Everyday life doesn’t always go as planned, and household systems can fail without warning. Power interruptions, severe weather, or even an accidentally unplugged freezer can cause frozen foods to thaw and refreeze. That’s a concern for items like meat, seafood, and dairy, which can become unsafe if they warm up too much—even if they later look perfectly fine.
Because refrozen food often shows no obvious signs of trouble, relying on appearance or smell alone can be misleading. This is where a surprisingly simple method can help. The “coin in a cup” trick provides a visual clue about whether your freezer stayed cold the entire time you were away or experienced a temperature rise long enough for food to thaw.
Setting it up is easy and requires only basic items. Fill a small cup with water and freeze it until solid. Once frozen, place a coin on top of the ice and put the cup back in the freezer. If the freezer maintains a safe temperature, the coin will remain on the surface. If the ice melts during a power outage and then refreezes, the coin will sink—showing you that thawing occurred at some point.
This method helps remove uncertainty by giving you a clear indicator rather than forcing you to guess. While it doesn’t replace proper food storage guidelines or temperature monitoring, it works well as a backup check. Combined with regular freezer care and safe food-handling habits, this small step can offer extra peace of mind and help reduce the risk of keeping food that may no longer be safe to eat.