All photos by Peter Cassidy
Preserve your harvest: how to freeze food
6th April, 2010
A simple guide to freezing fruit, vegetables and herbs from the book Grow Your Own, Eat Your Own
Freezing has a longer history than you may imagine; keeping food chilled is not such a modern invention. And the oldest naturally frozen food is still uncovered in the Arctic: deep-frozen mammoth is apparently still edible after tens of thousands of years.
The first mechanical freezers were invented by the Victorians and soon introduced on a domestic scale for the rich, and on boats for long-term transport of perishable goods. Freezing food at home has become easier with modern units, which are totally reliable.
They involve only a modest capital outlay, and a big one costs little more than a small one. A bigger freezer is so much more useful and more efficient per cubic foot, and only marginally more expensive to run than a small one.
A deep freezer is useful in many ways, not only for long-term storage from this cropping season till next, but also for the shortterm holding of a crop until it's convenient to deal with - or as a way of pre-processing. Many of my jams and syrups are made from briefly frozen fruit; once the fruit has been burst by freezing, the juice separates easily.
Bag it, box it or cup it?
During the productive season, whenever you prepare meals with your own fresh produce it makes sense to make too much, and then freeze ready-to-reheat portions, either of individual fruits or vegetables, or of whole meals.
For this, plastic cups are very handy; once frozen and well labelled the cups can be repacked in freezer bags. Although plastic boxes are most efficient when full and are easy to stack and move, their lids stick and are brittle, and they waste space as they become empty.
Plastic bags for freezing are sloppy, hard to keep in order, and need tying or closing with a clothes peg or wire tie to prevent them swapping flavours with everything else - although obviously one big plus point is that clear bags often need no label!
A combination of boxes and bags is most practical, with the bags moving inside suitable half-empty boxes. I save plastic drinks bottles, to wash and reuse for freezing juices, and wax cartons for the purées.
A very sensible idea is not only to label each item - with ID and date! - but also to compile a list detailing contents and position - for example ‘four bags raspberries, blue box, lower left-hand side, two bags strawberries plus half-box blackcurrants lower left-hand side, herbs all in green box upper right-hand side' - and attach it to the outside of the unit. It then makes sense to update the list as you either put in or take out items. Otherwise there is a tendency for stuff to 'go dormant' until it is past using with much comfort.
Most fruits are easy to freeze, needing no more than to be cleaned, dried, laid on oiled trays to freeze and, once solid, popped into labelled bags or tubs to be taken piecemeal as required. Ideally, any air should be sucked or squeezed out of bags.
Fruit portions can be dipped in sugared or even salted water to stop discoloration and the 'freezer burn' drying-off of their surface - make sure your trays are well oiled, though, as wet fruit is more prone to stick.
Alternatively, freeze them in portion-controlled amounts that have been sugared overnight to withdraw some of their juices. Or they can be frozen fresh, packed in sugar syrup or fruit juice, their own or another. Freezing mixtures ready for use will save you time later. Turning fruits into juices, ices and sorbets saves space and can mean even more get eaten.
The stone fruits need to have their stones removed before freezing, as these taint the fruit - and eventually everything else - with a flavour of bitter almond. Most skins are easier to remove after freezing and before the fruit is thawed; simply pass each fruit under hot water and the skin can be slipped off before the inside starts to melt.
Vegetables require more care if they are to be frozen: first of all they need to be not only cleaned and cut into small uniform bits, but also blanched. This is to disrupt their enzymes and help preserve some of their texture. Blanching is simply heating the items to boiling point, or near enough, for 3-5 minutes, and then immediately cooling rapidly in very cold, even icy water.
After cooling, drain, gently roll on a clean dry tea towel and then freeze on well-oiled trays before repacking into bags. Most useful for this simple method I reckon are sliced green beans, peas, broad beans and then sweet corn, which can be added to almost anything. Carrots and other roots can be sliced, cut small or cubed to make them a more even size before freezing.
Tomatoes and sweet peppers are both to be treated more like fruits, and frozen as they come - the tomatoes whole and un-skinned, or skinned and chopped; the peppers cleaned and cut into small chunks. Mushrooms can be frozen, but they dry and rehydrate so readily it seems pointless for most, though I have often successfully frozen fried giant puffball steaks.
The gourmet crops, such as asparagus and globe artichokes, can be blanched and frozen, but may as well be fully cooked first and then need only defrosting later. The tips and hearts are much more economical of space than the whole spears and heads! The soup and stock are even more compact, and worth considering even if you don't fancy freezing the titbits alone. With these gourmet crops it's a good idea to freeze them on oiled trays, and it's worth sealing them first under plastic film or oiled foil, to save the aroma permeating the freezer.
The problem that can arise with freezing onions and garlic, and anything containing much of them - as with other strong-smelling produce - is cross-taint. So beware and have good seals on everything. You do not get nice results freezing fresh garlic or onions - a bit unpleasant, in fact, though less so if they're blanched or fried first. Meals containing these alliums can be frozen, if well sealed, but it might be better to keep them out of stocks and bases specially made for freezing and to add them later, after thawing.
With some vegetables, a good alternative to blanching before freezing is to partially fry them first - this works well for battered onion rings and especially well for potato chips. For confirmed chip addicts like me this is the method to get real home-grown choice main-crop variety chips when the stored crop has long gone or sprouted and the new crop is still months away. Pre-frying is also a handy method for aubergines and courgettes. Needless to say, use only the best organic oils, or butter.
Another alternative is to make big batches of special bases for your favourite dishes - such as curries, tomato sauces for pasta, ratatouilles, vegetable stews, fruit compotes - using the basic ingredients, but possibly leaving out garlic and strong flavourings.
Herbs are not difficult to freeze fresh as they are so thin, but they can soon lose their flavour to everything else, so should be frozen in closed containers.
Most are more convenient to use later and store well if chopped and mixed into water, stock or oil and frozen in ice-cube trays, then repacked as ready portion-controlled chunks. Herbs should be double-packed, for example, in a sealed bag in a closed box, so they don't cross-taint - especially basil.
One specialised side of freezing is the frozen sweet. It is remarkably easy to make your own ice lollipops from real fruit juice. Shops sell plastic moulds - but any small plastic containers will do if given good handles. Fruit-juice ice cubes are even easier and a more child-friendly size.
Then there is the gamut of wonderful fruit sorbets and ices. All these are a delicious way of getting more fruit into your diet. The juice, preferably cold-extracted, mixed with sugar - and optionally egg white in the good old days - is stirred while being frozen. You take it out, whip it and put it back several times. This makes the most wonderful appetiser, dessert and treat - and it's pretty healthy if you ignore all that sugar!
This is an extract from Grow Your Own, Eat Your Own by Bob Flowerdew (Kyle Cathie, £14.99). Readers can buy the book at the special price of £12.99 inc free p&p (UK mainland only). To order your copy, ring: 01903 828503, quoting ref. KC GYO/ECO, or email: firstname.lastname@example.org.
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