A frost-free freezer is designed to prevent one of the most common problems which bedevil such a device, and in particular one which is heavily used – as a freezer is designed to be.
An appliance which claims to be frost-free is designed to prevent the water vapour which enters the main compartment liquefying, and, after the freezer door has been closed again, and the temperature drops, forming into ice crystals which gather on the packaging or the surface of the food therein.
The problem with frost
The frozen water which has accumulated is what’s known as frost, and it can form in large quantities on packets if it is not removed. Not only this, but this ‘snow’ which then forms on all the packets of food in the freezer can severely restrict its capacity unless it is removed. Doing this, however, is time-consuming, so the best solution is to prevent the frost from forming in the first place.
If the frost remains in the freezer for a substantial length of time, it will eventually become ice. This restricts the freezer’s capability, and means that it has to use more power to store food at the low temperatures required to keep it edible and fresh.
Anyone who has owned a freezer for a number of years will know what has to be done next – and it isn’t a short or an easy task. The build-up of ice has to be removed, and is best done by switching off the freezer at the mains, and letting the ice melt, gathering it in bowls or using absorbent cloths, and then disposing of the water which is left.
A frost-free freezer includes a small fan heater inside it. A couple of times a day this heater is activated when the temperature drops below a certain level, and this then melts away the thin layer of frost which has formed since the fan was last activated.
The cost of frost free
The activation of this fan brings about one of the most obvious drawbacks of a frost-free freezer, in the shape of the extra power which it consumes to keep it free of ice.
And when the fan kicks in, it will also melt a thin layer of ice covering the surface of all the packets of foods being stored in the freezer. This means that the temperature of the food will rise very slightly – not an issue if you have had the food in the freezer for some time, but this can become a problem if items of food have recently been placed in the freezer and are being cooled from ambient temperature.
Over a long period of time, this is not an issue, and a frost-free freezer can even keep many food items frozen for longer than is possible with a freezer not equipped with this facility.
However, a frost-free freezer can cause problems with meat which is typically shrink-wrapped. The plastic covering affords little, if any, protection from the long-term build-up of ice and, in turn, certain amounts of this thawing every time the auto-defrost function kicks in. If this happens repeatedly, the frozen meat can develop ‘freezer burn’, which is a deterioration of the outer layer of the meat which you’ll definitely notice when you eat it.
So if you’re planning to keep large quantities of meat, or items such as ice creams which might stay in your freezer for a long time, a non auto-defrosting freezer is the better option. Again, though, the efficiency of the operation of a frost-free freezer will depend heavily on the quality of the material with which it is insulated – and that’s a subject you should take up with your electrical retailer when you’re choosing a new appliance.