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Canister Stove Fuel Consumption....

Posted: Thu Dec 18, 2014 3:33 pm
by Snowtrout
The thread about the MSR stove had me thinking about my stove and how efficient/not efficient it is. My stove is an older Primus Techno Trail (works great, simmers awesome, zero problems) and my pot is a 2qt MSR Alpine pot. My usual cooking methods for my wife and I:

Breakfast-usually boil water for oatmeal and coffee/hot chocolate and occasionally cook something for 5-10 min.
Lunch-very rarely use. Sometimes a few min for making a quesadilla or boiling water for soup.
Dinner-usually cook by boiling/simmering 5-10 min (pasta, rice, poached trout, etc) and/or sometimes boiling water (soup, dehydrated meals, hot chocolate/apple cider). Sometimes the stove will be used multiple times that night (soup, meal, drink).

I have found I get about 5-6 uses (2-3 days) out of a 4oz canister and 10-12 uses (5 days) out of a 8oz canister using it this way. As for the canisters themselves, I haven't really seen a difference between the MSR, Snow Peak, Primus, etc.

Is this seem about right? Would making a wind screen out of tin foil or something else dramatically extend my fuel usage? Just looking to see what others think.

Thanks in advance

Re: Canister Stove Fuel Consumption....

Posted: Thu Dec 18, 2014 9:40 pm
by Wandering Daisy
I added a home-made windscreen and it really helped. I am not sure it is all due to wind blocking, because the windscreen is sort of funnel shaped so it may be radiating heat to the pot that would have otherwise been lost sideways.

Another thing that has helped probably more than the windscreen is solar pre-heating cook water. The first thing I do when I get into camp is fill my 2L platypus and lay it on a black item (stuff sack or gaiter) and angle it towards the sun. It warms up incredibly in one hour. Every little bit helps. If I were not so paranoid about a leaky bottle, I would sleep with my breakfast cooking water. When I used to do winter backpacking we HAD to sleep with our water. It always made me nervous but I never had any leakage problems.

Third thing that has made a difference is using a pot cozy with top and bottom. I now bring the meal to a boil after I add the dry food, and simmer only a minutes, then turn the stove off and put it in a cozy and let it stand about 5 minutes. I cannot eat just boiled food anyway - burns my mouth. I guess this is what professional cooks call "resting".

I also do real cooking, similar to you. Breakfast and dinner are about the same, one hot drink and one real-cooked meal. If I see I am going to have enough fuel, I splurge with a second hot drink before bed. The small canister lasts 3-4 days. The medium 7-8 days. The large 11-12 days. That is solo. It is hard to compare when my husband comes with me - he does a lot of fishing and we fry a lot of fish. For a 10 day trip I take one large and one medium canister.

I camp at high altitudes most of the time, so night temperatures often get near freezing. That means morning water is pretty cold. I think it actually is better in those conditions to get water from the lake rather than use what is left in the platypus overnight. I would guess the deeper lake water is actually warmer.

Re: Canister Stove Fuel Consumption....

Posted: Thu Dec 18, 2014 10:53 pm
by paul
A windscreen will help for sure - whether you'll notice a dramatic change depends on how carefully you have been selecting your spots to keep the stove out of the wind. But a windscreen helps to keep the hot gases right up against the pot longer even if there is no wind, so it will save you fuel regardless. But you have to be careful in how you use a windscreen with an upright canister stove, as you don't want the canister to get hot. I use a foil windscreen to surround the stove less than completely - keep the downwind side open, so you can reach the valve and so you can check the canister. You should be able to touch the canister comfortably. if it's too hot to touch it's too hot period.

Re: Canister Stove Fuel Consumption....

Posted: Fri Dec 19, 2014 12:38 pm
by Snowtrout
Thank you for the replies. Pre-heating the water and getting water out of the lake (vs. water bottle) on chilly mornings are great ideas.

As for a windscreen, would it be better to make a thicker one out of a pie pan tin that could be used on multiple trips or use regular aluminum foil to make one for that trip?

Anyone have any pics of windscreens they have made for their canister stoves? So I can get an idea on what it should or could look like.

Re: Canister Stove Fuel Consumption....

Posted: Fri Dec 19, 2014 12:54 pm
by rlown
a pic of a windscreen in use at Puppet Lk. came with the stove, and obviously not a can stove. same principles apply.
Puppet Lk 2010 091.jpg
It's about 5" high by 24" long (aluminum.) it has 1/2" holes around the lower section to allow air into the stove.
As you can see in the pic, we were shielding the windward side only. When boiling water, I button up the shield tighter around the stove.

Another thing I didn't see mentioned yet. When you boil water, put a lid on it.

I think pie plate thickness is ok. If it's windy, your foil idea will blow away.

Re: Canister Stove Fuel Consumption....

Posted: Fri Dec 19, 2014 2:07 pm
by longri
A pot lid is important. Matching the flame size to the pot diameter also helps. If the flame is licking up the sides of the pot then turn the stove down.

I use a foil wind screen:
6111.jpg
It weighs just under 1 ounce. It's 4 sheets of foil which I find has sufficient stiffness to work, although I usually buttress it with my shoes or rocks or whatever. With 8 sheets that's not necessary. The nice thing about foil is that it's cheap, it folds up to fit into a pot, and when they wear out you can make a new one in about 5 minutes.

Canister stoves are very sensitive to the wind. Even with a wind screen they suffer when it's blowing. But a wind screen is still better than nothing. They also help to keep the canister warm when it's cold.

For some reason I brought a second one by accident on this trip:
5988.jpg

You would think that a wind screen would improve efficiency because it traps heat. Maybe it does in the cold but I can't say for sure. It seems like it should. I have tried to test this idea at home, indoors, and there was no fuel savings at all when using a wind screen in those benign conditions.

The pot cozy idea may save you fuel but not save you any weight. Running a canister stove on simmer burns fuel at a slow enough rate that your cozy might be heavier than the extra fuel. It kind of depends.

I like the idea of using warmer water even though I have never done this. To a first approximation the amount fuel you use is proportional to the temperature you raise the water. So if you use 70° water instead of 40° water and bring it to a boil at 195°, you'll save (70-40)/(195-40) = 19%. That's not bad.

A Jetboil will save you a measurable amount of fuel.


Food choices make the most difference when it comes to conserving fuel.

Re: Canister Stove Fuel Consumption....

Posted: Fri Dec 19, 2014 4:27 pm
by Wandering Daisy
I made my own pot cozy from the blue foam insulating pad. It weighs 1 oz. tops. On longer trips it does save fuel. If you count even 3 minutes per meal x 2 meals x 10 days, that is 60 minutes less cooking. I would take my pot cozy anyway, because I am a slow eater and like my dinner to stay hot to the last bite.

My home-made wind screen attaches above the fuel can. Snow Peak actually makes a similar wind screen but it is made of stainless steel so is heavier. A friend who collects scrap metal made me one from aluminum - we think it used to be a reflector for a candle. It is cone shaped and when the pot is put on the stove it nearly touches the windscreen. So there is no danger of overheating the gas canister.

Re: Canister Stove Fuel Consumption....

Posted: Fri Dec 19, 2014 5:12 pm
by longri
Wandering Daisy wrote:I made my own pot cozy from the blue foam insulating pad. It weighs 1 oz. tops. On longer trips it does save fuel. If you count even 3 minutes per meal x 2 meals x 10 days, that is 60 minutes less cooking.
I checked once with my stove and it used 0.4 g/min when simmering. So 60 minutes of simmering would use up less than an ounce of fuel. A cozy would also be one more thing to carry. Burned fuel weighs nothing.
I would take my pot cozy anyway, because I am a slow eater and like my dinner to stay hot to the last bite.
That's a good reason.

I like to eat fast. :-)

Re: Canister Stove Fuel Consumption....

Posted: Sat Dec 20, 2014 2:04 pm
by rlown
longri wrote: You would think that a wind screen would improve efficiency because it traps heat. Maybe it does in the cold but I can't say for sure. It seems like it should. I have tried to test this idea at home, indoors, and there was no fuel savings at all when using a wind screen in those benign conditions.
The most important part of a windscreen (when it is windy unlike inside hopefully) is to keep the flame on the bottom of the pot. If it's blowing sideways, you lose efficiency. You also have to pick an appropriate place to set the stove. Sometimes you can get increased wind effects when near your favorite blocking rock.

Re: Canister Stove Fuel Consumption....

Posted: Mon Dec 22, 2014 11:03 am
by hikin_jim
Snowtrout wrote:Breakfast-usually boil water for oatmeal and coffee/hot chocolate and occasionally cook something for 5-10 min.
Lunch-very rarely use. Sometimes a few min for making a quesadilla or boiling water for soup.
Dinner-usually cook by boiling/simmering 5-10 min (pasta, rice, poached trout, etc) and/or sometimes boiling water (soup, dehydrated meals, hot chocolate/apple cider). Sometimes the stove will be used multiple times that night (soup, meal, drink).

I have found I get about 5-6 uses (2-3 days) out of a 4oz canister and 10-12 uses (5 days) out of a 8oz canister using it this way.
That usage might be a little high, but then you're doing a little nicer and a little more frequent cooking than I do.

On a grams per day basis, you're doing a more than 35g/day in terms of fuel consumption.
Image
I usually figure for just basic cooking about 20g/day for two people. If you're getting by with less than 20g/day, you probably are using some tricks or an integrated canister stove.

The biggest fuel saving "trick" is to turn the stove down. Stove use is far more efficient at say 50% of full throttle vs. 100%. It extends cooking time a bit, but not horribly. Maybe not a good trick when melting snow, but for most cooking, turning the flame down will save a good deal of gas.
Snowtrout wrote:As for the canisters themselves, I haven't really seen a difference between the MSR, Snow Peak, Primus, etc.
In warm weather, probably not much difference. With fresh canisters, probably not much difference. In colder weather toward the end of the life of the canister is where you would see the most marked differences. In cold weather, I'd go with a brand this just contains isobutane and propane (no "regular" butane). See: What's the Best Brand of Gas for Cold Weather? if you're interested.
Snowtrout wrote:Is this seem about right? Would making a wind screen out of tin foil or something else dramatically extend my fuel usage?
It could, especially if you were cooking a lot in windy conditions. If you've been very careful to always shelter your stove well, then it may not make a dramatic difference although it won't hurt.

You want to be careful with windscreens though. Get things too hot underneath there, and you can melt plastic any parts or worse BOOM. :eek:

HJ