Preserving Techniques


Freezing is the most up-to-date and simplest way of preserving both cooked and uncooked foods, and the one that best retains their original flavour, texture, appearance and nutritional value. In the freezer food is stored at — 18°C (64°F) or lower. Ideally, garden produce should be prepared and put into the freezer immediately it is picked but if delay is unavoidable it should be kept in cool conditions; wrapped or covered and stored in the refrigerator is best. Pick when young and small and in perfect condition.

Packaging material

Packaging material must be strong to prevent damage, moisture-proof to keep in liquids and prevent others entering, vapour-proof to prevent the transfer of flavours or aromas, to prevent dehydration and to stop oxidation, which spoils the colour and breaks down nutriments, non-toxic so they do not support growth of bacteria or moulds, and must not become dry or brittle in the cold of the freezer. Starting with the cheapest, the following are suitable:

Polythene bags

Minimum thickness is 120 gauge but 150-250 gauge are stronger, better for longer storage and easier to re-use.


Special freezer film is easy to mould round any shape to exclude air. Thinner film can be used to wrap several items to be overwrapped together.

‘Boil-in’ food bags in which food can be frozen and then dropped into boiling water to reheat.

Aluminium foil

Used much as plastic film with a freezer grade for extra protection. Do not wrap acid fruits in such a way that they are in contact with aluminium foil.

Rigid containers in a wide range of shapes and materials including foil, waxed cardboard and plastic, some with their own covers and others to be covered by plastic film or foil. It is always important to exclude as much air as possible. With bags gather neck close to food, insert a straw into bag and suck out air until bag forms round contents. Remove straw and fasten with tie. In containers 1-2.5cm (½-1in) headroom should be left especially when there is liquid, as this expands as it freezes. Extra space can be filled with crumpled plastic film. Labelling should be done before freezing and should record the kind of food and variety, quantity or weight, date, and notes for thawing and cooking or reheating.

Quantities which can be frozen at one time

Refer to the instruction book supplied with the freezer. The usual recommendation is a tenth of total capacity in each 24 hours. For example, each cubic foot (0.028cm) holds approx. 11kg (25lb) of food; a 4 cubic foot (0.11301 m) freezer will hold approx. 45 kg (100lb) so freeze only up to 4.5kg (10lb).

07. June 2013 by admin
Categories: Tips and Advice | Comments Off on Preserving Techniques


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