How to Defrost a Freezer

Freezer ownership saw tremendous growth in 2020, as homebound consumers looked for extra appliances to store food during lockdowns at home. At that time there was also a fear of shortages and an increasing interest in cooking at home as restaurants and takeaways remained closed.

Freestanding freezers were especially popular with consumers looking for extra space for food storage. According to Euromonitor, over 98% of UK homes have a fridge or fridge-freezer.

The Frozen Food Report 2021, issued by the British Frozen Food Federation (BFFF), states that:

• Frozen food has attracted over 400,000 more shoppers in the last two years.
• The retail frozen food market is now worth £7.1 billion and has added nearly £850 million worth of sales since 2019, that’s value growth of +13.5% and volume growth of +9.2%.
• A 19.8% growth rate has been recorded in sales of savoury frozen foods since 2019, with plant-based products up 16.8%.
• Shopping patterns continue to flex in response to changes to government guidance on working from home, social distancing and the reopening of pubs and restaurants.
• Frozen fish purchases have increased by £141.2 million in just two years.

With the total grocery market broadly flat, frozen sales have significantly outperformed the market. The figures, according to BFFF Chief Executive Richard Harrow, show that “consumers have truly fallen back in love with their freezers.”

How often should a freezer be defrosted?

How often you should defrost your freezer will depend on what type of freezer you have. Some guidelines recommend that you should defrost your freezer just once a year, others suggest twice a year, or on an “as needed” basis, when a frost layer of around 7 mm (1/4”) has formed, whichever is soonest.

Many freezer models will have a red plastic tag – the defrosting guide – sticking out of the inside wall of the freezer. If this red plastic tag is covered with a layer of frost, then the freezer needs defrosting. However, individual models of freezers and fridge-freezers may have different components, so the manufacturer guidelines will set out when they recommend that you should defrost your freezer.

Why should you defrost a freezer?

Refrigerators and freezers work by continuously evaporating and condensing a refrigerant gas along the pipes embedded inside them. As this gas evaporates, it absorbs the heat from the fridge’s or freezer’s compartments, making a cold environment.

Frost formation will have adverse effects on your freezer’s cooling performance. Whilst a thin layer of frost in your freezer may seem harmless, it can reduce the performance level of your freezer by hampering the evaporator’s job of heat transfer. The thick frost will prevent the evaporator from absorbing heat in the freezer properly.

The food stored in the freezer must be kept below a certain temperature. Over time the ice build-up in a freezer, even those that have auto-defrost functions, will make it harder for the freezer to maintain the right temperature, potentially affecting how long you can store individual items.

Defrosting your freezer will help your freezer to last longer, cost you less in energy, provide more storage space and also your food will taste better, as it can actually get freezer burn in a frosted icy freezer.

Although it is not essential, it is a good idea to clean your fridge-freezer or freezer while it is defrosted and empty, as it is much easier to clean.

Another benefit that you can gain from defrosting your freezer is that it gives you the chance to check the contents. Use this opportunity to label and date your frozen food and to bin anything that is out of date. Whilst freezing food allows you to keep it for much longer, over time, the colour, flavour and texture will start to deteriorate, making it less pleasant to eat, even though the food may well still be safe to eat.

Your freezer’s manufacturer’s guidelines will provide recommended food storage times for your freezer’s make and model, but if you can’t locate it, then click here for a comprehensive guide to how long you can keep food in the freezer.

How to defrost a freezer

It is a really good idea to plan your freezer defrosting well in advance so that you can ensure you have used up and not replaced as many of the contents as you can. Emptying a less than half full freezer is much easier.

Before you start, check the freezer manual for any dos and don’ts recommended by the manufacturer. Some appliances have defrosting settings and all kinds of other handy features to help you out. If you can’t find your manual, try googling the make and model of your freezer; most manufacturers publish a downloadable version online.

Next, preparation. You need to prepare the area around the freezer as there will be excess water.

You will also need the following:

• Towels.
• A sponge.
• A spatula.
• Washing-up gloves.
• Baking trays or washing-up bowls to catch the water.
• A bowl of hot water.
• A cool box big enough to fit in all your food from the fridge and freezer.
• Ice packs/blocks.

Before taking anything out of the freezer, put on your washing-up gloves to prevent getting an ice burn. Ice burns can be just as serious and as painful as any other type of burn. If you do get an ice burn, immediately run the affected area under cold water for 20 minutes then pat it dry and wrap the injured area with cling film to keep the burn clean.

Remove all items from the freezer, including food, any shelving and ice trays. If you have a fridge-freezer, remove all items from the fridge section too. Pile the towels inside and beneath the freezer. If your appliance has drain holes, make sure that these are not obstructed and you can place baking trays or washing-up bowls by these to catch the water.

Unplug the appliance and simply wait for the ice to melt. If the freezer is so frozen that the removable parts such as shelving, drawers etc. are frozen in place, remove these as they loosen up during the defrosting process.

To speed up the process even more, you can place a bowl of boiling water inside the freezer while it is defrosting and replace it as it cools. Place each bowl onto a thick towel, as excess heat from the bowl might cause serious damage to the inner surfaces of your freezer. The heat from the steaming water will get the ice melting.

You can also take off chunks of ice as it defrosts with the help of a plastic or silicone spatula. For the best results, make sure you heat the spatula first in hot water.

DO NOT use a knife, as this might damage the freezer walls and you could injure yourself if the knife slips. Never pour hot water into an ice-covered freezer compartment, as this could cause damage to the unit and the risk of scolding is high.

There are also a variety of proprietary freezer de-icer products on the market; simply spray the de-icer, leave for 5‒10 minutes and then scrape away with your spatula to remove the ice.

DO NOT, however, use car windscreen de-icer to defrost your freezer, as the contents are not safe for use with food.

Defrosting mats, usually used to help meat defrost quicker, placed in the freezer can also help to speed up the defrosting process. These mats are made of a metal such as aluminium that is a good heat conductor, which means it heats up and cools down quickly. If you don’t have defrosting mats, you could heat damp tea towels in the microwave and place these on the ice to melt it.

Another firm favourite to help speed up the defrosting process is using a hairdryer; you must, however, move the hairdryer around so that no one area gets too hot. Blow hot air at the side of ice accumulations, as the quickest way to move the ice is to get the air behind it.

You must also make sure that you take safety into consideration when using an electrical appliance near water. Try to keep the floor as dry as possible, take care not to drop the hairdryer anywhere near water and keep the flex dry.

Once you have totally defrosted your freezer and before you replace your frozen foods, thoroughly clean the freezer and any shelves or drawers.

You can do this by using a proprietary freezer cleaner, or just as easy wipe over with a solution of water and bicarbonate of soda – 1 tablespoon of bicarb to 1 litre of water. Then ensure that the freezer and shelves or drawers are completely dry before putting them back into the freezer.

Plug your freezer back in and allow it to run for at least an hour with the door closed to bring it back to the correct temperature before filling it again.

How to keep the food frozen

If you don’t have a spare freezer or a kind friend or neighbour with space in their freezer to store your food whilst you defrost your freezer then you will need to ensure that your food is kept at the optimum temperatures to guarantee its safety.

Most harmful bacteria will grow at temperatures above 8°C and below 63°C; this is known as the “Danger Zone” for microbial growth. The priority should be to keep frozen foods frozen at or below 0°C whilst you are defrosting the freezer.

If you are using a cool box or cool bag, then pack the frozen foods as tightly as possible and use ice packs/ice blocks to help keep the temperature low. Cool boxes are generally more effective than cool bags when it comes to insulation.

Some electronic cool boxes can be effective for as long as 24–48hrs; again, you will need to check the manufacturer’s instructions for your particular cool box, as every make differs. You also need to make sure that you keep your filled-up cool box away from sunlight and radiators.

If you don’t have a cool box or have more frozen food than fits into your cool box, there are other alternatives to help slow the thawing process. Choosing a freezing cold winter day for your defrost is ideal as you can place the food into a cool box, cool bag or even a large plastic lidded container and leave it outside until you are finished. You really need the temperature outside to be below 5°C and keep it away from any direct sunlight.

If you are unable to safely keep food frozen during your defrost, you could batch cook meals to freeze once the freezer is defrosted. Whilst you should not refreeze thawed food, you can cook it and then refreeze it. If you can’t keep your food sufficiently cold for the duration of your defrost, then you either need to cook it or throw it away.

During a very quick defrost you can wrap frozen foods in several layers of paper and keep them in a cool place; however, the inevitable rise in temperature will shorten their storage life.

How long does it take to defrost a freezer?

Depending on the freezer you have, and how much frost/ice build-up there is, defrosting your freezer can take anything between 2 hours and 24 hours to defrost naturally. That time can be cut if you use any of the methods mentioned above to help thaw the ice. However, you will also need to factor in the time it takes to empty, clean and reload the freezer.

What is the quickest way to defrost a freezer?

The quickest way to defrost a freezer is to use a steamer. A handheld steam cleaner is agile, lightweight and powerful. It delivers a stream of superheated steam exactly where it’s needed, making it perfect for defrosting and cleaning a freezer. Another benefit of using a steamer is that it is also a great way of cleaning as you defrost. Steam doesn’t just remove ice, dirt and food, it also kills bacteria. The social media cleaning star Mrs Hinch recommends this method.

Another really quick way to defrost your freezer if you have a wet-dry vacuum cleaner, is to use the blow function to direct warm air at the ice and the suck function to remove meltwater.

What is the easiest way to defrost a freezer?

The easiest way of defrosting your freezer is by just unplugging it, propping open the door and letting the ice melt naturally. You can do this overnight, catching water on the baking trays or washing-up bowls and letting the towels soak up the rest.

How to defrost a freezer compartment in a fridge?

If your fridge has a freezer compartment rather than a separate freezer section, you will need to empty the entire fridge including shelving before defrosting. Leaving the icebox to defrost naturally can take up to 2 hours so it may be preferable to use any of the defrosting methods outlined above to quicken the process.

How to defrost a freezer without unplugging it

If you can’t easily reach the plug to unplug the freezer, or if you have a fridge-freezer model, you can turn down the freezer section’s adjustable thermostats, if it has them, and leave the freezer section door open, then apply any of the defrosting methods outlined above. Once defrosted, don’t forget to reset the thermostat.

Final thoughts

Defrosting the freezer is one of those jobs that we all tend to put off as long as possible because of all the disruption it can cause. However, not defrosting your freezer is costing you more in energy; the more ice in your freezer, the more energy it uses.

Frost build-up in freezers can also cause its doors to jam, which can damage the appliance and affect the temperature you are supposed to keep your food at for hygiene and safety reasons. The more often you defrost the freezer, the less time-consuming the process will be.