Have you ever come home from a trip and noticed that your digital clock was reset? This usually means there was a power outage, but you can’t know exactly when or how long the outage lasted, leaving you uncertain about whether your food is still safe to eat. Power outages can happen for various reasons—storms, maintenance, or issues with the grid—and if the outage was long enough, it could lead to thawing in your freezer, potentially spoiling your food. Thankfully, there’s a clever trick that can give you peace of mind when it comes to your freezer contents after a power outage.

This helpful tip, shared by Sheila Pulanco Russell on Facebook, can make all the difference in determining whether the food in your freezer is still edible after a power outage. Known as the “one cup trick,” it’s a simple yet effective way to check the condition of your frozen food without guesswork.

In her Facebook post, Sheila wrote, “I’ve come across a fantastic piece of advice for anyone leaving their home due to evacuations or those simply worried about keeping their food safe during a potential power outage. This trick is known as the ‘one cup tip.’” The idea is straightforward: you place a cup of water in your freezer, allow it to freeze completely, and then put a quarter on top of the frozen water. When placed back in the freezer, this setup acts as a low-maintenance, easy-to-check indicator of whether your food is safe to eat if you suspect a power outage might have occurred while you were away.

Here’s how it works: If you come back home after an absence and find the quarter is still sitting on top of the ice in the cup, that’s a good sign! It means that the ice didn’t melt at all, indicating your freezer maintained a consistent temperature. You can safely assume your food stayed frozen throughout, keeping it at safe temperatures and preventing spoilage.

However, if you open the freezer and find that the quarter has sunk to the bottom of the cup, it’s a red flag. This means the ice melted completely and refroze when the power was restored, which suggests that your freezer likely got warm enough for food to start thawing. In this case, it’s best to discard anything that may have spoiled. For safety, foods that thaw and refreeze are at a higher risk of bacterial growth and can lead to foodborne illnesses if consumed, especially items like meats, seafood, and dairy products.

If the quarter is somewhere in the middle of the cup, it’s a partial warning. While the freezer may not have warmed up enough for a total meltdown, it did get warm enough to partially melt the ice. In this scenario, consider assessing each food item individually. Softer items, such as ice cream, may have thawed and refrozen, resulting in a changed texture and possibly affecting safety. For other foods, use your judgment and consider how much they might have thawed.

Why does this trick work so well? Ice has an incredibly low melting point and takes a while to melt in an insulated environment like a freezer. If there was a power outage, any rise in temperature would cause the ice to start melting, causing the quarter to sink gradually as it melts. When power is restored, the freezer returns to freezing temperatures, but the quarter’s new position will tell you how much melting took place.

Sheila suggests keeping this cup and quarter setup in your freezer at all times for peace of mind, especially if you live in an area prone to outages or power issues. She advises, “Just keep the cup in there, and if at any point it makes you uneasy or if the quarter moves to a different position, just toss the food. Your peace of mind and health are worth it.” This trick can be especially useful for those living in regions where hurricanes or storms can cause prolonged power losses. Instead of worrying about the unknown, you have a visible sign to guide you in deciding what to keep or toss.

There’s another benefit to this technique. Beyond the simple check on food safety, the cup-and-quarter trick is useful even in short-term power interruptions, which can often go unnoticed if you aren’t home. A quick look at the quarter’s position tells you if the freezer experienced any temperature fluctuations that could compromise food safety.

If you find this trick valuable, consider sharing it with family, friends, and neighbors. Sheila’s advice has already reached thousands through social media, and it’s the kind of life hack that could make a big difference during an emergency or evacuation. Knowing that you can verify the safety of your food brings peace of mind and potentially saves you from foodborne illness.

With the simplicity of a cup, some water, and a quarter, this method provides reassurance and eliminates the guesswork of deciding what’s safe to eat after a power outage. Next time you prepare your home for a trip, remember to set up this quick and easy safeguard in your freezer. After all, it’s always better to be safe than sorry, especially when it comes to your health and safety.