Why People Put Coins in Freezers — And What It Really Does

Life can change suddenly, and everyday household routines may be interrupted without warning. Events like power outages, extreme weather, or overlooked maintenance can stop a freezer from working, allowing food to thaw partially or completely before freezing again. This situation is especially dangerous for meat, seafood, and dairy, since bacteria grow quickly at unsafe temperatures.

Refrozen food often appears normal, making it difficult to judge safety by sight alone. Because of this, a simple trick known as the coin-in-a-cup method can be very helpful. It allows you to detect whether food thawed while you were away from home.

Short power interruptions might pass unnoticed, but longer ones can melt frozen items and then refreeze them. The coin method provides an easy way to check if freezer contents remained solid during that time.

The idea, shared widely online by Sheila Pulanco Russell, requires only a cup, water, and a coin. First, freeze the water in the cup, then place the coin on top of the ice and return it to the freezer.

If the power fails long enough for melting to occur, the coin will sink into the softened ice before it refreezes. When you return, the coin’s position shows what happened inside the freezer.

A coin still on top suggests the food likely stayed frozen. If it sits lower or at the bottom, thawing probably occurred, and perishable items may no longer be safe to eat.

This simple method reduces uncertainty by giving a clear visual sign instead of relying on smell or texture. Although it cannot replace proper temperature monitoring and food safety habits, it serves as a useful backup during unexpected outages.