Practical Backpacking™ Forums

Welcome to Practical Backpacking™ Forums (PBF).

You are currently viewing PBF as a guest which has limited access. By becoming a PBF member, you will have full access to view and participate in tens of thousands of informative discussions, to view links and attachments (photos), and will gain access to other special features. Registration is fast, simple and absolutely free! Click to Become a PBF Member! Be sure to also explore the Practical Backpacking Podcast.


Go Back   Practical Backpacking™ Forums > Practical Backpacking™ Safety & Sustenance > Backcountry Kitchen
HOME FAQ PBF GUIDELINES BLOG PODCAST GALLERY STORE CALENDAR Mark Forums Read

Backcountry Kitchen The Backcountry Kitchen forum is for the discussion of food and cooking gear related topics for backpacking trips (e.g. menus, recipes, stoves, fuel...).


Reply
 
Thread Tools Display Modes
  #1  
Old 01-08-2008, 02:11 PM
© 2006-2016 Practical Backpacking™ / All Rights Reserved
Tagless Tagless is offline
Practical Backpacking™ Junior Member
 
Join Date: Nov 2006
Location: North Georgia
Posts: 63
Lightest Weight vs Burn Time Ratio - Isobutane Fuel or Alcohol?

I am curious whether anyone on this forum has any information about which might offer the longest burn time in proportation to weight - isobutane/propane fuel mix or alcohol. I realize there are varables that should be considered - stove efficiency for instance. Let's assume, for conversations sake, that stove weight and efficiency are the same. Is there a more desireable fuel source in consideration of saving weight - isobutane/propane fuel mix in a canister or alcohol?
Reply With Quote
Please Consider PBF Sponsors
  #2  
Old 01-13-2008, 09:54 PM
© 2006-2016 Practical Backpacking™ / All Rights Reserved
natchez natchez is offline
Practical Backpacking™ Junior Member
 
Join Date: May 2007
Posts: 21
I did five day hiking cooking 2-3 times a day I burned about 6-8 o of alcohol in my SGT Rock copy stove with wind screen
Reply With Quote
  #3  
Old 01-13-2008, 10:18 PM
© 2006-2016 Practical Backpacking™ / All Rights Reserved
Reality Reality is offline
PBF Administrator & PB Podcast Host
 
Join Date: Mar 2006
Location: Oregon
Posts: 4,954
To answer your question, isobutane/propane is lighter and can be more efficient than alcohol. The canister weight can come into play for shorter/section trips.

Reality
Reply With Quote
Please Consider PBF Sponsors
  #4  
Old 01-29-2008, 06:12 PM
© 2006-2016 Practical Backpacking™ / All Rights Reserved
lgiusto lgiusto is offline
Practical Backpacking™ Junior Member
Backpack: GoLite Jam2
Sleeping Gear: GoLite Ultra 20 with Exped Synmat 7
Shelter: Tarptent Contrail
 
Join Date: Mar 2007
Location: Just shy of Atlanta
Posts: 51
I usually use alcohol for overnights or shorter trips unless the temps are lower than freezing. My setup weighs less than a canister stove and the fuel is much more cost efficient. But if I plan on a longer trek (3 or more days) or deep winter camping, then nothing is greater than the efficiency of a canister stove. The boil times can't be beat as apposed to a 6-10 minute boil time on an alcohol stove (and that is usually in prime conditions). And in the Winter you don't want to wait!
Reply With Quote
  #5  
Old 12-05-2009, 05:51 AM
© 2006-2016 Practical Backpacking™ / All Rights Reserved
madizazzo madizazzo is offline
Practical Backpacking™ New Member
 
Join Date: Oct 2009
Posts: 8
BTU per oz. of common fuels

Fuel for thought:
Here are the common fuels used for backpacking stoves, and their BTU content per ounce of weight.

Ethyl (grain) alcohol has 609 BTU per oz.

White gas (Coleman fuel) has 1,150 BTU per oz.

Propane/Butane gas mixes* average 1,336 BTU per oz.

Note that all figures are per ounce of WEIGHT a.k.a. avoirdupois ounce, not in FLUID ounces.

* Propane has 1,347 BTU per oz. & Butane has 1,326 BTU per oz. Actual BTU of mixes will vary slightly depending on the blend.

I chose to show the relative BTU's by weight since that's where all the discussion revolves. The other significant point is that these fuels vary significantly in the weight of their storage containers, with gas blends having the heaviest per BTU of fuel.

All properly operating backpacking stoves have about the same efficency in converting the BTU's of their fuel source into heat. Their ability to convert the heat in the fuel into heated water depends more on the size of the flame vs size of the water container, efficiently channeling the heat and avoiding pans too far away from the flame.

Windscreens both avoid heat lost caused from heat being carried away on a breeze, heat loss from an inefficient, distorted flame and by channeling heat toward the cantainer being heated.
Reply With Quote
  #6  
Old 12-06-2009, 12:52 PM
© 2006-2016 Practical Backpacking™ / All Rights Reserved
captn captn is offline
Practical Backpacking™ Regular Member
 
Join Date: May 2006
Location: Houston, we have a problm
Posts: 116
And a BTU is the amount of energy needed to raise one lb. of water one degree F.

So ... if your one pound of water is 50 degrees and you want to raise it to 212 degrees, you'd need 162 BTU's if your stove system is 100% efficient, which no stove system is.

Here's where the difference in stove designs comes into play ... a Jetboil, for example, is MUCH more efficient than a standard pocket rocket. A Caldera Cone Alcohol system is much more efficient than just a soda can stove and a windscreen.

Some stoves and some fuel combinations have different efficiencies at different ambient temperatures, etc.

It can get complicated.

My observations with my equipment would suggest that a good alcohol setup is between 15 and 25% efficient, but your mileage WILL vary.

I saw a good write-up somewhere but I can't remember where at the moment, but it would suggest that a canister stove setup becomes lighter at about 4 to 5 days out for a solo hiker. For multiple people the canister is more weight efficient at day one. A Jetboil, given it's initial weight, is more weight efficient at about day 3 out for me with a group of three.

Of course, this assumes that your stove is your only cooking method. Some people use campfires for nighttime cooking and an alcohol stove for breakfast, some people use a cozy with their system, that changes the dynamics, some people carry only one hot meal a day to reduce fuel requirements, and the list goes on.

Myself, I have several different options in both Alcohol stoves, a Jetboil, and a Gigapower stove ... I'll carry what makes sense for the trip I'm going to take to minimize both weight and fiddle factor.
Reply With Quote
Please Consider PBF Sponsors
Aquaponics 4 You
  #7  
Old 12-06-2009, 02:34 PM
© 2006-2016 Practical Backpacking™ / All Rights Reserved
richwads richwads is offline
Practical Backpacking­™ Associate Member
Shelter: Tarp
 
Join Date: Jun 2009
Location: California
Posts: 483
Quote:
Originally Posted by Tagless
Let's assume, for conversations sake, that stove weight and efficiency are the same. Is there a more desireable fuel source in consideration of saving weight - isobutane/propane fuel mix in a canister or alcohol?

Given that iso fuel is more BTU efficient, it's obvious that it's also more weight effective. But other factors (some already mentioned) come into play that you didn't consider.

Canister weight for the MSR fuels is about 4.1 oz for the 4 oz fuel size and 4.6 oz for the 8 oz fuel size. Compare your alcohol fuel bottle's weight for those quantities of fuel to see if the combination of alcohol fuel and bottle is light enough to compensate for the lower alcohol BTU content.

A bigger variable might be the efficiency with which you use your stove. With my Esbit solid fuel stove, I blow it out when boil time is done, and tend to use campfire for cooking more due to the hassle of lighting the fuel tablet. However, with canister fuel, I fire it up whenever I want hot water or whatever, even if the campfire's going, cuz it's so easy. I use about twice as much canister fuel per day compared to solid fuel. When I did use an alcohol stove, I recall the same careful concern about wasting fuel, but it was harder to put it out, and I wasted fuel sometimes by just letting it burn out.

For solo trekking the esbit is way more efficient than canister, weight-wise, at least for me. But I take a canister stove when I bring company because it's easier for them to use it when they want, and I make them carry the fuel .

No easy answers .
Reply With Quote
  #8  
Old 12-10-2009, 06:25 PM
© 2006-2016 Practical Backpacking™ / All Rights Reserved
atraildreamer atraildreamer is offline
Practical Backpacking™ Regular Member
 
Join Date: Apr 2006
Location: Providence, RI
Posts: 159
Quote:
Originally Posted by captn

It can get complicated.

My observations with my equipment would suggest that a good alcohol setup is between 15 and 25% efficient, but your mileage WILL vary.

I did an article at another forum on determining stove efficiency and managed to get methanol burning alcohol stoves to a maximum efficiency of ~ 55%.
This is under ideal conditions, and even small changes in your stove system setup may cause drastic changes in efficiency. My conclusion...find out what works best for you and stick to it.
Reply With Quote
  #9  
Old 12-10-2009, 08:28 PM
© 2006-2016 Practical Backpacking™ / All Rights Reserved
niallgar niallgar is offline
Practical Backpacking™ Regular Member
 
Join Date: Jul 2008
Location: Ontario
Posts: 134
MSR Pocket Rocket using MSR fuel...

I have found that I consistently use 9 grams of fuel to heat up 2 cups of water and simmer it. This is how I cook most of my food - things like spaghetti and Lipton side dishes. Even less for oatmeal, soups, or mashed potatoes. (I usually budget 11 grams per meal)

I usually have the burner set fairly low because I believe that to be more effecient than blasting it at full throttle for 3 minutes. I bring the pot up to a boil then turn the burner off and let it sit for about 5 or 6 minutes than turn on the burner and bring it up to a simmer for the last 2 or 3 minutes of cooking. I also use a partial tin foil windscreen and try to find / set up a sheltered spot with little or no wind to do my cooking

Trangia Alcohol Stove...

Using my Trangia out on the back deck I find it takes about 1.5oz of alcohol to boil / simmer a Lipton side dish. (I usually budget 2oz alcohol per meal) I have other alcohol stoves which are lighter, but I like the Trangia and you can save fuel in the stove itself.


By the numbers...

Having a partial isobutane canister is also a consideration for short trips. So long as you can accuraltely calculate how much fuel is left in the tank.
My empty MSR Isobutane tank weighs 116grams empty (4oz). Add 44 grams of fuel for 4 burns = 160 grams (5.6oz)

My opinion...

I think like others have said it comes down to how long you are out there for. I put the over under at about 3 or 4 meals. That's just my gut feeling and not based on any real accurate math.

under 4 meals - use alcohol / 4+ meals - use isobutane

Caveat...

When I'm only out for two nights my pack is lighter so... I tend to carry more convenience and food, which means I usually bring the Pocket Rocket.
Reply With Quote
  #10  
Old 12-11-2009, 07:29 AM
© 2006-2016 Practical Backpacking™ / All Rights Reserved
Mountaineerbass Mountaineerbass is offline
Practical Backpacking­™ Associate Member
Backpack: Osprey Aether
Sleeping Gear: Big Agnes Lost Ranger
Shelter: REI Quarter Dome
 
Join Date: Jan 2009
Location: West Virginia
Posts: 250
I pretty much agree with Niallgar.

As stated YMMV, according to your preferences. When one person says "2-3 nights", this may mean boiling two cups of water 3 times. To another this may mean boiling two cups of water 9 times, so it's hard to tell, when someone gives a length of time. I find it is better to think about the number of 2 cup boils.

For me, I give up on alky stoves after 2 nights. I boil something for breakfast and have coffee in the morning, and then something for dinner, and tea in the evening. So I boil 2 cups four times in one day. Which is probably more than most, but less the some.

So I feel the lightest for me is (YMMV):

alky 1-2 nights. (I will sometimes go with my canister for the convenience)
Iso mix 2-6 nights.
White gas for a week or more.
Reply With Quote
Reply


Thread Tools
Display Modes

Forum Jump



All times are GMT -7. The time now is 10:48 PM.

Backpacking Forums


Powered by vBulletin Version 3.5.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © 2006-2017 Practical Backpacking™
Practical Backpacking is a trademark of Absolutely Prepared™
Practical Backpacker is a trademark of Absolutely Prepared™
Practical Backpacking Podcast is a trademark of Absolutely Prepared™
Practical Backpacking Magazine is a trademark of Absolutely Prepared™