Stoves for Cold Weather I

OK, so last month, we talked about gas stoves, and we pretty much concluded that if it gets below about 20F/-7C, then hey, you’d better stop using gas, right? Wrong. Well, not 100% wrong. Let’s just say that’s true for most gas stoves –- but not all.

Whoa, whoa, whoa, hold the phone here. How can some gas stoves work when others will not? Gas is gas, right?

Well, yes, but it matters how you use it. Last month, we talked about upright canister stoves where the burner mounts directly on top of the canister. This month, let’s talk about remote canister stoves. Like the upright canister stove, the remote canister stove runs on a canister of gas, but instead of mounting directly on the canister, the canister is off to the side and is connected to the burner by a fuel hose. Some remote canister stoves can easily operate in weather that’s twenty degrees or more colder than an upright canister stove.

An example of a remote canister stove is the MSR WindPro.
gas stove_1
Note how the burner is off to one side and the canister is off to the other, connected by a fuel line.

There are a couple of advantages to a remote canister stove. First, since the fuel is away from the burner, it doesn’t hurt to use a windscreen. Think about it. If you use a windscreen when the tank and the burner are together, that windscreen is going to trap the heat and that heat is going to go right into the canister. Heat + fuel = KABOOM! You wouldn’t want that; trust me. Separate the two, and a windscreen around the burner no longer traps heat near the fuel. In fact, quite the opposite, the windscreen now protects the fuel from the heat of the burner. Plus, a windscreen is a big help in the real world, particularly in cold weather, where a cold wind can prevent water on an upright canister stove from ever coming to a boil.

Uh, Jim, that’s really nice that it can handle wind better, but where’s the part about operating in weather twenty degrees or more colder than upright canister stoves?

Ah, yes, very good. Now, here’s the part we’ve been waiting for: cold weather operation. Take a look at the burner below. Do you see that loop sticking up through the slot in the burner cup? You can’t see it here, but that loop attaches to the fuel line that runs back to gas canister. This is a pre-heat loop which is also sometimes called a generator. Note that the pre-heat “loop” many not always be loop shaped. Just trace along the fuel line from the canister, and if a portion of it is exposed to direct flame, then your stove has a pre-heat loop. If your remote canister stove has a pre-heat loop, then it can run in much colder weather.
gas stove_2

Why? Well, think about it. What’s the problem with gas stoves? In cold weather, the gas won’t vaporize. If the gas won’t vaporize, your stove won’t go. That pre-heat loop runs through the flame. Flame = heat. Heat vaporizes fuel. Vaporized fuel means your stove goes. Using the heat from the flame means we can operate the stove even in temperatures where the gas wouldn’t normally vaporize.

So how do I in practice make this work? You turn the canister upside down. Now, instead of pulling vaporized gas off the top, you’re pushing liquefied gas out the bottom. The liquefied gas is pushed down the fuel line, heated in the pre-heat loop, vaporized, and combusted at the burner. Voila! You have a gas stove running in cold weather. Now before you try this, for safety’s sake, finish reading this article, particularly the “how to actually do it” section.

An MSR Rapidfire remote canister stove running with the canister inverted.
gas_stove_3

This kind of set up will allow you to operate a gas stove down to at least 0F/-18C, probably colder. If you keep the canister warm, you can go a lot colder. As with any new technique, test it out before you go deep in the backcountry and your life hangs in the balance. By the way, I’m assuming here that you’re using a winter grade gas canister that has fifteen to twenty percent propane content and the rest isobutane. Do not bring a canister with regular butane for winter use.

How to actually do it
OK, not to make a big deal out of it, but I’m a bug for safety, so I’m deliberately breaking this down into steps. So, follow the freakin’ directions, OK?
1. Verify that your remote canister stove has a pre-heat loop. If you’re not sure, take it to a local mountain shop or other store with knowledgeable personnel; they should be able to tell you if you have a pre-heat loop. If they’re not sure, seek additional help. Don’t proceed until you’re sure your stove has a pre-heat loop.
2. Hook up your canister in the normal way (right side up) and fire up the stove.
3. Once the stove is in operation, give it a minute or so to warm up, and then turn the stove down low.
4. With the stove on low, gently invert the canister. Make sure you have something heavy on the stove so the stove won’t flip or anything.

That’s it. Once the canister is inverted, adjust the flame and cook just as you normally would. Note: Some stoves will have a coupling that rotates reasonably well. The stove pictured above is an MSR Rapidfire; its coupling rotates fairly easily. Others will not. The stove pictured below is an MSR Windpro. Its coupling does not rotate easily, but it still can be inverted because it has a flexible fuel line. If your coupling doesn’t rotate or your fuel line isn’t flexible enough to invert your canister, I do not recommend that you loosen the coupling to try to get it to rotate. If you loosen the coupling, you could cause a gas leak which could have explosive results.
gas_stove_4

It’s a good idea to keep the fuel warm since you need to run the stove the normal way for a minute before you turn the canister upside down. See last month’s article on stoves for tips.

Now, MSR and some of the stove manufacturers don’t advertise this capability. If using an unofficial feature somehow bothers you, no worries. There are stoves that are purposefully marketed with this type of inverted canister set up, for example the JetBoil Helios or the Coleman Fyrestorm. Just be aware that the Helios and the Fyrestorm are a tad pricey. There are plenty of remote canister stoves with pre-heat loops out there that will work just as well for a whole lot less –- if you’re willing to look for them.

Now, that’s enough technical stuff for crying out loud. Get on out there and have some fun, would you?

HJ

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