Freezing is now the most common method of food preservation, and comes into its own for medium term storage. As most fruit and vegetables are some 90% water, the propagation of water crystals during the freezing process in the domestic freezer, can alter or destroy the texture of the fruit or vegetables. Commercially, they use “blast freezing”, which freezes the produce so fast that only smaller water crystals form. By turning down your freezer thermostat several hours before you intend to freeze the produce, or using a “fast freeze” setting if you have one, and only freezing small quantities at any one time, will improve your chances of an acceptable result. Even with these precautions, some vegetables will end up in a flabby, mushy state when they are thawed out for use, and in my view are therefore not worth the effort.
I would not bother freezing Runner or French Beans, Mange tout or Snap Peas, Celery, Bulb Fennel, Turnip, Tomatoes, Beetroot, Courgettes, Marrows, Parsnips. I know that some people do freeze the above vegetables and are happy with the results. Therefore, I have included indicative “blanching” times if you really want to try freezing these vegetables, though I feel that they are better used fresh.
Vegetables require to be Blanched before freezing, as soon as possible after picking. This destroys all bacteria and enzymes which cause the produce to start to deteriorate as soon as it has been picked. Only use good quality vegetables, cutting them into evenly sized pieces, no bigger than an egg.
Blanching vegetables with a Pressure Cooker. Insert the trivet into the Pressure Cooker, add 300 ml water, bring to fast boil. Lower the prepared vegetables into the Pressure Cooker, close the cooker with the lid set to Medium pressure and blanche for the time indicated. Immediately reduce pressure and plunge the blanched vegetables into running cold water, to prevent further cooking. When the vegetables are cold, drain them well before starting the freezing process.
Broad Beans (shelled), Broccoli, Cauliflower (firm only), Leeks, Peppers. 1 minute.
Peas (shelled), Courgettes, Morrow, Spinach, French and Runner Beans, Celery, Bulb Fennel,to pressure only.
Corn on the cob (remove husk and silks and leave whole), 3 minutes.
Blanching vegetables in a large, deep pan. Prepare the vegetables as indicated above. Fill the pan 2/3 full and bring to the boil. Completely immerse the vegetables, bring back to the boil, and blanch for the above times plus one or two minutes. Immediately cool in running cold water and drain before freezing, as before.
Fruit freezing. If freezing fruit whole, top and tail as necessary, wash, drain and pat dry with Kitchen paper. Open freeze them and then put them into a poly bag and seal. If freezing the fruit as a pure/e, put into a plastic container, but leave about 10 ml space before fitting lid. This space is required to allow for the expansion of liquids on freezing.
Soups. After cooking soups, place into your freezing container, replace the cover before cooling the temperature as quickly as possible in a water bath. Only then, put into the freezer.
Herbs. Herbs will retain their colour during the freezing process, which makes frozen herbs very useful for adding at the last moment of the cooking process to soups and cooked dishes.
The best method for me is to wash and then roughly chop the herbs in a processor before placing them in a thin layer in a freezer bag, prior to freezing them. After an hour in the freezer, take out the bag and roughly handle the bag to separate out the frozen herbs, before putting the bag back to finish freezing. This makes it easier to get out just the right amount of the herbs, when you are cooking.
Another method is to wash and pat dry the herbs and freeze in a poly bag. Roughly handle the bag and the frozen herbs will break up into smaller pieces, that you can use as necessary.
Alternatively, wash and chop the herbs and pack tightly into ice cube trays. Fill with water to brim, freeze and then put frozen herb cubes into poly bags and use as necessary.