Are you planning on going on vacation and leaving food in the freezer? Then you don’t want to miss out on this essential trick that will help you determine if it’s safe to consume the food you left behind. Sometimes, when we’re away from home, the power goes off without us even knowing. This can cause food stored in the freezer to defrost and spoil.

Fortunately, there’s an ingenious trick that can save you from coming home to spoiled vegetables and fruits! Sheila Pulanco Russell has come up with a simple experiment that uses just a mug of water and a penny. With this experiment, you can easily check if your refrigerator is still in optimal working condition.

Sheila’s experiment involves filling a mug with tap water and placing it in the freezer. If the penny freezes, it’s a good sign that your fridge is able to keep your groceries well-chilled and frozen. But if the penny doesn’t freeze, it probably means you’ll need to buy a new refrigerator to prevent food spoilage. Give this experiment a try at home!

In a Facebook post that quickly gained hundreds of thousands of reactions and shares, Sheila explains the procedure:

“For those of you who are evacuating from the coast, I just heard a great tip. It’s called the one cup tip. You put a cup of water in your freezer. Freeze it solid and then put a quarter on top of it and leave it in your freezer. That way, when you come back after being evacuated, you can tell if your food completely defrosted and refroze or if it stayed frozen. If the quarter has fallen to the bottom of the cup, it means all the food defrosted and you should throw it out. But if the quarter is either on the top or in the middle of the cup, then your food may still be okay. It’s also a great idea to leave this in your freezer all the time, so if you lose power for any reason, you’ll have this tip to rely on. If you don’t feel good about your food, just throw it out. The main thing is for everyone to be safe. Please SHARE this on your page.”

Remember, if you’re unsure whether food is safe, it’s better to be cautious and throw it out. Your health should always be the top priority.