Frequently Asked Questions About the Freezer Coin Trick
Does the type of coin matter?
No, not at all. Any coin will work because they are all denser than water and will sink. A penny, a dime, or a quarter will all serve the purpose perfectly. The key is simply to have a visible marker.
Can I just use an ice cube tray instead of a cup?
You can, but it’s often less effective. A small ice cube can melt very quickly, even if the freezer temperature only rises for a short time. A larger cup of ice provides a better buffer and a more accurate indication of a prolonged warming event. The greater distance the coin has to fall from the top to the bottom of a cup also gives a much clearer and less ambiguous signal.
How long does the power need to be out for the ice to melt?
This is a tricky question with no single answer. It depends on several factors: the starting temperature of your freezer, how full it is (a full freezer stays cold much longer than an empty one), the quality of its insulation, and the ambient temperature of your home. A well-stocked, well-insulated freezer might keep food safe for up to 48 hours without power. The coin trick doesn’t act as a precise timer, but rather as a physical record that a thaw—of some duration—did occur.
What should I do if I forgot to put a coin in my freezer?
Don’t panic. If you return from a trip and suspect a power outage but didn’t set up a coin, you’ll have to rely on other clues. Look for the signs mentioned earlier: an unusual odor in the freezer, soft or mushy textures in food that should be solid, ice cream that has clearly melted and refrozen, or stains from leaked juices. If you see any of these signs, it’s best to err on the side of caution. Remember the most important food safety rule: when in doubt, throw it out.
