How do I freeze food properly?

How to freeze food so it's still good when you defrost it — packaging, portioning, what freezes badly, and safe defrosting.

Difficulty: beginner
Time: 30 min
Read: 3 min
Safety: caution

Short answer

Freeze in portions you'll actually use, in packaging that excludes air, labelled with contents and date. Freeze fast and flat, defrost slowly in the fridge, and never refreeze anything that has been defrosted unless you've cooked it in between.

Freezer burn and disappointing texture come from two causes: air contact and slow freezing. Air dries the surface of frozen food; slow freezing forms large ice crystals that rupture cell walls, which is why some things turn to mush. Both are manageable with packaging and portioning.

Safety

Defrost in the fridge, in cold water, or in a microwave immediately before cooking — never at room temperature, where the outside reaches bacterial growth temperatures long before the middle thaws. Do not refreeze thawed raw food unless you cook it first. Once cooked, that dish can be frozen again.

What you'll need

Freezer bags or rigid containers
Permanent marker and labels
Baking tray for open-freezing
Vacuum sealer (optional)

Step by step

Cool food completely before freezing.Warm food raises the freezer temperature and partially thaws whatever is next to it.
Portion into the amounts you'll actually use.You cannot take half a frozen block. Portioning is the difference between a useful freezer and a full one.
Exclude as much air as possible — press bags flat, fill containers nearly full.Air contact is what causes freezer burn. Flat bags also freeze faster and stack better.
Freeze flat on a tray first, then stack once solid.Flat packages freeze quickly (smaller crystals) and store far more efficiently.
Label everything with contents and date, on the outside.Frozen food is unidentifiable. An unlabelled freezer becomes an archaeology project.
Open-freeze loose items — berries, chips, meatballs — on a tray before bagging.They stay separate, so you can take out just what you need.
Defrost in the fridge, allowing plenty of time.A large joint can take a full day or more. Plan ahead rather than leaving it on the counter.
Use frozen food within a sensible window — generally 3–6 months for quality.It stays safe indefinitely at -18°C, but texture and flavour decline steadily.

Tips

Freeze liquids like soup and stock flat in bags — they stack like books and defrost far faster than a block in a tub.
Freeze leftover herbs in oil in an ice cube tray, and the same with wine, stock or tomato purée.
Things that freeze badly: salad leaves, whole eggs in shell, cream-based sauces (they split), fried food (goes soggy), and anything with a high water content eaten raw, like cucumber.
Keep a list on the freezer door. It's low-tech and it's the only thing that reliably stops food being lost in there.

Common mistakes

Freezing in one large block — You can't take a portion, so you either defrost everything or nothing.
Leaving air in the bag — Freezer burn — dry, discoloured patches where the surface has dehydrated.
Defrosting on the counter — The surface sits at bacterial growth temperatures for hours while the middle is still frozen.
Not labelling — Unidentified frozen items get thrown away eventually. That's just delayed waste.

Questions people ask

Can I refreeze food?

Not raw food that has been thawed — but you can cook thawed raw food and freeze the cooked dish. Food thawed in the fridge and still cold can sometimes be refrozen with some quality loss, but the safe default is to cook it first.

How long does food last in the freezer?

Safely, indefinitely at -18°C. For quality, most cooked dishes are good for around 3 months, raw meat 3–6 months, and bread about 3 months.

Why does my frozen food taste stale?

Freezer burn from air contact, or absorbed odours from other food. Better sealing solves both.