View Full Version : How much fuel to heat 2 cups water??
What's your stove, fuel, pot , wind shield and amount fuel to boil 2 cups water.
Zelph Starlyte stove, Denatured alcohol, Evernew 1.3 ltr, Caldera Cone Sidewinder, 1/2 ounce of fuel, 2 cups (70* starting) to a rolling boil in about 5 minutes and it continues to boil for almost 3 more minutes. This time to get a boil is a tad quicker with the yellow HEET.
Old Hiker
12-11-2016, 10:45
Pocket rocket.
Iso-propane canister.
Pot depends. Have a 2 pot system that nests into a longish cylinder. Didn't get back to me in time in Hanover, so I had to get a GSI Minimalist: https://www.amazon.com/GSI-50139-Outdoors-Haluite-Minimalist/dp/B0037DD3RO/ref=sr_1_2?ie=UTF8&qid=1481467190&sr=8-2&keywords=gsi+minimalist
Dumped the spork, since I had a spoon already. I like it, esp. the silicon pot grabber.
Did not use a wind shield this time. Always found a place out of the wind this time. Have a piece of Al flashing that I used before.
Don't know amt of fuel - one 8 oz canister would last me at least 5-6 days, 2-3 burns per day. I'd always trade out the used one for a new one in towns, so I wouldn't run out and have to carry the empty canister to the next town.
Zelph Starlyte stove, Denatured alcohol, Evernew 1.3 ltr, Caldera Cone Sidewinder, 1/2 ounce of fuel, 2 cups (70* starting) to a rolling boil in about 5 minutes and it continues to boil for almost 3 more minutes. This time to get a boil is a tad quicker with the yellow HEET.
70° water is that a normal water temp ????
Puddlefish
12-11-2016, 11:37
Zelph fancee feast. About 3/4 of an ounce of Heet or denatured alcohol. Evernew .75 liter pasta pot. More or less fuel depending on the temp of the air and the water I guess. I just kind of wing it. I carry the fuel in an 8 oz soda bottle.
I timed it once and promptly forgot the result. Out on the trail, it's just boiled when it's boiled. I found the stackability, small space in my pack, the weight, and the high flame pattern that doesn't set a picnic table ablaze to outweigh any speed concerns.
I also cook in a bag. If I cooked more extensively, I'd use a different system.
ScareBear
12-11-2016, 11:43
Zelph Starlyte stove, Denatured alcohol, Evernew 1.3 ltr, Caldera Cone Sidewinder, 1/2 ounce of fuel, 2 cups (70* starting) to a rolling boil in about 5 minutes and it continues to boil for almost 3 more minutes. This time to get a boil is a tad quicker with the yellow HEET.
Excellent data! Thank you! .42 ounce of fuel by weight then?
I think somewhere along the way, I figured it was about 0.1 oz of pressurized (canister) fuel for every cup of water boiled. That's with a standard Pocket Rocket and properly-deployed windscreen. The small cans hold 3.5 oz. of fuel, that's 35 cups, call it nine days at four cups per day. (Eg. Liptons noodles plus two cups of tea.) Only problem is, the canister itself weighs 3.5 oz, empty.
Slo-go'en
12-11-2016, 12:35
There are a number of factors which affect boil time. How cold the water is to start with, how windy it is, what the air temp is, how big the flame is (mostly a factor with canister stoves which you can regulate).
70° water is that a normal water temp ????
It is a bit too warm IMO. I have done test with 50 deg ambient air, no wind, 50 deg water, with a Snow Peak Giga canister stove I can boil a liter (4 cups) of water using 10 grams of fuel.
It is a bit too warm IMO. I have done test with 50 deg ambient air, no wind, 50 deg water, with a Snow Peak Giga canister stove I can boil a liter (4 cups) of water using 10 grams of fuel.
Very close to my estimate. ;)
8-9 grams. White gas or various compressed gas canisters. 2 cups water + 2 ice cubes to simulate Colorado mountains while testing in east Texas summer. Aluminum 1 liter pot + lid and full wind screen.
Wayne
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70° water is that a normal water temp ????
It is coming out of my tap in the kitchen. :D
Excellent data! Thank you! .42 ounce of fuel by weight then?
That's correct.
Moosling
12-11-2016, 14:43
Supercat standard cat can holebpunch stove, DIY windscreen out of some aluminum flashing. Half ounce of fuel or a little more for 2 cups rolling boil. I use a bobby pin to close my windscreen around my 1 quart monovo Chinese made pot.
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There are a number of factors which affect boil time. How cold the water is to start with, how windy it is, what the air temp is, how big the flame is (mostly a factor with canister stoves which you can regulate).
I would would guess most would understand these factors.
Thom
8-9 grams. White gas or various compressed gas canisters. 2 cups water + 2 ice cubes to simulate Colorado mountains while testing in east Texas summer. Aluminum 1 liter pot + lid and full wind screen.
Wayne
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I am at 5280' so that seems to be comparable.
Odd Man Out
12-11-2016, 15:35
A bit less than 15 ml of alcohol to boil 2 cups of 70 deg water in a bit less that 4 min using a DIY eCHS stove on a Al flashing pot stand that doubles a a windscreen and an Olicamp XTS 1 liter pot.
nsherry61
12-11-2016, 16:06
70° water is that a normal water temp ????
Starting water temp is almost irrelevant because the difference in temperature between 50* and 70* is so small compared to the difference between either 50* or 70* and boiling.
So, if your system can heat 70* water to boiling with 14 g of fuel, it will heat the same volume of 50* water to boiling with 16 g of fuel. Not a big difference and completely irreverent if you know your starting temperature and can do some basic math to correct for the difference, if you care.
nsherry61
12-11-2016, 16:16
FWIW: The effect of wind and relative effectiveness of windscreens can vary so much with little changes in wind speed, wind direction and minor changes in stove set-up that comparing small differences in stove performance in a real-world environment is almost impossible.
It would be cool to try and standardize a set of wind conditions to use in comparing stove system performance, especially since wind protection and stove reaction to wind often play much bigger roles in stove system performance than the underlying stove heat production or burn efficiency.
Odd Man Out
12-11-2016, 16:48
FWIW: The effect of wind and relative effectiveness of windscreens can vary so much with little changes in wind speed, wind direction and minor changes in stove set-up that comparing small differences in stove performance in a real-world environment is almost impossible.
It would be cool to try and standardize a set of wind conditions to use in comparing stove system performance, especially since wind protection and stove reaction to wind often play much bigger roles in stove system performance than the underlying stove heat production or burn efficiency.
The Wright brothers invented the wind tunnel so they could invent the sirplane. You could do the same for stove testing.
MuddyWaters
12-11-2016, 19:01
FWIW: The effect of wind and relative effectiveness of windscreens can vary so much with little changes in wind speed, wind direction and minor changes in stove set-up that comparing small differences in stove performance in a real-world environment is almost impossible.
It would be cool to try and standardize a set of wind conditions to use in comparing stove system performance, especially since wind protection and stove reaction to wind often play much bigger roles in stove system performance than the underlying stove heat production or burn efficiency.
I have minimal problems with wind.
But Im smart enough to use the items at my disposal to block it,
water bottles, food bag, logs, rocks, sleeping pad, body, keep low to ground, etc
Most people dont attempt to block wind at all, and its a huge factor in fuel usage, even for cannister stoves., where 99% never even have rudimentary windscreen.
But it is not usually that hard to mitigate if you put your mind to using items around you.
The more resistant a design is used, the less effort people will put into other methods.
It is coming out of my tap in the kitchen. :D
Ice.
Wayne
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I am at 5280' so that seems to be comparable.
Thanks. I appreciate similar results feedback.
My results were essentially equal for 2 different stoves and different fuels: Coleman Peak 1, Coleman fuel and Primus Himalayan MFS, Coleman fuel and Coleman brand, French made compressed gas fuel.
On the subject of stove sound -
If I can hear my stoves I know that they have fuel, are working and I didn't forget to turn them off.
YMMV
Wayne
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Ice.
Wayne
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Not backpacking in Alaska...but I've done the test with colder water before, the difference wasn't that much.
1/2 ounce denatured alcohol using the one piece Fancee Feest stove. Using a windscreen is a must ;-)
https://www.youtube.com/watch?v=dKAFAsPfC4s
There are a number of factors which affect boil time. How cold the water is to start with, how windy it is, what the air temp is, how big the flame is (mostly a factor with canister stoves which you can regulate).
On a canister stove, keeping the flame at a lower level is best for fuel usage. There is a modest time to boil penalty, but I am not in a hurry any way.
Secondmouse
12-12-2016, 12:09
1/2 ounce denatured alcohol using the one piece Fancee Feest stove. Using a windscreen is a must ;-)
https://www.youtube.com/watch?v=dKAFAsPfC4s
Shug says he uses 1oz, not 1/2...
Finally Hosh stated one of the most known boiling water time factors - altitude. Makes a difference. Without noting what Slo-go en and Hosh stated these discussions lose meaning and context.
nsherry61
12-12-2016, 13:37
Finally Hosh stated one of the most known boiling water time factors - altitude. Makes a difference. . .
Yes, but very little. Almost irrelevant (like starting temperature) compared to wind or general stove system design.
Boiling temperature drops by about 1*F per 500 ft, so 10* per 5000 feet which only effects boil time by maybe 10% or so.
What altitude seems to make a big difference for is cooking time because that 10-20*F difference in boiling temperature can significantly increase cooking time, apparently by about 20% per 1000 feet or about a factor of 4X going from sea-level to 10,000 ft, depending somewhat, of course, on what you are actually cooking.
Shug says he uses 1oz, not 1/2...
He uses a large pot big enough to stick his fingers down into to clean it. Did you ever see the video how he washes out his pot? He's got everything down to a science ;-) 1/2 ounce will boil 2 cups under ideal conditions using a 2.5 cup capacity aluminum pot etc etc :-)
I find that a variety of alcohol stoves with a variety of pots will boil 2 cups of water with a variety of starting temps at a variety of altitudes with about a half-ounce of alcohol, assuming that wind protection and pot height above the burner are optimized.
colorado_rob
12-12-2016, 13:51
Starting water temp is almost irrelevant because the difference in temperature between 50* and 70* is so small compared to the difference between either 50* or 70* and boiling.
So, if your system can heat 70* water to boiling with 14 g of fuel, it will heat the same volume of 50* water to boiling with 16 g of fuel. Not a big difference and completely irreverent if you know your starting temperature and can do some basic math to correct for the difference, if you care.yep, starting temp doesn't make a huge difference, if talking 10-20 degree differences or so. Everything else being equal, higher altitudes help, of course, because water boils at lower temps, but at AT altitudes, small effect, even the majority of the time on western trails. IIRC, boiling temp is 196 at 11k feet, and 95% of the time you're well below that.
Of course, it's generally colder up higher, slowing canister output a bit, slowing boil times, but small effect on fuel use, probably cancels altitude boil temps.
I recently ran a few tests, my jetboil sol ti takes 5-6 grams (scale flips between 5 and 6) per 2 cups, and pocket rocket takes about 8 grams, all testing with 60 degree water at 5900 feet elevation, 55 deg air temp. The time was always just under 2 minutes with jetboil, longer with pocket rocket.
Btw, the jetboil is mostly unaffected by modest winds, because flame is surrounded by heat exchanger, and no flame leaks out the side, wasting heat. I also failed to see much difference with power levels in jetboil, in fact, hihgher power should help, not hurt, so long as flame stays contained.
nsherry61
12-12-2016, 13:59
I find that a variety of alcohol stoves with a variety of pots will boil 2 cups of water with a variety of starting temps at a variety of altitudes with about a half-ounce of alcohol, assuming that wind protection and pot height above the burner are optimized.
QiWiz, I think you have summed up the reality of this discussion with uncanny conciseness and perspicacity!
Salinity of water can affect water boiling times as well particularly in the south west, south central, and western U.S. Not everyone relates everything specifically to the AT as if it is the default setting where, how, or when water boils. Just saying a wider perspective can possibly be helpful to provide context. :)
Since the OP did not specify boiling times for the AT specifically altitude should be considered. Even so since the elevation of the AT varies quite significantly from just above 100 ft in Bear Mt SP to more than 6600 ft at Clingmans Dome with real potential to be boiling water near both these elevations those elevation differences certainly contribute to different boiling times given everything else the same.
Instead of seeing each of these boiling time factors as not being significant each in themselves perhaps it's better to recognize the cumulative significance?...which is already being done anyhow with all these posts:
"What's your stove, fuel, pot , wind shield and amount fuel to boil 2 cups water."
"Zelph Starlyte stove, Denatured alcohol, Evernew 1.3 ltr, Caldera Cone Sidewinder, 1/2 ounce of fuel, 2 cups (70* starting) to a rolling boil in about 5 minutes and it continues to boil for almost 3 more minutes. This time to get a boil is a tad quicker with the yellow HEET."
"I think somewhere along the way, I figured it was about 0.1 oz of pressurized (canister) fuel for every cup of water boiled. That's with a standard Pocket Rocket and properly-deployed windscreen. The small cans hold 3.5 oz. of fuel, that's 35 cups, call it nine days at four cups per day. (Eg. Liptons noodles plus two cups of tea.) Only problem is, the canister itself weighs 3.5 oz, empty."
So, if your system can heat 70* water to boiling with 14 g of fuel, it will heat the same volume of 50* water to boiling with 16 g of fuel. Not a big difference and completely irreverent if you know your starting temperature and can do some "basic math to correct for the difference, if you care."
"FWIW: The effect of wind and relative effectiveness of windscreens can vary so much with little changes in wind speed, wind direction and minor changes in stove set-up that comparing small differences in stove performance in a real-world environment is almost impossible.
It would be cool to try and standardize a set of wind conditions to use in comparing stove system performance, especially since wind protection and stove reaction to wind often play much bigger roles in stove system performance than the underlying stove heat production or burn efficiency."
All my rambling on might seem unnecessarily anal but isn't that exactly what y'all are doing? :):rolleyes:
Finally Hosh stated one of the most known boiling water time factors - altitude. Makes a difference. Without noting what Slo-go en and Hosh stated these discussions lose meaning and context.
I'm old. I'm slow. I've been knowing this since forever. I figured anyone who had a passing acquaintance with physics would also know. Do I have to teach Y'all everything I know?
[emoji1][emoji41][emoji106]
Wayne
Ps: The boiling water won't be as hot at 10,000' as it is at 5,000'. Everybody knows that, right?
The next time you're shopping for a CDT or CT hike look carefully at the instructions on the label of Backpacker's Pantry meals.
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rocketsocks
12-12-2016, 15:41
Maybe it's been mentioned but the type of material the pot is made of can effect the time to bring water to a boil, and thusly effect the amount of fuel used. I have an aluminum pot (for home use) that takes forever to boil water, while my steel pot does it much quicker. In a small backpacking pot it would be negligible, but measurable all the same.
colorado_rob
12-12-2016, 15:48
Ps: The boiling water won't be as hot at 10,000' as it is at 5,000'. Everybody knows that, right?
I would have thought so, but the context of a post or two on here sounds like some think it takes MORE fuel at altitude than sea level to boil 2 cups. It takes less, all else being equal.
At 6000 feet, water boils at 201F, 11 degrees less than sea level. Considering you're bringing water from say, 70 to 212 at sea level, that 142 degrees rise, vs a 131 degrees rise at 6000', that's a minor savings of fuel at 6000', about 8%. A 2nd order effect, much like the effect of your starting temperature (55 vs 70 degrees, or whatever).
So, if someone by chance is interested in my 5.5 grams of fuel to boil water at 5900 feet, they should add a tad for whatever lower altitude they will be cooking at. Most long trails spend a lot of time well above sea level, so my numbers at 5900 feet aren't too bad to use nearly everywhere.
One significant effect would be how long you let it boil. I like my water as hot as possible, but once boiling, it doesn't get any hotter, you're just using fuel to convert the 212 degree (or less, at altitude)water to steam, wasting fuel. I turn off right at the beginning of the roll action, sometimes a bit before.
I'm old. I'm slow. I've been knowing this since forever. I figured anyone who had a passing acquaintance with physics would also know. Do I have to teach Y'all everything I know?
[emoji1][emoji41][emoji106]
Wayne
Ps: The boiling water won't be as hot at 10,000' as it is at 5,000'. Everybody knows that, right?
The next time you're shopping for a CDT or CT hike look carefully at the instructions on the label of Backpacker's Pantry meals.
Sent from my iPhone using Tapatalk
Yeah everybody knows it so well as they ignore it. :rolleyes: What's obvious isn't acted on so obviously. :D
I would have thought so, but the context of a post or two on here sounds like some think it takes MORE fuel at altitude than sea level to boil 2 cups. It takes less, all else being equal.
At 6000 feet, water boils at 201F, 11 degrees less than sea level. Considering you're bringing water from say, 70 to 212 at sea level, that 142 degrees rise, vs a 131 degrees rise at 6000', that's a minor savings of fuel at 6000', about 8%. A 2nd order effect, much like the effect of your starting temperature (55 vs 70 degrees, or whatever).
So, if someone by chance is interested in my 5.5 grams of fuel to boil water at 5900 feet, they should add a tad for whatever lower altitude they will be cooking at. Most long trails spend a lot of time well above sea level, so my numbers at 5900 feet aren't too bad to use nearly everywhere.
One significant effect would be how long you let it boil. I like my water as hot as possible, but once boiling, it doesn't get any hotter, you're just using fuel to convert the 212 degree (or less, at altitude)water to steam, wasting fuel. I turn off right at the beginning of the roll action, sometimes a bit before.
See, CR is finally getting around to putting some real quantifying to boiling aspects instead of generalizations which in each factor aren't that much but now you add in wind, how long you boil for, to what temp you actually raise the water(some go past 212 F!), temp of starting water, the energy in various types of fuel, altitude, etc blah blah blah and the same stove, same pot, same 2 cps of water now take perhaps 15-20% longer to boil....if you care.
Water does boil at lower temperature at altitude, however the combustion efficiency of gas decreases greatly with increases in altitude. Not sure what the difference is for a backpacking stove, but a propane or natural gas appliances must be re-jetted for higher altitude homes.
Cars lose several percentage points of horsepower for every 1000' of elevation gain.
Try driving your Prius over Loveland Pass and watch the line form behind you.
...
Try driving your Prius over Loveland Pass and watch the line form behind you.
There was no line behind my turbo powered wagon over Cumbres, Wolf Creek or La Vita Passes. [emoji3]
Ok, if memory serves me correctly, Loveland Pass might be a bit higher than the 3 passes that I crossed, but the turbo effect is the same.
Wayne
Turbo works, twin screws work better especially the German variety.
Loveland is almost 12k and pretty snarky with lots of hairpins. For a long time, it was the only way over the continental divide until the Eisenhower Tunnel was finished.
Winter drives can be white out, white knuckled and hard on flat land relatives.
Try driving your Prius over Loveland Pass and watch the line form behind you.
Did that pass in a "skierized" rental car once, in a heavy snowstorm after skiing A-Basin. Got almost to the top before it simply could not get traction any more. Did a 15-point u-turn with a huge line of cars backed up behind me. So sorry, people but there's no guard rail and it's a long way down. Sweating bullets the whole time. Got back down somehow, took I-70 back to Denver, got over the mountain just before that pass was closed.
I've driven to the top of Mauna Kea in a rental car. Just below the top, the pedal was all the way to the floor and the poor thing was barely making headway. I was getting a bit worried. Going down was fun... from 13,000 feet to sea level in just a couple of hours.
First day ever in Colorado coming from Lafayette, LA. Drove to the top of Pikes Peak in a 1961 VW Beatle. A Prius coulda sucked the doors off of the Beetle.
But we digress.
Wayne
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Secondmouse
12-13-2016, 00:56
He uses a large pot big enough to stick his fingers down into to clean it. Did you ever see the video how he washes out his pot? He's got everything down to a science ;-) 1/2 ounce will boil 2 cups under ideal conditions using a 2.5 cup capacity aluminum pot etc etc :-)
I know. I use your Fancee Feast stove almost every day to heat water for coffee and soup for lunch in my office.
I just didn't want you to think that's what he says in his video cuz he doesn't. he makes a pretty big deal about his 1oz bottle that he refills from a larger bottle. Shug's weird...
:D
MuddyWaters
12-13-2016, 08:59
Shug's weird...
:D
Dudes a born entertainer.
One Half
12-17-2016, 23:37
I just started using this stove: https://www.amazon.com/gp/product/B01E9UF41Q/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
I use a homemade windscreen (husband made it) from a red bull can.
Using a 220gm snowpeak gigapower fuel canister. Ran it for 2.5hrs before I went out with the stove on my camping trip. Tried to figure out how much fuel I would use. It was 13oz when full, 9.2oz after the 2.5hr burn, and 6.3 oz after using it in about 45-50 degree weather, windy, for about 2 cups water for maybe 8 meals plus maybe another once or twice for additional hot drink. So just under 3 ounces for let's call it 9 x 2cups. That would be 1/3 oz per 2 cups hot water.
One Half
12-17-2016, 23:38
I use a snow peak Ti pot. I think it holds 28oz if filled to the rim.