Thread: All about gas stoves.

Part 2 - Upright canister stoves.

OK, Im going to start running through these stoves in order of worst in cold weather to best. I'm going to use MSR stoves as examples for no reason other than they have every type of stove I'm going to talk about. I am not infering they are better or worse than any other brand.

I should also add now before it's too late that I am not a chemical engineer, a mechanical engineer or a stove designer. I'm just a fella who's damn stoves wouldn't work properly when he was tahr hunting and wanted to find out why. All information I share is what I've interpreted information available on the internet to mean. If you feel anything I post is incorrect or doesn't make sense I'm OK with being wrong, we'll find the correct answer together and amend the posts.






These are both upright canister stoves. They're called that because the canister is used in an upright position only. The one with the hose we would call an upright remote canister stove.

Most of us have got or used one of these types of stoves I would say. Have you ever noticed on a cold morning your stove starts off OK but it slowly dies down and then goes out or only has a tiny flame? You shake the canister and it's got plenty of liquid sloshing around in there so what's going on?
When we use a canister in the upright position we are drawing off gas vapour from the top of the canister. As we draw that vapour off the liquid gas boils some off to replace it. That boiling or evaporating requires a heat source. Think of a pot of water on your cook top at home, it requires heat to change from a liquid to a vapour.
So where does this heat that vaporisation requires come from? The surroundings. It will actually take heat from the liquid itself. Your liquid gas is cooling down from within the longer you run the stove. We know when temperature of our gas drops our pressure drops also. That's why our stove dies off even if we have plenty of fuel. This is one of the limitations of these stoves. How do we get around that? Well you need an external source of heat for that gas. One way we all know is to start off with a warm canister. It'll still reduce in output the longer we leave the stove running but it'll probably get us a cup of coffee.
Another way if we're going to be using the stove for any greater length of time is to put a small amount of water in the pot initially and start the stove. As the stove starts to fade we turn it off, pour the warm ( not hot) water into a container and sit the canister in that. Restart the stove and now your canister has a good source of heat it'll burn much better. Always remember, it's the gas temperature relative to it's boiling point that matters. Liquid water at 5C is warm for a gas that has a boiling point of -22C. It doesn't have to feel warm to your skin necessarily (better if it does though).
The other issue with evaporation inside the canister is that the mix ratio of our gas is going to get worse towards the end of the canister. That 'enough for one night' canister you have may leave you going hungry if you take it out on a cold overnighter.

These stoves will either be using a needle type valve and a jet or a micro regulator to control the flow of gas. I'm going to come back to this after we've run through basics of each type first because it gets a bit complex and I haven't thought how to write that just yet.