What can and cannot be frozen?

The freezer is the most underused appliance in most kitchens, largely because people have been burned by one thing that came out unrecognisable and concluded it does not work. The rule behind which foods survive is simple once you know it.

Safety

Step by step

1. Understand the mechanism.Water in the food forms ice crystals that puncture cell walls. On thawing, those cells release their water, so the food goes limp and weeps. Anything whose quality depends on cell structure suffers; anything already broken down does not.
2. Freeze cooked dishes with confidence.Stews, curries, soups, bolognese, chilli, pies, lasagne, cooked meat. These have already been broken down by cooking and are often better after freezing because the flavours have had time.
3. Freeze bread, cake and pastry.Bread freezes excellently and toasts straight from frozen. Cake freezes well unfrosted. Raw pastry and raw biscuit dough both freeze and can be baked from frozen.
4. Freeze raw meat and fish properly.Both freeze well if wrapped tightly to keep air out. Portion before freezing — a solid block is an obstacle rather than an ingredient.
5. Blanch vegetables before freezing.A brief boil then straight into iced water stops the enzymes that would otherwise degrade colour and flavour in the freezer. Most vegetables need this; onions, peppers and herbs do not.
6. Know what fails badly.Salad leaves, cucumber, raw potato, whole tomatoes, soft fruit meant to be eaten fresh, cream-based and egg-based sauces, mayonnaise, custard, and cooked pasta on its own — all collapse, split or go grainy.
7. Know the partial cases.Milk separates but recombines with shaking and is fine for cooking. Soft cheese goes crumbly but works in cooking. Double cream freezes better whipped than liquid. Yoghurt splits but is fine in smoothies.
8. Never freeze eggs in the shell.The contents expand and crack the shell. Beaten eggs freeze fine, and yolks need a pinch of salt or sugar or they turn gelatinous.
9. Work around the failures.Freeze the sauce base without the cream and add it on reheating. Freeze the filling without the pastry lid. Freeze potato cooked and mashed rather than raw. The component that fails is usually addable later.
10. Freeze fast and in the right packaging.Fast freezing makes smaller ice crystals and less damage. Spread things thin, use the fast-freeze setting if there is one, and exclude air — freezer burn is dehydration, not a safety problem.
11. Portion and label everything.Contents and date. An unlabelled container is a decision nobody makes, and it stays in the freezer for two years.
12. Thaw in the fridge.Overnight, in the fridge, in a container. Thawing at room temperature puts the outside into the risk zone while the middle is still frozen.

Tips

• Freeze things flat in bags. They stack, they thaw far faster, and they use a fraction of the space of tubs.
• Freeze leftover wine, stock and coconut milk in ice cube trays. It converts an awkward part-used tin into a usable ingredient.
• A freezer works most efficiently when reasonably full. Bottles of water fill gaps and hold the temperature during a power cut.

Common mistakes

• Freezing something to rescue it — Freezing pauses bacterial growth rather than reversing it. Food that was already past its best comes out of the freezer exactly as it went in.
• Freezing a cream sauce — The emulsion splits and comes out grainy. Freeze the base without cream and stir the cream in when reheating.

If it doesn't work

Questions people ask