This post is part of the Backpacking Gear for Beginners course.
Why do you need fuel?
Stoves need fuel to burn. What kind of fuel you need depends on your stove.
Canister stoves use iso-butane canisters. These are small pressurized canisters like a propane canister for your bbq. They can burn hot and fast when the canister is new but they slow down as the pressure inside gets less and less. They don’t work well in freezing temperatures. These canisters aren’t refillable. Just buy a new one when it’s empty. If you are traveling, you can’t fly with these.
Liquid fuel stoves use a fuel bottle with some sort of liquid fuel. Most stoves use white gas available from any camping or outdoors store. Some special kinds of stoves can use kerosene or diesel but most can’t. They are refillable so you can take as much fuel as you need. You can fly with empty fuel bottles but make sure you have some documentation with the bottle to explain what it is.
Fewer large canisters, or more small canisters
For gas and liquid fuel bottles you can bring 1 large or 2 smaller containers. It’s the same amount of fuel. I prefer 2 small ones since you can split them between people and are easier to fit in between other items in your pack.
How much do you need per day?
You’ll need to find out how much fuel to bring. We need to do a bit of math for this. We’ll multiply how much water you need by how long it takes for each boil then divide by the burn time of your stove.
(Total liters * Boil time per liter) / total burn time of the canister = % fuel used
Let’s unpack this a bit.
First, how many liters of water do you need to boil? Add up all the water you’ll need to boil between breakfast, lunch, dinner, coffee, and tea for each person for all the days. You might end up with 3 liters each for 2 people. So 6 liters total.
Second, multiply your total number of liters (6 liters) by how long it takes your stove to boil each liter. Stoves usually take around 3 minutes to boil a liter, say our stove takes 3.5 minutes to boil a liter.
(Total liters * 3.5 minutes/liter)
(6 * 3.5 minutes/liter) = 21 minutes (total burn time required to boil 6 liters)
Third, we need to see what the burn time on your stove is like. For the popular MSR Pocket Rocket 2 stove, they will burn for 60 minutes on a 230 gram (8 oz) fuel canister. Take your required burn time in the step above and divide it by the total burn time for a canister.
21 minutes / 60 minutes = 35%
So this percentage is how much of the canister you’ll need for your trip. Multiply this by the canister size to get the weight of the fuel used.
35% * 230 grams = 81 grams of fuel for this trip.
Add a buffer
There are a lot of factors that affect how much fuel you are going to use. It’s never going to be exactly the same. Air temperature, wind, and elevation all can increase the amount of fuel to boil a liter.
It’s always good to have a buffer of fuel. Conveniently, gas canisters can’t be refilled so I always make sure I have enough fuel in a new, full canister and then bring a small used canister to start with. This makes sure you have a buffer of extra fuel and uses up the remaining fuel in old canisters.
Test at home
Always test your stove at home. Ideally you can test an entire small canister and see how many liters of water it boils at home. Then you’ll have a good idea of how many liters it will boil for your next trip. You don’t want to find out on the trail that it doesn’t boil the same number as the manufacturer says.
