Simple canister stoves in borderline temps

It sort'of depends If it is well below freezing, you have to:
1) keep the canister warm (as you know how to do)
2) Prevent heat from escaping
3) Add heat as you cook

Jerry and Roger use a small piece of electrical wire to warm the canister. It hangs into the flame and wraps around the rim of the canister. This adds heat after lighting so evaporative cooling does not rapidly cause loss of flame. You can use a tight fitting wind screen in these cold temps, too. This will supply some radiant heat to the canister as well as provide more efficient operation. Monitor the canister with a finger now and then. It *can* overheat. Also, a small piece of plywood or foam will help to insulate against heat losses if you are on snow. There was a thread about adding warmer water to the bottom and covering this with a plastic lid of the correct size. A pan of liquid water works as well, simply place the stove/canister in a bowel of water. Note that the canister can float, so don't be surprised by it. Basically, toppers start to fail at around 40F. They reduce in available pressure as the temp goes down. Often, it will light at 14F and after minutes it will die out to virtually nothing. Keeping it above 32F (liquid water) will insure that it will burn. More pressure is generated at higher temps so it will not burn at the same rate it would have if it was 50F. All thse things will let a topper continue to work. All add a bit of weight.

An external stove system is prefered for cold weather, one you can invert and use the liquid fuel. Some stoves can handle this, they all need some sort of preheater or loop into or near the flame that warmes the liquid to acceptable temps before burning.

I believe Roger Caffin makes some high tech stoves that weigh about what a topper does. It works well at -10C/14F.

-10C in Surrey???

First, choose your canister. You want one with the maximum % of propane and/or ISO-butane you can find. Plain butane is next-to-useless when it's cold. Jetboil canisters are the best you can get in the UK – they have no butane. Look for the 230g size.

2) You will not have any problems with cold when the canister is full. The problems will start when the canister is approx half empty, because the propane and/or ISO butane will be largely used up, leaving mainly butane.

At this point, you need to keep the canister warm. Sit it in a bowl of luke-warm water whilst you are cooking.

A few months ago I saw the mountaineering film "Cold" about the first winter ascent of Gasherbrum II, an 8,000 meter peak in Pakistan. They had temps of -50F and you can see see them using a Jetboil. Not sure how they did it, but they clearly did.
Ron

I used my canister stove this winter in negative F temps, I had rigged up a windscreen before the trip, mostly to prevent heat loss from the stove to the pot. Worked very well, had the fuel warmed slightly by having in down my pants briefly. :) Another trick is dip in hot water that you had heated already while the fuel was still above 32F.
Duane

I'd just as well assume they sleep w/ their canisters. I certainly do when it's ridiculously cold.

I'd be nice to devise a way to either create a hanging kit where the fuel could be hung (upside down) just far enough above the stove, or an insulative pot lid which could accommodate the canister attached above it.

That way it can stay warm from the residual heat from below.

of course one would be foolish to use it when it's NOT cold.

It seems that we have been over this time and time again.

As you go up to really high elevations, like 6000-7000-8000 meters, the atmospheric pressure is greatly reduced, so "the gas comes out of the can" easier. It will work to colder temperatures that what would work at sea level.

Also, another advantage to using a hanging stove is that the rookie in the tent gets to position his sleeping bag directly underneath the hanging stove and pot. That way, he gets to hold a lit candle underneath the gas canister when it needs some help. Also, anything that slops out of the pot will fall on his sleeping bag. Such is the life of a rookie.

–B.G.–

But Bob, ULers can't be bothered with the weight of a candle! Just breathe on the bottom, while in your sb. :) Kinda like warming ones hands with your breathe when they get cold. Keepa puffing.
Duane

Joel. Yes.

"Joel. Yes."

Thank you. :)

And for the other replies. :)

This is just a fallback thing, I'm wondering if I can get away with it if I ever have to.

I will now buy suitable gas when it's cold, since it will obviously make life easier, and make sure I have some way to improvise a bowl.

Perhaps there is life beyond Esbit…