Getting the most from a freezer

Freezers in most homes contain a layer of identifiable food and a deeper layer of unidentifiable material that is eventually discarded.

What freezes well

More than people assume.

Bread, sliced before freezing so pieces can be taken as needed.

Milk, which separates and recombines when shaken.

Hard cheese, grated, which goes straight into cooking.

Butter.

Cooked rice and pasta, cooled quickly and reheated thoroughly.

Stock, reduced to save space.

Herbs, chopped in oil in an ice cube tray.

Wine and citrus juice in cubes for cooking.

Raw meat and fish, and most cooked dishes.

Fruit, which is ideal for cooking and smoothies though it collapses when thawed.

Blanched vegetables, and several unblanched ones such as onions and peppers destined for cooking.

What does not

Worth knowing to avoid disappointment.

High-water-content raw vegetables intended to be eaten raw — lettuce, cucumber, tomatoes for salad.

Most dairy with a high water content — soft cheeses, single cream, yoghurt — which separate.

Fried food, which loses its texture.

Egg in shell.

Anything with a high proportion of gelatine set, which weeps.

And anything already thawed once, which should not be refrozen raw, though it can be cooked and then frozen.

The system

What prevents the archaeological layer.

Label everything with contents and date, without exception.

Unlabelled frozen food is discarded, always, eventually.

Freeze flat in bags where possible, which saves enormous space, freezes faster and thaws faster.

Flat packages can be filed vertically rather than stacked.

Portion appropriately, since a large block that must be thawed entirely is used less often than portions.

Keep a list on the door or nearby, updated when things go in and out.

This sounds excessive and is the single change that most improves freezer use.

Rotate, putting new items behind older ones.

Remove air from packaging, since freezer burn is dehydration caused by contact with air.

The temperature and the physics

Worth knowing.

A freezer should run at around minus eighteen degrees.

Freezing quickly produces smaller ice crystals and less cell damage, which is why thin packages and not overloading with warm items at once produce better results.

A full freezer is more efficient than an empty one, since the frozen contents help maintain temperature — filling gaps with containers of water is a genuine technique.

And food does not become unsafe in a working freezer; it deteriorates in quality, which is what the recommended storage times reflect.

Thawing safely

The food safety point.

Thaw in the refrigerator, which is slow and safe.

Cold water in a sealed bag, changed regularly, is faster.

Microwave defrost immediately before cooking.

Thawing at room temperature allows the outside to reach temperatures at which bacteria multiply while the centre is still frozen, and is not recommended.

Cook thoroughly, and do not refreeze raw food that has thawed.

Batch cooking

Where the freezer earns its place.

Cooking double and freezing half costs almost no additional time and produces a meal for a day when there is none.

The dishes that freeze best are stews, curries, soups, sauces, bolognese, chilli and anything braised.

Dishes with pasta or potato in them are better frozen without and combined on reheating.

A stock of four or five frozen meals removes the most common cause of unplanned takeaway.

If the freezer fails

The practical guidance.

Keep the door closed, since a full freezer holds temperature for a substantial period.

Food that still contains ice crystals can generally be refrozen, with some quality loss.

Food that has fully thawed and been above refrigeration temperature for an extended period should be discarded.

And an appliance thermometer inside, checked occasionally, gives warning of a failing appliance before the contents are lost.

Power cuts and what to do

A situation worth knowing in advance.

A full freezer, left closed, holds temperature considerably longer than a half-empty one, which is one practical argument for keeping it full.

The rule is not to open it, since each opening costs hours of holding time.

Food that still contains ice crystals and is at or below freezing can generally be refrozen, with some loss of texture.

Food that has fully thawed and warmed should be cooked immediately or discarded, and anything uncertain should be discarded, since freezing does not kill bacteria and a thawed product supports growth exactly as fresh food would.

A coin placed on top of a frozen cup of water tells you, on returning from holiday, whether the contents thawed and refroze while you were away.

General information only, not food safety advice. Follow official food safety guidance for your jurisdiction on freezing, thawing and storage times.