This is a really useful idea

From Brightside:

Sometimes when we’re away from home, the power goes off and we never know about it. However, this can cause food stored in the freezer to defrost and deteriorate.  To find out if these food items are as frozen as you left them, use this simple trick before leaving home: fill a cup with water, and put it in the freezer. When it’s frozen, place a coin on the top, and return it to the freezer.

If you find a coin at the bottom of the cup when you come back after a long vacation you should toss all the food immediately. It means that the power was out for enough time for your food to melt and re-freeze. If the coin is on top, it means that there was no power failure, and your food is as good as when it went into the freezer. If the coin is in the middle, it means that the power went out for a short period of time and most of your food items are probably still fresh.

There’s more at the link.

That’s so simple, I can only wonder why I never thought of  it myself;  yet I never did.  D’oh!  I’ll be doing it from now on, though.  It’s a good idea not just during a long vacation, but even if you’re gone all day.  Some freezers won’t keep food frozen for that long.



  1. Something else to think about: The colder you keep your freezer, the longer food stays good – and the longer it takes to thaw in a power outage.
    I keep my freezer as cold as it will go without icing up the fridge – it is currently about 0 and virtually anything stays good for months (if wrapped properly to avoid freezer burn).
    I've had 2 day power outages where the food stayed frozen solid. Also, freezers use less energy and keep food cold longer if they are mostly full. You can keep bottle of water or ice packs in it to be ready when needed and to keep it full – remove them if you need the space (freeze plastic bottles upright with space for the water to expand; I find 32 oz Gatorade bottles work great).

  2. I remember my father doing a similar trick with string in the week before we went on our annual summer vacation, back in the days well before automatic ice makers. He would freeze a length of knotted string in an ice cube and the morning we left, tie the string to one of the wire shelves in the freezer. If the ice cube was still hanging there when we returned, all was well.

    Before I had an alarm system that logged power (see below) I did a similar trick with an indoor-outdoor thermometer. The indoor unit will display temperature inputs from as many as 4 weatherproof sending units, and track minimum and maximum temperature from each of those "channels." I placed one of the sending units in the freezer and one in the fridge so I could tell what happened in our absence.

    A quick Amazon search turned up several thermometers that record minimum and maximum temperatures, many under $20 or so, that could be placed in the fridge and/or freezer. I've got one – Accurite, $24 on Amazon – on my fridge that wirelessly monitors both fridge and freezer temps, records min and max, and can be set to sound an alarm if preset max temps are exceeded. I doubt I could hear the alarm at the beach, however…..

    There are "failed circuit alarms" that plug into a 115 volt receptacle with a pass-through plug (a device, such as a fridge or freezer, can be plugged into the alarm's plug so one maintains the same number of outlets) which will screech like a smoke detector if power drops below a threshold (IIRC, about 80 volts) to notify that power has failed on one particular circuit. About $35-40 at Amazon.

    Many home alarm systems – which are dependent upon 115 volt house current to operate, even if they contain backup batteries to maintain operation during power outages – have the capability to notify homeowners if power fails. Some – such as Simplisafe – require paying for premuim notification services to send text messages to the homeowner, and will maintain a running online log of system events, including power outages. Others rely on the central monitoring station to call the homeowner, and some systems won't notify the central station until their backup battery power is nearly exhausted.

    Such a log may prove useful when dealing with utility companies for reimbursement for damages caused by power outages. It should be noted that inconsistent power delivery may do more than spoil food; modern appliances contain electronics that are susceptible to expensive damage from power drops and surges.

    As for simple loss of power, the computer industry has also provided solutions for this, albeit at somewhat increased expense and without the benefit of home security. There are devices that will monitor electrical power, frequently including hertz as well as voltage, and an internal auto-dialer will call a preset telephone number to notify that electrical power has changed to "out of desired range."

    Use something like e Kill-A-Watt to determine power draw on your fridge and/or freezer; modern appliances are sufficiently energy efficient that a large home Uninterruptible Power Supply (UPS) such as a 1500VAC unit from APC or TrippLite, can power a fridge for 30-40 minutes as well as provide protection against severe power surges. Amazon recently had a Gold Box deal for one at $129; I'd very much prefer to sacrifice a $129 UPS than a $2000 refrigerator/freezer with $500-$1,000 of food in it.

  3. Or, fill a plastic bottle half-full of water, lay it on its side in the freezer til frozen, then set it in the freezer upright.

    The configuration of ice when you return will indicate if it has thawed and refrozen.

  4. I've got thermometers that record min/max over time. I zero them out before I leave on a protracted absence and check them when I get home.

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