When hosting an event on the deck or patio, it can be frustrating to run out of propane or not have enough in the tank for grilling food. Fortunately, there are four methods you can use to check the propane level beforehand and avoid this problem.
How to check the level of a propane tank
1. THE WARM WATER, COOL HAND METHOD
To determine the propane level in your tank, follow these easy steps: Pour warm water over the tank, then run your hand along the side of the tank.
When the propane level in your tank gets low, you can feel that the temperature of the tank is cooler near the top. This happens because the hot water outside the tank causes the propane inside to react and create a temperature difference. Although this method is not exact, it can help you estimate when you might need to exchange your tank.
2. USING A GAUGE
With this easy solution, users can quickly measure the level of propane in their portable gas tanks. The gauges on most portable LPG cylinders indicate the proportion of propane remaining, starting at 100% when the tank is filled with 20 pounds of propane and decreasing as it is used.
This type of gauge relies on the pressure inside the tank to determine how much fuel is left. It is commonly available in home repair and retail stores across the country, and is affordable, simple to install, and easy to read. After installing the gauge, you can easily remove it when the tank is empty and reuse it on your next tank.
3. FOR MORE PRECISION: TIPPING THE SCALE METHOD
Although this method provides a more accurate measurement, you will need to expend some effort to disconnect the propane tank from the grill. Additionally, you will require a household scale and the patience to perform a few straightforward calculations.
To determine how much propane is left in your tank, place it on a scale and subtract the empty weight, which is typically between 17 and 19 pounds. A full tank holds 20 pounds of propane.
Pounds of propane remaining = [tank weight in lbs] - [“tare” weight: 17-19 lbs]
To estimate the remaining cooking time in your tank, you can use the formula by converting the net weight to gallons. Divide the net weight by 4.2 to get the number of gallons.
Gallons of propane = tank weight in lbs. / 4.2
Your grill's BTU per hour rating can give you a rough estimate of how much cooking time you have left in your propane tank, as a gallon of propane contains approximately 92,000 BTUs.
4. THE MATHEMATICIAN METHOD: HOW MUCH COOKING TIME DO YOU HAVE LEFT
To estimate the amount of propane left in your tank accurately using a predictive approach as you use up the propane, follow multiple steps of mathematical formulas. You will need a calculator for this complex method.
To calculate the amount of propane you need for grilling, follow these steps: one full tank has 20 pounds of propane. Divide the weight of propane by 4.2 to convert to gallons. Each gallon of propane produces approximately 92,000 BTUs of energy. You also need to know the BTU per hour rating of your grill and the heat setting you plan to use while grilling.
To calculate the shortest period you can cook with a full tank, use this formula:
Cooking Time = _______________________
Max BTU per hour of grill
Based on the information provided, your propane tank contains 4.76 gallons of propane which can produce around 438,000 BTUs. If your grill has a high setting with a rating of 30,000 BTU per hour, you can anticipate 14 to 15 hours of cooking time on the highest setting.
How to adjust for different cooking temperatures
To adjust the cooking temperature, you need to use the "K" factor which assigns a numerical value. For example, if you are using 3 burners out of 4 on medium setting, it has a K factor of .56. Use this K factor in the formula to adjust the temperature.
Cooking Time = _______________________
(.56 x 30,000)
At lower usage levels, the cooking time you can expect is about 26 hours. Although slightly complex, this formula can be an enjoyable activity and, with some adjustments, can assist you in estimating not just your cooking time but also the amount of propane you have used during each trip.
How do you know if your propane tank is expired?
Portable propane tanks usually have a manufacture or test date and an inspector's mark stamped on them. Although this is important information to know, it's not typically a concern for most people. It's good to keep in mind that portable propane tanks have a lifespan of around 10-12 years.