Here’s where the trick comes in. Before leaving, take a small plastic bowl or cup and fill it with water. Place it in your freezer and let it freeze completely. Once the water is fully frozen, put a coin on top of the ice—and leave it there. That’s it. Now, when you return from your trip, check the coin. If it’s still sitting on top of the ice, nothing changed. Your freezer stayed cold the entire time.
But if the coin has sunk into the ice—or is frozen somewhere lower down—it means the ice melted at some point while you were away. And that only happens if the temperature inside the freezer rose. Even if everything looks completely normal now… That small detail tells you something important. Because food that thaws and then refreezes isn’t always safe to eat. And without this trick, you’d have no way of knowing.
It’s simple. But once you’ve used it and understood how much it helps, it’s the kind of habit that’s hard to skip before your next trip.