/ Food & Drink, Home & Energy

To freeze or not to freeze? Your freezer myths busted

Ever wondered what you can and can’t freeze? When we opened up the debate on Which? Conversation, you had tons of suggestions – so we investigated some common freezing myths to separate fact from fiction.

Freezing food until you’re ready to eat it is one of the best ways of cutting your grocery bills and minimising the amount of food you throw away.

But if you’ve ever questioned whether it’s safe to eat the age-old tub of leftovers you’ve found at the bottom of your freezer, you’re not alone.

Freezer myths busted

There’s plenty of advice and hearsay around – from government guidelines to your grandmother’s sworn-by methods. With the help of Which? nutritionist and food expert Shefalee Loth and microbiologists at the Food Standards Agency, we got to the bottom of some common freezing myths:

1. Freezing food kills bacteria: False. Freezing food doesn’t kill all bacteria. Some are dormant during freezing, but can multiply as food gets warmer when it’s defrosting.

2. Frozen food keeps forever: True. Food can be safely frozen indefinitely. However, the taste and texture may deteriorate over time.

3. You can’t freeze or defrost rice: False. Rice can be safely frozen and reheated, as long as it’s cooled quickly after cooking – ideally within an hour. You can reheat frozen rice in the microwave until it’s piping hot. Don’t freeze take-away rice though, as you never know how long it’s been left out at room temperature.

4. Frozen fruit and veg contain fewer nutrients than fresh: False. Nutrients start to leak out of fruit and veg as soon as it’s picked. Commercially frozen produce is often harvested and frozen within hours, helping seal vitamins inside, whereas fresh fruit and veg can spend days in storage, transport and lingering on supermarket shelves.

Our food-freezing checklist

So here’s our safe freezing and defrosting checklist to help you navigate the freezing minefield:

  • Make sure your freezer is running at -18°C or lower.
  • Freeze hot food as soon as it’s cooled, ideally one to two hours after cooking.
  • Wrap food well or keep it in air-tight containers to prevent freezer burn (where air dehydrates food, affecting its taste and appearance).
  • Never re-freeze defrosted raw meat or fish unless you cook it first.
  • Make sure food has defrosted all of the may through before you cook and eat it.
  • Defrosted food will spoil in the same way as if it were fresh – try and eat within two days.

Your freezing tips

We asked you to share your food-freezing experiences in a previous Convo, and we were flooded with useful tips and suggestions. Commenter Sue said she never throws food out:

‘Leftovers are frozen for later. I make bread in my breadmaker, then cut it in half and freeze the halves. I freeze chopped leftover herbs – coriander, parsley and dill. I don’t freeze leafy vegetables apart from spinach – they never seem to be as good.’

Gogsy27 championed air-tight bags:

‘Meat lasts for ages in air-tight bags. Suck the air out of larger bags before tying them. Frozen veg – green beans, peas etc – are great in pasta dishes. Far cheaper than buying and wasting – just put in as much as needed towards end of pasta cooking!’

Lots of commenters agreed that stews and curries can taste better after they’ve been frozen for a while. According to Tilly:

‘Anything seasoned or spiced takes on a stronger flavour when frozen. No idea why, but the frozen stuff is always stronger tasting after defrosting and cooking!’

So it seems that plenty of people freeze all sorts of meat, fish, fruit and vegetables for months, and found that it tastes just as good as the day it was frozen. But what about the food that tastes awful once it’s been defrosted? Have you found any foods that you just can’t trust to the humble freezer?


I was recently advised to freeze a specialty bread in foil rather than plastic. It worked very well – as that cellophane type covering (on ciabatta) is useless unfortunately. It’s reusable too.

I have to say I am both surprised and delighted to learn that frozen food keeps forever. I’ve got a freezerful of old quickes, meals, etc, that I’m working my way through, and there are a fair few bits I’d have probably thrown away otherwise!

I think I was taught in Physics that boiled water freezes quicker than water drawn directly from the tap. It’s still not quick enough for emergency ice cubes though.

Oh, and I’m not sure if there’s any truth in this, but spicy food seems to get hotter when reheated after being frozen.

1. Freezing food kills bacteria: False. Freezing food doesn’t kill all bacteria. Some are dormant during freezing, but can multiply as food gets warmer when it’s defrosting.

This is rather misleading. ALL bacteria are dormant at freezer temperatures, which is why food can be safely frozen indefinitely. Freezing is one of the techniques used by microbiologists to store bacteria for long periods, so you can safely assume that freezing does not kill bacteria.

I would not rely on this, Jess. Whether bacteria survive freezing depends a lot on their environment and how rapidly the process occurs. Campylobacter species do lose viability more than most bacteria when frozen but I have read articles confirming survival when frozen.

I used to have an extensive stock of preserved bacteria in my lab but never worked on any organisms involved in food poisoning.

Interesting – All four facts I knew already – But then I taught Science and food technology for 35 years – and probably why I am never sick.

Alex says:
31 July 2012

Glad I already knew those!

I’ve got slightly obsessed with freezing fruit as a snack this week. Frozen blueberries are particularly lovely, and apparently if you slice up a banana, freeze it and then blend it, it takes on convincing ice cream texture.

Also, if you’ve got a big event coming up, you can often make and freeze cakes in advance very well. I have to say the crumbly ones don’t hold up so well, but dense mixes such as carrot cake do just fine.

I’m probably imagining this entirely, but seem to get better results with roasts if the meat’s been frozen first!

Ronald Alexander says:
5 August 2012

It is possible as ice crystles grow they force meat fibers apart, when the meat is thawed
the fibers are more relaxed.

janet says:
1 August 2012

Can you freeze blue cheese?

jadw says:
3 August 2012

Yes – I have done it successfully

Jaytee says:
3 August 2012

Why would you want to freeze it??? It literally lasts for months in the fridge!

It freezes fine, but it becomes a bit crumbly when defrosted again. You can, however grate frozen Stilton really nicely, and this works well if you pounced on a post-Christmas “reduced” offer at the supermarket and are making a cheese sauce with frozen cheese

Do not try to freeze broccoli and Stilton soup – for some reason the cheese takes on a really disgusting taste when reheated. Make broccoli soup, freeze leftovers and add fresh cheese when reheated.

sara harry says:
3 August 2012

when bananas are soft and black and no one will eat them. I turn them into banana and choc muffins or banana bread and freeze until required! i also freeze leftover meals for work! or pot up for my 2 year old son! no waste here

Nubestreet says:
3 August 2012

Ground coffee or coffee beans stay fresher in the freezer. The beans can be ground whilst they’re still frozen. I like putting stewed fruit into my porridge so I make a big batch, decant it into jars and then freeze them. I do the same with soup (using soup and sauce bags) so that I have a few week’s worth of lunches in the freezer. I once opened a bottle of wine and it was a bit too caustic to drink so I divided it into little pots and froze them for use later in coooking. It’s all gone now but my daughters love the frisson of taking their chopped apricots to school in a plastic pot marked ‘wine’!

Jaytee says:
3 August 2012

Re: freezing rice.

I’ve been doing it for years, and never had any problems. My method: I leave any spare rice in its pan until the following day, then transfer it to a bag or an old ice-cream tub and put it in the freezer. I fail to understand all this fuss about quick cooling: it’s simply unnecessary, probably thought up by those folk who sell you stuff to kill 99% of germs wherever you like!

Don’t do this Jaytee. Boiling rice will cause spores of Bacillus cereus to germinate and produce growing bacteria. When rice is kept warm or even at room temperature the bacteria will grow and produce a toxin. This is a well known cause food poisoning. See:

It is much safer to cool the rice quickly and freeze it.

Incidentally, killing 99% of bacteria is rather meaningless. Most bacteria are harmless, like most humans. You might be able to distinguish an armed psychopath from a friendly neighbour, but it is not so easy with bacteria.

DaveK says:
3 August 2012

Unlike the fridge try and make sure your Freezer is as full as possible.

Most food items contain lots of water hence they freeze well. A little known fact is that keeping water at less than -18c is cheaper in electricity than keeping air at -18c. A full Freezer costs less to run.

Also in the event of a power cut a full freezer will take longer to spoil.

TimB says:
7 August 2012

Regarding keeping your freezer full; as Which’s previous article stated “Our advice is not to bother, as opening the door of a freezer lets in only a small amount of warm air, which doesn’t take much energy to cool down. Anything that’s already frozen is unlikely to warm up either. So filling the freezer up isn’t likely to save you a penny”
I used plug in energy meter on our freezer. It uses around 30% less energy per week when half full than it does when full.

Upright freezers will use more energy and ice up faster if the door is opened frequently. Full shelves help avoid warm air replacing cold air when the door is opened, but drawers can do the same job without the need to the freezer full. Chest freezers are most efficient but are less convenient.

pickle says:
3 August 2012

If you like Vodka try keeping the bottle in the freezer, add chilled soda water and no need for ice cubes which water it down. Leftover rice is one of the worst foods to cause upset tummy, for some reason bacteria multiplies rapidly in it, that is why so many people who eat Chinese or curry after a boozy night get upset stomachs. Thanks for the tip about wrapping bread in foil, will try that

I have a cupboard full of old butter, ice cream, etc, tubs, much to everyone’s amusement, but I freeze all leftovers, never waste a thing, never ill. You just have to be sensible, don’t freeze anything that looks as though it’s at the end of it’s healthy life, and don’t leave anything lying about, put in fridge or freeze ASAP.

Bob Marcus says:
3 August 2012

Re freezing cooked rice.
We find that rice cooked for an evening meal is far too warm to put into the freezer until well into the night. We therefore pack it up and leave it in a cool place until morning.
We have been doing this for nearly forty years now and have never had a problem – perhaps we are just lucky. On the other hand perhaps people who grew up in the days before fridges were in common use tend to have a better idea of how to handle food safely.

I think you are right about being lucky, Bob. The problem is nothing to do with freezing rice but allowing it to remain warm or at room temperature. Once it is frozen it is safe to keep. Food poisoning from rice is a very well known problem (it is usually associated with vomiting) and I see that Pickle has mentioned it a couple of posts ago.

I can’t see why it takes so long for spare rice to cool sufficiently to freeze or at least put in the fridge.

Ernesyt Parott says:
3 August 2012

I save the plastic containers in which I get such things as Bicarb. or Bakoing powder to store sinhgle helping portions of Bolognaise or Chicken curry in the freezer

Cal C says:
3 August 2012

I have been cooking and freezing rice for many many years. Never had a problem. I always cook extra rice. Once I’ve dished it out, I put a little aside for my husband to have seconds, as I know he always will, then run the rest under cold water to cool right down. I then leave it to drain for a few minutes, put it in an airtight container and pop in the freezer. Simple!

Another tip, if you are cooking curry, it will always taste better the following day. Cook the day before needed, cool, store in an airtight container in the fridge overnight and enjoy the next day – make sure you reheat thoroughly.

I’m no food expert, just a retired special needs teacher, but I enjoy cooking.

Bob Marcus says:
3 August 2012

@ wavechange. It takes a long time to cool, at least partly, because we use a rice cooker to cook about six meals for two people and the cooker retains the heat for a LONG time. I don’t really like the idea of rinsing it in cold water after cooking but we do indeed pop it in the fridge if is sufficiently cool to package up before bed time.

Ah, now I understand, Bob. Why not empty the rice cooker straight after cooking?

I’ve made my comments with my microbiologist’s hat on, but there is plenty of evidence on websites to support my concerns. A long, slow cooling period is just what is needed to get these bacteria growing and producing toxins. B. cereus will probably not grow at all at fridge temperatures.

roy says:
3 August 2012

Making Sloe Gin, Always Freeze first. This some how improves the taste of Sloes. Ferment the sloes with the skins, and add the cheapest Gin 3lb. of sloes 3lb. sugar And 2 bottles of cheap gin. Strain and bottle. Just in time for Christmas.

Bob Marcus says:
3 August 2012

I don’t know about sloe gin, but as we always make cherry brandy with our morello cherries I’ll have to bear the freezer idea in mind.
We make a lot of jam with home grown fruit and find it easier and quicker to freeze the fruit first. The skins break down more easily and need less cooking. The only thing to remember is to use about ten percent more fruit than normal to compensate for the loss of pectin in freezing.

Brenda says:
3 August 2012

What about the instruction on packaged fresh food, including meat and fish, that reads “suitable for freezing on day of purchase. Use within one month”. Do we just ignore the “use within one month bit”?

Alfred Common says:
31 July 2013

I have frozen a M&S ready meal in error.Can it be defrosted and eaten safely

Does it say the ready meal can be frozen? If so, should be fine.

Most ready meals can be frozen, and the packaging will recommend a maximum time it can be stored frozen.

The taste and texture may change but food will not become unsafe to eat even if it is not nice to eat.