally,

What brand of canister fuel do you respect the most, considering most mild conditions and moderate altitude?

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: JetBoil canister fuel composition on 12/29/2013 00:25:23 MST Print View

Hi Gary

Well, I returned the two Chinese 'Primus' canisters I had bought and got a full refund. I don't remember what I said in the shop (no, I did not shout), but they seemed happy to refund me and get me out of the shop!

My favourite canister for summer use - not fussed as long as it works. I use Kovea canisters a lot, and they (so far) seem honest. The MSR iso-butane ones should be pretty good too, ditto the Coleman ones if you can get the 30% propane version. Don't buy any 100% butane canisters unless you are desert walking in the summer.

For winter use I love the Powermax ones. Seriously. The French Campingaz ones also seem very reliable, along with the ones mentioned above if used inverted. But I have gone off the Primus brand after that incident, and I would not touch the Jetboil ones now either.

How to judge? If the gas composition is something like 30% propane / 70% butane, fine. If the canister quotes the gas composition to one or two decimal places it is likely Chinese, and forget it!

My 2c.
Cheers

Kevin Buggie
(kbuggie) - M

Locale: NW New Mexico
Chinese jetboil canisters? on 12/29/2013 07:12:03 MST Print View

@roger. Do you know by fact that Jet boil is using unfiltered gas? Or are you kinda ranting and conflating brands (Chinese primus)?

If the former, that would be significant for many users with the big JB designed for remote inverted use. Doesn't seem plausible. My JB canisters purchased in north America are labeled ' made in Korea', and never clogged my Vega, though I've only burned 5 canisters (inverted) worth of fuel in it this season.

Is there a different production model of JB canister you're referring too? Or only relevant to eastern hemisphere purchases?

Please clarify