Freezing

At −18 °C, bacteria and enzymes practically come to a standstill – which makes freezing the gentlest way to keep food for a long time, without any additives. Vitamins are largely retained; they suffer more from time spent in the fridge than from the cold. For families, the freezer is a stash of half-prepared meals that makes many convenience foods unnecessary.

What freezes well: bread (sliced, so you can toast slices individually), cooked dishes such as soups, stews, bolognese or curries, berries, bananas for smoothies, herbs in ice cube trays with a little water or oil, raw meat and fish, and vegetables that you blanch for two minutes first (dip briefly in boiling water, then plunge into iced water). Less suitable: lettuce, cucumber, tomatoes and raw potatoes (they go mushy or sweetish), eggs in their shells, cream sauces (they separate) and yoghurt.

Guideline storage times from Germany's Federal Centre for Nutrition (BZfE): vegetables and fruit 6 to 12 months, cooked dishes about 3 months, beef 9 to 12 months, poultry 8 to 10 months, oily fish 2 to 3 months, bread 1 to 3 months. Nothing becomes dangerous after that, but flavour and texture deteriorate. Freezing food flat (in bags or shallow containers) speeds up freezing, keeps the cells intact – and means it thaws faster later.

The safest way to defrost is in the fridge, not at room temperature; put meat in a dish so that no thawing liquid drips. Cooked food can go straight from the freezer into a pan or the oven. Never refreeze anything raw once it has thawed – but once it's cooked, it's fine to freeze it again.

A tip to stop things getting forgotten: write the date and contents on every bag, and every few weeks have a “freezer day” when you only cook from your stocks.