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MELTING SNOW: Fuel Efficiency and Boil Time Comparisons of Four Gas Backpacking Stoves in Winter Conditions
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Home › Forums › Gear Forums › Gear (General) › MELTING SNOW: Fuel Efficiency and Boil Time Comparisons of Four Gas Backpacking Stoves in Winter Conditions
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Nov 17, 2005 at 5:41 am #1345291
On the PCT through the Sierras there is a red fungus? that grows on the snow. I know PCT hikers have gotten sick from it and I saw it myself on my JMT hike this past summer. Anyone know what that is?
Nov 17, 2005 at 9:58 am #1345305>red fungus? that grows on the snow.
You can Google a lot of decent info on this topic. Here’s one quick reference: <http://www.straightdope.com/mailbag/mpinksnow.html>
Interesting that it’s UV resistant, so my Aquastar probably wouldn’t be the best solution for purifying watermelon-snow meltwater.
Nov 17, 2005 at 12:40 pm #1345311good info. many thanks. was thinking that it might have been an algae (snow/water + red color), but couldn’t imagine how it would get there and wasn’t at all sure enough to venture anything but a mental guess. go figure.
>>”Interesting that it’s UV resistant, so my Aquastar probably wouldn’t be the best solution for purifying watermelon-snow meltwater.”
perhaps more research needs to be done. remember the UV range of the EM spectrum is divided into 3 sub-ranges, viz. UV-A, UV-B, and UV-C. both Steripen and AquaStar produce UV-C light primarily at the 254nm wavelength. also, recall that the UV-C range is the most bio-active portion of the UV range(s).
i didn’t look at all of the links, but one of them speaks of UV resistance. however, the range of wavelengths cited are UV-A and UV-B. these have less of an effect than UV-C. i also don’t know the level/intensity of UV-C the algae is exposed to in the Artic and on Mtns, and how this level compares to SteriPen and AquaStar levels/intensity.
i’m not saying UV-C would work, just that it may work better than UV-A and UV-B. the link had no info on UV-C. so, we are left wondering.
BTW, the cells are large enough that even a so-called “cyst” filter will remove them.
so, now our mother’s should also tell us “Don’t eat the pink/red snow either”.
EDIT:
be sure to read Rick’s later post. in it he mentions a toxin, hence filtering or any method that doesn’t deal with chemicals is not a viable method. bottom line: stay away from colored snow.Nov 17, 2005 at 1:00 pm #1345313I typically see pink snow in summertime conditions when there’s usually plenty of water available directly and it can be entirely avoided. Not to say that the algae can’t appear in meltwater!
On the topic, I do know folks who’ve ingested some of the stuff and report it gives them the runs, but nothing more dramatic. I’ve never seen it described as an acute health hazard.
Donning my speculation hat, the algae likely manufactures a toxin–in the manner of the famous red tide algae but not nearly as toxic. Killing the algae is probably not the goal; rather, you’d want to neutralize or remove the toxin. Perhaps carbon adsorbtion?
Best to avoid in the first place!
p.s. UV will kill algae, I’ve got a UV system on my koi pond to do just that.
Nov 17, 2005 at 1:10 pm #1345316I belive the Steri Pen water purifier uses UV light to kill bacteria
Nov 17, 2005 at 1:20 pm #1345317Rick,
regarding your pond’s UV system, do you know the wavelength and intensity/power level of the light produced?
Nov 17, 2005 at 3:41 pm #1345334Hi Paul,
My pond system emitter is 25 watts and has an output range of 250-280nm. The maker doesn’t give an intensity spec, but does note it’s 40% efficient in generating UV (I suppose the rest goes into visible light and heat).
These units are available in many wattages and sizes to match pond size and conditions.
FWIW the UV AquaStar has a target output 254nm at 4 watts.
Nov 21, 2005 at 11:48 am #1345611The Coleman is great for ease of use, no priming, but at 19F below, the flame was so low it looked like a low fuel burn. The MSRs workred like blow tourches. Glad my companions had those.
Nov 21, 2005 at 12:54 pm #1345618Frank;
At -19F? Or below 19F?
Nov 23, 2005 at 1:04 am #1345766> that you can save fuel by running the stove at less than full-tilt-boogie. I realized that when its really blasting, a bazillion btu’s are floating up into the air…So am wondering, if you used the Xtreme at a moderate setting, not as much heat escaping arount the side of the pot, if maybe you’d end up with boil times and fuel economy more like the Jetboil?
Yep. Moderate power, windshield, lid: I quite literally halved my fuel consumption.
Nov 23, 2005 at 1:07 am #1345767> The Coleman is great for ease of use, no priming, but at 19F below, the flame was so low it looked like a low fuel burn. The MSRs workred like blow tourches. Glad my companions had those.
Well, -19 F is a shade cool…
But no problem: just move the Powermax cartridge around so it gets a bit of radiation from the stove to warm it up. And insulate it from the snow of course.
As long as you can touch the cartridge (pain thereshold about 40 C) it is NOT too warm.Nov 23, 2005 at 1:45 am #1345773Dr. Caffin,
good suggestion on the radiant heating of the insulated cartridge. also, “full-tilt-boogie” (good one!), now i know what the “f-t-b” indication on my stove dial means.
“pain threshold” at 40C? that’s only 104F, and the cartridge is dry, not wet. “40C”, a ‘typo’ right?
maybe the ans. is still pain threshold, but the 40C is a typo?
Nov 23, 2005 at 3:30 pm #1345827The CDC recommends one minute of boiling, not ten, so far as I can determine. I will use two minutes if I feel the source has a high likelihood of contaminants. However, I’m careful about where I gather snow, and generally only melt it.
On an ancillary point drawn from this thread, what modding for weight loss is possible for a Coleman Xtreme?
Ted Ripley-Duggan
Nov 23, 2005 at 4:10 pm #1345828Ted Asked:
“On an ancillary point drawn from this thread, what modding for weight loss is possible for a Coleman Xtreme?”Ted I don’t understand the word “modding”. Can you explain please.
Nov 29, 2005 at 5:07 pm #1346171Modding = Modifying
Nov 30, 2005 at 7:04 am #1346207Great information from all. I have tried most of the stoves mentioned and have decided the Coleman Xtreme is my stove of choice for winter hiking. This past weekend temp’s ranged down to 11F and had no problems at all with the stove. I have used it in below 0F as well with the same results. Aside from a somewhat tricky canister insertion into the stove, the problems are almost non-existent compared to my buddy’s white gas models mentioned here. He gave up on the Dragonfly and now uses his whisperlite/shaker jet model. Few problems for sure but not as easy to use as the Xtreme. – John
Dec 15, 2005 at 1:09 am #1346976OK, I find myself with a question. Canister stoves are notoriously flakey in the winter. At least they are for me even in temperatures above 0°F with moderate winds. I can recall trips where a canister stove just plain did not work and the conditions were reletively warm and winds nearly nil.
So, what is it about the Coleman Xtreme and/or MSR Wind Pro stoves both of which use fuel canisters that enables them to work (or so it seems to be claimed) reliably at temperatures aroun 0°F (and perhaps below)?
On a strictly stock wieght comparison why should I not obivously go with the Wind Pro overr the Coleman Xtreme every time (no, I’m not going to modify an Xtreme or Wind Pro; I doubt I have the mechanical knowhow, let alone tools, to do it)?
** Ken **
Dec 15, 2005 at 6:41 am #1346983In a word, liquid propane…
The Xtreme, by design, uses canisters that have a tube in them that draws up the liquid propane. Propane boils off well below 0F (-44F comes to mind???). This allows the stove to work at sub freezing temps.
The wind pro is “just as bad” as any other canister stove in the cold, **UNLESS** you flip the canister over which allows the liquid propane to leave the canister “first”. Thereby behaving, more or less, like the native functionality of the Xtreme.
Dec 15, 2005 at 6:52 am #1346984If the wind pro does work that way when the canister is upside down, aren’t you going to get less use of a windpro canister once the liquid propane is used up?
Dec 15, 2005 at 7:01 am #1346985Actually, it’s because these stoves are able to take up liquid butane, not propane. Butane has a boiling point of more or less 32°F. In normal canister stoves vaporisation takes place inside the canister and once temperatures drop beneath 32°F, the vaporisation of butane slows down very fast (vaporisation of propane continues as long as temperatures are above -40°F).
In the Xtreme and in the Windpro in upside down mode, vaporisation of the liquid fuel takes only place in the preheaeter tube running over the burner head.
Dec 15, 2005 at 9:53 am #1346999Hi Ken and John-
I’d like to add a little to Tony and Tom’s excellent replies:
A liquid feed canister system (home-brew upside-down, or Coleman Powermax) has two cold-weather advantages over regular canisters. But first, some background.
Current generation canisters contain a mix of Propane and Isobutane, (plus sometimes regular Butane.) The problem with regular butane is that it boils at -0.5 degrees C. So if the ambient temp is below freezing, your fuel would not vaporize. Isobutane is better in that it has a boiling point of -11.7 degrees C. (Propane boils at -42.1 degrees C.) So, why not just use Propane in the canisters?? Well, Propane has a higher vapor pressure, so requires a stronger (heavier!) can — like the giant cans used for car camping, or your backyard BBQ. So, in order to keep the small canisters light, yet still work at low temperatures, manufactures use the Propane/Iso blend.
This blend approach is not completely trouble free, though. The different gases in the canister boil off at different rates. So, as you run the stove, the Propane is used up first — leaving behind the (iso)butane. This explains why partially used canisters are particularly bad in cold weather — there is little propane left in them.
To make things worse, the fuel in a regular canister vaporizes inside the canister as the stove is run. This causes evaporative cooling of the fuel, lowering it’s temperature. So even if you start off with a warm canister, after running it for several minutes, it will cool and it’s output will drop off or stop. That’s why canisters are problematic for things like snow melting where 30-40 minute boils are needed.
Ok, so what about the liquid feed canisters:
1) Since the fuel evaporation occurs outside the canister in a preheat tube prior to cumbustion in the stove, canister cooling is minimized during prolonged usage. This allows them to provide consistant output over long burn times.
2) The liquid fuel bled from the canister always contains close to the original mix of propane/butane. Because the fuel does not evaporate in the canister, the propane doesn’t get used up first. This makes liquid feed canisters perform more consistantly over the life of the canister.
[If you just invert a regular canister to get liquid feed, the final 10g or so of fuel won’t come out in liquid form and operation reverts more or less to regular gas-feed operation for the last few minutes of fuel use.]
Cheers,
-Mike
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