How to tell exactly how much cooking gas is left
By Babu Tendu, January 20, 2026Ever wondered why your neighbour always greets the gas vendor with a smile but barely talks to you? Well, your guess is as good as mine. It is fear. Like you, they have been in a position where they had to stop cooking halfway through because their gas suddenly ran out.
There is nothing quite as frustrating as being in the middle of preparing a meal, with the onions already sizzling in the pan, only for the flame to flicker and die.
This is where having a good relationship with the gas vendor comes in. Those who are familiar with street survival would agree that being friends with a gas vendor comes in handy at this point. In many Kenyan neighbourhoods, having that connection means you can get a refill delivered at odd hours or even on credit when the month is “long.”
Trust and social currency actually work when it comes to these gas vendors, as long as they believe they either know you or know exactly where to find you.
Unlike your neighbour, you probably might not have that privilege, and that is where this article comes in. It is essential to be prepared when the time to refill arrives, and here are some easy steps to stay informed.
Instead of shaking the cylinder and guessing by the sound, which is often misleading, you can use science to your advantage.
The hot water hack
The logic behind this is simple. Liquefied Petroleum Gas (LPG) is stored under pressure and is extremely cold. Basic science dictates that when you heat the metal cylinder, the part with gas will absorb the heat immediately in order to stay cool.
The empty part of the cylinder, on the other hand, will remain warm because there is no liquid inside to pull the heat away from the metal.
To prove this, you need:
- Around a litre of warm to hot tap water.
- Your gas cylinder (Connected or not).
How to know the exact level of gas left
- Slowly pour the warm water in a straight line down one side of the cylinder from the top to the bottom. Ensure the stream is steady so the metal has time to react.
- Wait about 5 to 10 seconds to allow the temperature difference to stabilise.
- Run your hand down the side of the cylinder where you poured the water.
You will discover that the top part of the cylinder feels warm, and as you slide your hand lower, you will suddenly get to a noticeably cold point.
The cold line is the level of your gas at that particular moment. If the cold starts near the top, you are safe; if it’s only cold at the very bottom, you are cooking on borrowed time.
Other methods to be sure
If you do not trust this way, there are two other methods you can use. One method is to manually check the indicated cylinder’s weight using a weighing scale.
That is: (Weight of cylinder with gas – Weight of empty cylinder = Weight of gas remaining).
Lastly, if you are cooking a heavy meal (like boiling githeri), look at the side of the cylinder. Sometimes, a sweat or frost line will naturally form on the outside due to the rapid condensation. That line is your current gas level.
If you find out you’re running low but can’t get a refill until tomorrow, use a lid. Cooking without a lid wastes up to 30% more gas because the heat escapes. Keep it covered to stretch those last few grams!