Alcohol Stove Fuel Quantity

James, first, make sure that your alcohol burner has the correct diameter of flame to properly heat the bottom diameter of your cook pot. Some burners produce a flame straight up, and some produce a flame that is rather broad. If you have the wrong width of flame, then most of your heat will be wasted, and you will have problems with fuel efficiency. By the same token, if you have the wrong cook pot height above the burner, it will be inefficient. Some people would need more than one pot of water to be sufficient for a big meal, so you have to experiment to see what your fuel needs will be.

If you leave the burner going, 100% of the alcohol will be consumed, or until you snuff it out, which might be difficult. Some burners make it easy to pour fuel back into the storage bottle. Some are difficult.

–B.G.–

I'm sure you're aware of this, but just a word of caution about reclaiming fuel….

Make sure the flame is ABSOLUTELY out before reclaiming any of it. Often the flame can be tiny and invisible, depending on conditions.

Most alcohol stoves boil 2 cups of water using 0.5 – 1.3 oz (my not fully researched estimate) of fuel, so your 3 oz/day estimate sounds right.

I like the original Penny stove. It can be tricky to make despite its apparent simplicity, or you can buy one.

Some stoves are just an open or partially enclosed fuel cup, and you can recover fuel from these easily. With the Penny stove, it basically needs to be all burned up.

Consider a wood stove. It can be as simple as a tin can with some ventilation holes, or a $100+ titanium can with fancy ventilation holes (Bushbuddy). The fuel, and possibly the stove, is free. Your firestarting skills have to be good if the wood is at all damp though. I made a Bushbuddy-like stove from tin cans.

I use a Caldera Cone. I routinely boil 2 cups of 50° water on 12 grams of 90% ethanol. Edit: Including priming, spillage, pitch removal, and first aid.

This is a 4 oz Nalgene bottle from REI with a PackaFeather top. It is 4" tall, 2" wide, plus whatever the fill-tube adds. It required an O-ring in the cap to assure a leak-proof seal, which I found at the local hardware store.

It allows me to easily fill a stove, and more importantly, aspirate out any remaining fuel when I'm done. No measuring. No loss. No waste.

After the water boils I drop a "snuffer cap" over the stove, wait for it to cool, and recover the remaining alcohol.

Edit: Error in amount corrected above from 20 grams to 12 grams for boiling 2 cups of water.

Add some for priming, more if cold. Add some for spilling your hot pot of water too.

Fuel recovery
It can be done with most if not all alcohol stoves.
All you need is a cup that fits somewhat loosely over your stove. Drop that on top of it , leave it there for a minute or so . In practice if the "snuffer" is made correctly it will snuff the flame instantly.
You then turn the two upside down , let the burner drip the remaining fuel into the snuffer and pour that back into your container.
( I am assuming here a minimum ammount of common sense, IE a burning stove is hot…)
A Wihte Box stove snuffer and one for the 10-20 (Caldera Cone) stove)

(my CC snuffer is just foil shaped over the burner)

Quantity
It depends on your stove/pot/windscreen/stand (correct distance) water temperature/volume of water and wind and type of fuel.
(the higher the percentage of Ethanol the hotter/faster it will burn)
So it can vary quite a lot.
1 oz for 500ml is a good average.
Franco
Franco

A Caldera 10-12 stove is pop can.

Cut the bottom 1/2"+/- off another pop can, cut 4 slits up the side at 12,3,6,&10 o'clock, put it on a Full pop can, burnish the top edge to make it "grow" just a little.

Presto – a perfectly fitting snuffer that fits cleanly on the stove for transport, that adds 5 grams and virtually no volume.

I have to second Travis' word of caution: that flame can look awfully 'done,' but then you pour it back in and *pooof*…and depending on the type of fuel (white gas is especially explosive) it can be dangerous.

I generally know, with practice, how much fuel it will take to boil a certain amount of water. I make sure my stove is big enough to safely handle that amount, and then when I set it on, I know that by the time the water boils, the fuel will be almost certainly spent. No reclaiming, like I did in the beginning…

I use a cat food can stove similar to the one on Skurka's site, and denatured alcohol, mixed 50/50 with this green gooey stuff I found near that old crashed saucer thing I found in the swamp a few months ago… ;)

Dug
http://thf2.wordpress.com

James,

For me I find I don't want to bother with recovery…so I have worked out how much fuel I need in most cases per boil and just let it go out on it's own.

Recently I have been using a Titan ketle as my pot and a cat can stove. For dinner I boil 700ml of water for the meal and a hot drink….I use 30ml of fuel for that. I only need to boil 300ml of water for breakfast and use 15ml of fuel. So I know exactly how much fuel I need depending on how many meals I need to plan for.

I find it works for me and keeps it simple when I am packing.

Spend sometime at the house boiling water and figuring out how much you need for your setup. Takes the thinking out of it once you have a good feel for water requirements and fuel consumption.

What is an ounce?

I think the word often gets used in an ambigous way.

An ounce is both a fluid measure (volume) and a measure of weight (dry ounce). For water it doesn't make a difference: an ounce by weight of water takes up about an ounce of fluid volume.

But alcohol is less dense than water so an ounce by volume weighs less than an ounce by weight.

More precisely: Methanol is 0.791 g/mL at 25 °C, Ethanol is 0.789 g/mL at 25 °C, and water is 0.9970 g/mL at 25°C. That is, alcohol is about 0.8 times as dense as water, so an ounce by fluid volume weighs about 4/5 of an ounce by weight.

An ounce (weight) is 28.35 grams, so a fluid ounce of alcohol weighs around 22.4 grams.

At home, while you are packing up, alcohol is easily measured by weight. However, when out on the trail, you don't typically have your scale along, so the only way to measure alcohol is by volume. Lots of hikers have their alcohol storage bottles marked with fluid ounce marks.

–B.G.–

I have changed my cooking/stove set up this year after morphing from traditional white gas, to cannister, to a gram weenie all in one season. I also went to a Heine keg cook pot.

All in all I'm stunned by the ease and simplicity of the overall set up. There is efficiency and ounces to be gained for sure!

I use basically 4 tsp, or about 3/4 oz per boil for two cups. If the water is really cold, it doesn't quite boil, but its darn close. Its not been an issue. I don't reclaim any fuel as it burns up and makes it easy.

The biggest experiment for me is finding the right hole pattern for my stove to match the burn "blossom" I'm needing for my pot. Once that gets dialed in, the scale of efficiency really works.

I use an REI bottle as well for fuel storage. Empty weighs less than an ounce, and will hold about 5oz total, so more than enough for multiple day trips.

Go make some stoves, you will be pleasantly surprised how well they work. I found great aluminum bottles at our local Dollar store, in the hair dept, basically an aluminum squirt bottle. Good luck!