What type of gas canister do I need?

All our stoves use a threaded gas cylinder, although they can run with a camping-gaz cylinder with an adapter. There are more blends of camping gas than there are blended whiskeys, and in the case of gas, a single malt isn’t always better. Most gas is a mixture of propane, butane and isobutane, in varying quantities which generally you don’t need to pay much attention to.

AlpChemistry

In cold weather below 10C (so pretty relevant in the UK year round), the blend of gas can actually be quite important. First time for an AlpChemistry lesson from an old GCSE Revision book. The boiling points of the main components are as follows:

Propane -42C
Isobutane -12C
Butane 0.5C

These are the temperatures at which the gas will vapourise, the higher the ambient temperature is above these temperatures the more the pressurised gas wants to be free and so exerts a higher pressure on the cylinder. Hence for camping we don’t use pure propane despite its cold weather suitability; the cylinder would need to be super thick and weigh a tonne! On the other hand, butane at 5C is very close to its boiling point so isn’t so fussed about being contained in a canister. But, this means that the vapourisation rate isn’t enough to power your general stove. A combination of these properties is needed, so we combine the gases! We can also add some isobutane to the mix, it’s basically butane with a facelift, same number of carbons and hydrogens just rearranged more efficiently so the boiling point is lower (I didn’t pass A level chemistry so can’t say why).

In short, for regular use a blend of butane and propane will be absolutely fine, but when the going gets cold, get a isobutane/propane mix (generally advertised as a winter blend) you will notice the difference, especially with our Kraku, Landar and Brukits. The Kraku is a little different as it has a preheating tube which acts a turbocharger for stoves in cold weather. The cold gas from the cylinder is heated well above its boiling point before burning so it burns more efficiently. This doesn’t change the overall pressure in the canister so isobutane is still an advantage, but you can also invert the cylinder to help boost performance.

Gas at altitude

This shouldn’t make a difference for stove use, in fact, the higher you are the greater the pressure differential will be which makes the gas work better. However, it also tends to get colder the higher you climb (about 0.5C for every 300m gain) which makes the gas not work as effectively. Ultimately this means that the gains and losses balance out so that altitude makes little difference! Though for an isobutane mix you are still limited to around -7C.

Make your stove work better in the cold

No-one wants to have to wait longer for their pasta to cook after a long day winter climbing, let alone when you’re camping in a freezing Scottish layby. So here’s a few tips for getting your Alpkit stove working better in the cold:

Start with a warm canister - stuff it under your jacket, or keep it in your sleeping bag between uses.
Keep it warm by insulating the canister from the snowy ground - a simple wooden chopping board works well if you’re car camping, or a bit of foam mat.
Get a windshield - if it’s cold, it’s probably windy, a Concertina will keep the precious heated air close to your pan and keep the flame from blowing out.

Created: Dec 20, 2016

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