Calculating camp fuel wrong, falling short on camp fuel, or unnecessarily carry extra fuel-all are annoying for campers and backpackers. When you learn to perfectly calculate the fuel requirement for the entire trip, these problems won’t arise. So, here we have come up with the easiest way to calculate fuel for you.
The equations are explained in the simplest way so that anyone can understand and make an estimation on their own. Other camp fuel relation questions are also answered at the later part of this write-up. All your confusion about using camp fuels will be vanished after reading this.
Basics of Fuel Calculation
To calculate your fuel requirements, first, you need to acknowledge ‘boil time’ and ‘burn time’. The rest of the calculation is easy when you understand these terms and the need for them.
Boil time is the time your fuel takes to boil 1 Liter of water. The time varies due to the user’s fuel efficiency, temperature, elevation, and so on. But at the optimum condition, it takes around 3 minutes and 30 seconds to boil 1 liter of freshwater.
The time your stove takes to burn out all the fuel from the canister is called burn time. This depends on the stove specification and the type of fuel used. Again, in the optimum situation, it only takes an hour (60 minutes) to burn out a 230 gm canister of cooking fuel.
Following are the three equations that you need to solve to determine the amount of fuel. If you already know the boil time and burn time for the stove, specific fuel, weather, and elevation, the rest of the calculation is actually easy.
The first step is to determine the amount of water you are going to need for cooking. Say, you will need half a liter of water for breakfast coffee and cereal-milk, another half-liter for lunch, another half for dinner, and half a liter for snacks, hot drink, or coffee in the evening. Then you will heat up around 2 liters of water for a day’s worth of food.
Now, the equation to measure the estimated time to boil 2 liters of water is:
Water Needed x Boil Time of the Stove per Liter of Water = Total Boil Time
As you are boiling 2 liters throughout the day, the total boil time is:
2 Liters x 3 min. 30 sec = 7 minutes.
So, you will be using the stove for 7 minutes throughout the day. Now, let’s figure out how much fuel is used in that 7 minutes. The equation to estimate that is:
Boil time for the Trip/Total Burn Time of the Stove = % of Fuel Used
Your boil time for a day is 7 minutes and the stove’s burn time for a 230 gm canister is 60 minutes. So, in 7 minutes, the fuel used is:
The percentage of fuel used is already a great way to figure out how many days a canister will last, right? But you can still do some more math's to convert the percentage to gm to get even more accurate results.
% of Fuel Used x Total Fuel in weight (gm) = Fuel Used in Weight (gm)
Here, 10% of 230 gm is 23 gm. So, you will use approximately 23 grams in a day.
The cooking time or fuel estimate you calculate at home can be different in practical life. The fuel used by the stove depends on many things. Some are environmental factors and some are personal choices. However, here are the factors you should take into account while actually planning for the trip and predict the fuel portions.
Amount of Meals
It takes less fuel to cook or boil larger portions of food and drinks. So, if you are traveling with a big group or cooking the entire meal for a day at once, then less fuel will be used.
People use fuel to warm up drinking water during cold days. Some even use this to melt snow. So, more fuel will be used in the winter season. Besides, soups and coffee take more in cold weather. On the other hand, in summer, if you are using a water filter for drinking water, then you can actually save on fuel a lot.
Type of Fuel
There are different types of fuel used in camping. Some are liquid form and most are gaseous. Liquid fuel can be used with a windscreen to minimize heat loss. So, those are effective compared to gas canisters.
On the other hand, gas canisters are safer, but can not be used with a screen. So, it is a matter of personal preference. But the efficiency of fuel varies, you should take it into considerations.
The air pressure is low at high altitudes so is the boiling time. So, in the mountains, your water will come to a boil quite soon, but the food will take more time to boil, simmer or cook. Using a pressure cooker or increasing pressure on the stove is a great trick to surviving those situations.
Again, when it is hot, the stove will take less time to heat up. It is on the contrary when the temperature is low. So, before packing, just like checking rain for preparations, this issue should be considered to pack the right amount of fuel.
During backpacking, most people rely on canned goods. Some even prefer cold meals to save fuel. But it is okay if you want to indulge in oatmeal or pasta for one meal or two. But those items take longer to cook. Please note that all the equations we have discussed above are based on boiling time. If you want to simmer your gravy or make mac and cheese on the stove, then carry some extra fuel. As those dishes take a lot of time to cook to perfection.
The way you plan ahead your meal and stick to it plays a great role in fuel efficiency. When camping with partners or family, it is quite impossible to strictly hold onto a meal plan. But the closer you can follow the plan, the better will be your fuel usage. Read more: 15 Ideal Food to Take Camping No Cooking
How to Calculate How much Fuel is Left?
There are two ways to calculate the amount of fuel left over in the canister. One method can be done in remote locations, but another one needs to be done at home.
Using Kitchen Scale
We all have a kitchen scale at home. After returning from camping or before going to one, measure the fuel left in your fuel canister. Simply measure the weight of the metal of an empty canister. Then measure the weight of the used canister. Then subtract from one another. Now you have the weight of the unused fuel of the canister.
Weight of the canister with fuel-weight of the metal of an empty canister = leftover fuel weight
You will get the weight of the fuel in grams. So, this method precisely tells the amount of fuel you have.
This method can be done without any kitchen scale. You don’t have a scale at home or you want to check how much fuel is left during the camping, then try this method.
First, put your full canister in a bowl of water. Find the floating edge and use a permanent marker to mark this line. You can also write (full) on that line for better understanding.
Now, after using this very canister for a day or two, when you want to feel like taking measurement again, just follow the former step again. Put this canister in a bowl of water. Now more portion of the canister floats as some of the fuel is used and makes it lighter than before. You can mark this floating like as (Day 1 or Day 2).
So, this is basically the way to assume the fuel you are using in the camping. If you have a spare canister in your reach, you can put that one in the bowl too. Now you will have a floating line for a totally empty canister as well. Mark this line as ‘Empty’. You should find this spot on the canister you are using on the campsite and mark that ‘empty’ line too. So that, you can tell how soon this one is going to empty.
How to Increase Fuel Efficiency?
There are many ways you can increase your efficiency of using less fuel. Most of those are habitual. Once you make these your habit, you will start using less fuel at home too.
- Use a lid while cooking or boiling on the stove. There will be less heat loss and the cooking process will be a lot faster.
- Avoid meals that need simmering for a long time.
- Try using a thermos to keep boiled water hot for long.
- Use a pressure cooker in mountain camping.
- Start the stove only when the food preparation is done.
- Cut food portions in small size so that it takes less time to cook.
- Plan ahead of your meal before camping. Try not to ruin the plan in the camping.
- Use specially made windscreen for gas canisters. It weighs a little but saves fuel.
Frequently Asked Questions
How to Dispose of Used Cans?
If you are sure that the can is entirely empty, then it is better to puncture it before throwing it out. Use a screwdriver to puncture the can. Now it is safe to dispose of it in a waste bin.
How Long Will 100g, 200g, and 450g Gas Canister Last?
A 100g canister lasts 1 hour, 220g canister lasts 2 hours and 450g canister lasts 3.5 hours. This is called ‘Burn Time’. The burn time for a specific gas canister depends on the weather and altitude. The time specified here is measured in an optimum situation.
How Long IsoPro fuel or MSR Last?
The burn time for all the cooking fuels is almost the same. An 8 oz. canister of IsoPro, MSR, butane, or propane will last for 2 hours in high flame or 4 hours in low flame. This amount of canister is enough for boiling water for 2 people up to 4 days during summer.
Can Butane Canisters Explode?
If a butane gas canister is used with an integrated butane gas stove, then there is a potential risk of explosion if not handled properly. If the canister overheats and the shut-off valve of the canister are not working, then the canister may explode, causing burning injuries.
Can Camp Fuel Go Bad?
Actually, it won’t go bad if you keep it intact and in its best condition. Unused gas canister is usable for up to 7 years. A used canister should be finished using within a year or a couple of years.
Which One is Better for Camping Butane or Propane?
Butane has a higher boiling time compared to propane. So, it is not the best choice to use during winter camping. During summer, both of those are just fine.
I know that camp fuel is a life-saving item and new campers can’t get confident about their fuel consumption efficiency. This is absolutely okay for anyone who is new to camping or backpacking. It takes several trips to get an idea of how fuel calculation works in real life and how to take control of it.
The fuel consumption varies from season to season and wind speed. So, don’t hesitate to pack some extra to stay ahead of time. Mastering the skills of hunting and cooking with forest wood will eventually minimize the dependency on cooking camp fuel.