For this reason, you should always put a coin in your freezer

The Coin Trick and Smart Appliances—Do They Mix Well?

Many appliances are today accompanied by temperature monitoring and alert systems. For example, a smart freezer will have an alert system to remind you when the temperature shoots above a certain level through your phone. The whole system, however, still depends on internet connectivity as well as power supply to be reliable, thus limiting their reliability during an outage or disaster.

The coin-in-the-freezer trick has no dependence on technology. Thus, it is one foolproof backup. So even if your smart appliances lost their connection, this coin will give you clear signals that the contents in the freezer were compromised. Together, both methods combine for a layered approach at monitoring food safety.