Have you ever returned home from vacation and wondered whether your freezer lost power while you were away? A popular trick involves freezing a cup of water, placing a coin on top of the ice, and leaving it in the freezer. When you return, check the coin’s position: if it has sunk, the ice may have melted and refrozen, suggesting a possible power interruption.
However, this trick cannot reliably tell you how long the power was out or whether food is safe to eat. If you suspect your freezer lost power, food that remained at or below 40°F (4°C) may be safe, while perishable food that stayed above that temperature for more than two hours should generally be discarded. When in doubt, follow official food-safety guidance rather than relying on the coin trick…