How to freeze vegetables including broccoli, cauliflower, mushrooms, etc.
As with large quantities of fruit, freezing seasonal vegetables, in particular, is an excellent method of preservation, which allows many vegetables to be stored for up to a year in the freezer without much loss of, colour, flavour or nutritional value.
The best results when freezing vegetables will be obtained when using the freshest vegetables possible, preferably being frozen shortly after harvesting, if you have your own vegetable patch or piece of land for growing vegetables.
As soon as vegetables have been picked, they deteriorate very quickly, especially at high temperatures and therefore it is important to freeze them immediately or refrigerate and then freeze them within 12 hours of harvesting, to ensure that valuable nutrients are not lost.
Some types of vegetables are highly unsuitable for freezing and these mainly include green salad vegetables such as cucumber, lettuce, cress and radishes.
Similarly, other vegetables may be frozen but upon defrosting there will be some change in the texture and quality, making them unsuitable for some people to freeze. These include celery, whole tomatoes and new potatoes.
If you plan on storing your vegetables for several months in the freezer it will be necessary to blanch them first. This involves immersing them in fast-boiling water or steaming them for a specified amount of time, depending on the size and type of vegetable and then plunging them into ice-cold water before draining and packing.
Blanching the vegetables before freezing impedes enzyme action during storage time in the freezer and this means that the deterioration of the vegetable is kept at a minimum and that vegetables will emerge from the freezer in the same condition as they entered.
Blanching green vegetables such as broccoli or beans is particularly effective, as this seems to improve and enhance their flavour, making for a delicious meal upon cooking.
Certain more solid vegetables will need to be blanched for longer than others. Following the details on blanching vegetables are instructions on how to prepare a number of popular vegetables for freezing, how long to blanch them for and how to package them for storing in the freezer.
How to blanch vegetables
- Half-fill a large pan with water and bring to the boil until it is boiling rapidly.
- Place 1 lb of prepared vegetables into a wire basket and gently lower into the boiling water.
- Once the water begins to boil again, start timing (different vegetables have different boiling times).
- Remove the basket with the vegetables from the boiling water and plunge into ice-cold water to stop the cooking process. It is possible to over-blanch vegetables, which will result in the actual cooking of the vegetable and a loss of nutrients, flavour and texture. Under-blanching is just as undesirable for other reasons, and therefore care must be taken to ensure that the timing and blanching of the vegetables is carried out exactly as instructed.
- Drain the vegetables and then pack as instructed in either polythene bags or plastic containers, label the packaging and place into the freezer.
Remove the outer leaves and stalk of the artichoke and trim the top. Also remove the choke and you should be left with the heart. Wash in cold water and then blanch for 7 minutes. Immerse in cold water and pack in rigid containers. There is no need to leave any headspace room. Store for up to 10-12 months in the freezer.
Wash the asparagus spears in water and trim the stems and woody parts with a sharp knife. Sort into thick and thin spears and trim to the same size in length. Blanch thin spears for 2 minutes and thick spears for 4 minutes. Immerse in cold water, drain and pack in rigid containers. Alternatively, tie into bundles and wrap with aluminium foil. Freeze for up to 10.12 months.
Beans (green, broad, runner)
Wash the beans in cold water. Shell broad beans and trim the ends of runner and green beans. Blanch for 3 minutes. Cool in cold water and drain. Pack into polythene bags.
Remove the outer leaves and woody parts from the vegetable and wash in salted water in order to remove insects. Cut the broccoli head into smaller pieces and blanch for 3 - 5 minutes depending on size. Immerse in cold water and drain. Pack in plastic containers.
Remove the outer leaves from each sprout and wash well in cold water. Sort into sizes. Blanch small sprouts for 3 minutes, medium-sized sprouts for 4 minutes and large sprouts for 5 minutes. Plunge into ice-cold water, drain and pack in polythene bags.
Select young crisp cabbages for best results. Wash thoroughly and then shred finely. Blanch for 2 minutes maximum. Immerse in cold water and pack in polythene bags.
Remove the tops of the carrots and then wash and peel them. Small-sized carrots may be left whole. Cut larger carrots into cubes or strips and blanch for 2 minutes. Blanch small whole carrots for 5 minutes. Allow to cool in cold water, drain and pack into polythene bags.
Remove outer leaves and wash thoroughly. Divide into small-sized florets. Blanch in water containing the juice of one lemon for 3 minutes. Immerse in cold water, drain and pack into polythene bags. Freeze for up to 6 months.
Remove the outer leaves and trim the base. Wash thoroughly and then cut into 1½ inch lengths. Blanch for 3 minutes. Cool and drain. Pack in polythene bags or plastic containers filled with some of the blanching water, leaving a slight headspace.
Wash the courgettes and trim the ends off. Cut into ½-inch slices. Blanch for 1 minute, immerse in cold water and pack into rigid containers.
It is also possible to fry the courgette slices lightly in butter, allow to cool and pack.
Do not wash the mushrooms but instead wipe them clean with a damp piece of kitchen paper.
Slice large mushrooms but leave smaller ones whole and then sauté in melted butter. Allow to cool and pack in plastic containers.
Alternatively, steam whole mushrooms for 5 minutes and sliced mushrooms for 3 minutes. Cool and pack in plastic containers, leaving a small headspace. Freeze for up to 3 months.
Wash the parsnips, trim the ends and peel. Cut them into slices, quarters or dice them. Blanch in fast-boiling water for 2 minutes. Immerse in cold water and drain. Pack into polythene bags or plastic containers.
Shell the peas and blanch for 1 minute. Immerse in cold water and pack into polythene bags.
Only freeze small new potatoes whole. Blanch them for 4 minutes, cool in cold water and pack into polythene bags.
Potatoes give best results when prepared as chips and cooked first. Wash and peel the potatoes. Cut into chips. Deep-fry in hot fat for 3 minutes, drain on kitchen paper and cool. Pack into polythene bags and freeze.
Wash spinach and trim off woody parts and stalks. Blanch for 2 minutes, drain and squeeze out excess water. Allow to cool and pack in plastic containers, leaving ½-inch headspace.
Tomatoes are best frozen as a purée or juice.
Purée: Wash tomatoes and immerse in boiling water for 1 minute to loosen the skin. Peel and core the tomatoes then simmer for 5 minutes. Pass through a sieve or put through a blender. Allow to cool and pack in plastic containers, leaving room at the top for expansion.
Juice: Wash the tomatoes, core and cut into quarters. Simmer in a saucepan for 5 - 10 minutes. Pass through a sieve and add 1 tsp of salt per 2 pints of juice. Cool before packing into rigid containers. Allow room for headspace.
Use frozen tomatoes within 6 - 8 months.
Follow instructions for parsnips. Swedes are also prepared in the same way.