When and How to Defrost a Freezer

Ice does not build up on its own; it comes from moisture that gets inside. Every time the door is opened, moisture in the room air enters, condenses on the cold surface, and remains as frost. Food put in while warm or uncovered, loose lids, and a worn gasket let more moisture in. So when a freezer frosts up often, start by checking the cause: is the gasket intact, does the door close completely, and are the packages sealed? As long as the cause remains, defrosting will have to be repeated every few months, and the same work will have to be done again each time.

The thickness of the ice layer determines when it is time to defrost. When the ice is more than five to six millimeters thick, it means an insulating layer has formed between the walls and the air inside; the appliance runs longer to reach the same temperature, electricity use increases, and the usable space on the shelves shrinks. A door that no longer closes completely or drawers that are difficult to open are also signs that the same threshold has been crossed. No-frost models handle this themselves, so manual defrosting is not needed; if ice builds up in one of them, the problem may be the gasket or a clogged drain channel.

Start by arranging a place for the food. Defrost the freezer when it is as empty as possible, in other words, when stock is low. Put the packages you take out in a cooler bag or a thick insulated container supported with ice packs; when they are all together, they keep one another cold. A balcony is not a reliable place in winter because its temperature is not being measured. This is also a natural opportunity to review the inventory: do not put expired or unidentified packages back, and rewrite the list of what remains.

Unplug the appliance, leave the door open, and wait for the ice to melt on its own. Towels on the lower shelf and a wide tray at the bottom collect the meltwater. To speed things up, you can put a container of hot water inside, close the door, and wait a few minutes; the steam loosens the ice. The things not to do are clear: do not chip the ice with a knife, screwdriver, or hard spatula; do not pour boiling water over it; and do not direct a hair dryer at it. Puncturing a refrigerant line ruins the appliance, and repair often costs nearly as much as a new appliance.

After all the ice has melted, wipe the interior surfaces with warm water and baking soda, dry them with a cloth, and check the drain hole. Plug the appliance in and run it empty; wait until it reaches the target temperature, and only then put the food back. Packages placed in a lukewarm freezer freeze slowly, undoing everything just gained. When putting them back, move the oldest-dated packages to the front; this also helps organize the time until the next defrost.