Guide to Microwave Cooking
What are Microwaves?
Based on the principle of radar, microwaves are a form of energy that comprises electro-magnetic, short-length, non-ionising, high-frequency radio waves at the top end of the radio band. They are close to infra-red rays but not as powerful and the frequency is 2450 megahertz (MHz), which translates into literally millions of cycles or vibrations per second. The word 'hertz' comes from Heinrich Hertz, the scientist who first discovered the nature of the waves.
Inside the cavity of a microwave oven, with its extraordinary number of compulsory cut-outs and safety devices, the microwaves are completely confined and are unable to leak out and attack you. In any event, microwaves are an altogether different kettle of fish from X-rays, gamma-rays and ultra-violet rays, which are ionising and known to cause dangerous cellular alterations to the body with minimal or no temperature change.
Microwaves have none of these effects and, more importantly, are non-cumulative. Leaks can occur only if the oven is worn, damaged or mishandled, and for safety reasons it should be checked from time to time by a qualified engineer to make sure the door fits snugly, the seal around the door is secure, and the hinges are not rusty.
If the door front fractures, stop using the oven at once and request a service call as soon as possible. So what would happen if one were, briefly, exposed to microwaves? The answer is a burn, which is never pleasant. Therefore look after your oven, keep it serviced and clean it regularly.
Since the mid-seventies, microwave cooking has become part and parcel of your busy everyday life and given me more flexibility and freedom in and out of the kitchen than you ever imagined possible. Speedy, cool, hygienic, reliable and undemanding, the microwave works like a charm, cooks like a dream and uses only minimal electricity, a major consideration in times of rising energy costs and the need to make savings where we can.
It is an accepted fact that microwave ovens cannot completely replace conventional ovens and hobs but they do go a long way towards it. Used to full capacity, a microwave can become the most efficient, valued and respected piece of equipment in your kitchen, and your intention in writing this book is to put together a package of innovative recipes in addition to old favourites, proving that a wide range of dishes can be microwaved successfully. you have sometimes given an alternative method of cooking some of the ingredients used in a specific recipe to save time, or suggested finishing off a dish under the grill (broiler) to crisp skin or brown a topping. In these instances, your microwave will work in perfect harmony with your conventional oven.
Some dishes are not at their best if given the microwave treatment. Yorkshire pudding collapses. Pancakes fare no better, though they reheat to perfection. Soufflés and éclairs fail with irritating predictability. Meringues just about work but take so long you might just as well bake them conventionally and have done with it. And deep-frying is taboo because it is impossible to control the temperature of the fat or oil.
Some people still regard the microwave as something to use only for defrosting and reheating. A pity, because they're missing out. Many grow to love microwave cookery and soon come to understand and appreciate its seemingly magical properties ... Over to you.
How Microwaves Cook Food
When the microwave is plugged into a socket, the door closed and oven switched on, microwaves are emitted from a magnetron (or microwave energy generator) usually on one side at the top, protected by a cover, generally plastic. The microwaves are transmitted into the inside of the oven cavity down a channel called a waveguide, bounce off the sides and 'beam' on to the food from all directions. Instantaneously, the food absorbs the microwaves, which cause the water molecules within the food to vibrate.
The result is excessively rapid friction that creates enough heat to cook food. For a simple demonstration of how friction makes heat, rub your hands together vigorously and feel how warm they become. Now imagine this multiplied umpteen times and you will understand how the microwaves work.
For even cooking, most models are fitted with a wave stirrer, stirrer blade or paddle (concealed at the top) which helps to distribute the waves. Most also have a rotating turntable so dishes do not need turning during cooking. However, turntables do restrict the shape and size of dishes, so consider buying a model where the turntable can be switched off or removed if necessary.
Successful Microwave Cooking
Because microwaves are short-length, high-frequency radio waves, they are able to penetrate only 2.5 cm/1 in of the food in all directions. Thus shallow containers are better than deep ones except those used for some cakes and puddings that need headroom for satisfactory rising. Round dishes give the best results, followed by oval. Sometimes food in rectangular or square dishes cooks unevenly, especially at the corners.
The food will also cook more effectively if thick pieces are arranged towards the outside edge of the dish and not piled up. Stirring during the cooking cycle helps to distribute heat and, where practical, this has been recommended in the recipes. If possible, whole potatoes and other similar-sized foods (apples for example) should be arranged, on a plate or in a dish, in a hollow triangle, square or circle. If your microwave is an older model without a turntable, make sure you turn the dishes several times during cooking.
Resting and Standing Times
For heat to penetrate the food and work its way gently from the outside to the centre, it is recommended that the food be allowed to rest and stand after or during cooking. Some dishes, especially large quantities, turkeys, etc., if cooked without a rest, would become overcooked on the outside but remain undercooked in the middle.
Depending on what is more convenient, food may be left to rest or stand inside or outside the microwave. Individual recipes give guidance on resting and standing. As a further precaution, it is preferable to return an undercooked dish briefly to the oven rather than add extra time initially. The microwaves act so swiftly that even a few too many seconds could spoil the food.
As salt toughens microwaved meat, poultry and vegetables, it should be added half-way through or at the end of cooking. Other seasonings, such as herbs and spices, may be added at the beginning.
Never operate the oven while empty because without food or liquid to absorb the microwaves they will bounce straight back to the magnetron and shorten its life span. Similarly, melting 5–10 ml/1–2 tsp of fat, or heating just a tiny amount of liquid, will have the same effect, so it is best to place a cup or tumbler of water in the oven at the same time. Just in case it gets switched on by accident, it is a wise safety measure always to keep a container of water inside an empty oven until it is needed for cooking.
Suggestions for cleaning have been given in Hints and Tips. As fresh food spills are so easy to remove from the cool interior of a microwave (nothing burns on in the conventional sense), a wipe over with a damp cloth immediately after use will ensure that it stays spotless and fresh.
Metal containers reflect microwaves away from the food and prevent it cooking so metal containers or tins (pans) of any sort should never be used in the microwave. It is also important to note that crockery with metal trims or with the manufacturers' name or pattern design printed in gold or silver underneath could cause arcing – an effect like tiny flashes of lightning. This arcing not only damages the magnetron but also ruins the metallic decorations. The exceptions here are small amounts of foil used to cover poultry wing tips and ends of legs to prevent scorching, and metal kebab skewers that are well covered by the surrounding food.
However, you must ensure that the skewers do not come into direct contact with any part of the oven interior.
In order for the microwaves to reach the food and subsequently cook it, the dishes chosen should be made of materials through which the microwaves can pass most readily – like rays of sun through a window pane. These are listed below and, although most stay cool or even cold, some kinds absorb heat from the cooked food and feel hot to the touch. For comfort, the cookware should be removed from the oven using oven gloves.
These may be used for brief reheating of rolls, etc. Prolonged spells in the microwave cause dryness and cracking.
Clingfilm (plastic wrap) is excellent for covering and lining dishes.
To prevent the film from ballooning up in the oven and bursting, or being sucked back on to the food (the latter is a disaster if it happens to a pudding that is supposed to rise), you have recommended puncturing the film twice with the tip of a knife to allow steam to escape. By puncturing, you mean making a small slit and not a tiny pin-prick.
Not your best crystal but Pyrex-type glassware is ideal. Corning ware, which is ceramic glass, is also excellent. Other, sturdy, glass may also be used.
Kitchen towel or paper napkins may be used to line the oven base if food is to be cooked directly on it (paper is a great absorber), and also to cover food to prevent spluttering.
Use only rigid plastic; yoghurt or cottage cheese containers or thin plastic may collapse. Look for special microwave utensils made by firms like Lakeland or other reliable makes stocked by specialist kitchen shops, supermarkets and department stores. Note that plastic spatulas are useful as they can be left in, say, a sauce during cooking to use for stirring when required.
Pottery and Porcelain
Both may be used – but not your best china. Avoid dark utensils and ironstone as they absorb heat and take it away from the food.
Roasting bags, also called boiling bags, have a hundred and one uses; see-through plastic roasting bags are convenient to use and also clean. They are ideal for cooking joints of meat or poultry. Close the tops with elastic bands or string, not metal ties.
Waxed Paper Products
Like basketware, these dry out in the microwave and should be used only for brief reheating.
Like basketware, wood dries out in the microwave and should be used only for brief reheating.
Browning dish: this is a white ceramic dish, the base of which is coated with a special tin oxide material. It becomes very hot indeed when preheated, making it possible to sear food prior to microwave cooking. This gives the food the browned finish associated with conventional grilling (broiling) or frying (sautéing). As the dish needs to be preheated, empty, for varying lengths of time depending on the food being cooked, be guided by your own microwave oven instruction book.
As a general rule, the preheating time should be around 6 minutes for steaks and chops and 2–3 minutes for eggs. It should never be preheated for longer than 8 minutes, nor used in a conventional oven. If you are cooking in batches, the browning dish will need cleaning and preheating for half the initial length of time between batches. Although it will take on a yellowy tinge when hot, the dish will return to its original colour when cool. Preheating this type of dish does not harm the oven.
Temperature probe: this looks like a thick knitting needle attached to a plastic-coated lead and is generally available with the more sophisticated models of microwave ovens to register the internal temperature of food. One end slots into the side of the oven while the sharp end is inserted into the food to be cooked.
The cooking cycle is therefore geared to temperature and not time and when, for example, a joint of well-done beef registers 160°C, the oven will switch off automatically. As every model varies, please refer to your own microwave book before using the probe and setting the temperature.
Thermometer: thermometers for use in microwave ovens are now obtainable and, like temperature probes, they must be used according to the manufacturers' instructions. Never use a conventional meat thermometer in a microwave, although it can be used to test the meat for doneness when the joint is resting after cooking.
Choice of Microwave Ovens
People often ask me which model you would recommend and you always find this a difficult question to answer. Those who are not technically minded will do best with a fairly basic model that is straightforward to operate and does its job efficiently. Others might find the new models a joy in that they bear some relation to computers and can be easily programmed and manipulated to suit all purposes.
The only advice you can give on the selection front is to suggest a visit to your electricity supply retail store or a department store to have a thorough look at as many ovens as you can and ask for a demonstration. You will then be in a good position to buy what suits you, not what looks fabulous, is very expensive and turns out to be more to cope with than you bargained for.
Most domestic microwave ovens vary between 500 and 850 watt output.
All recipes in this book have been prepared in a 650 watt output oven, and usually use only two power settings: Full, which is 100 per cent power (650 watts), and Defrost, which is 50 per cent (325 watts). If your oven has a different output, the guide below may prove useful. Be warned: if you have a higher wattage output oven, make sure you do reduce cooking times and check a little before the end of your calculated cooking time. You can always cook for a few seconds more.
For a 500/550 watt output oven, increase the cooking time by about 20 per cent, e.g. 10 minutes becomes 12 minutes.
A 600 watt output oven will be much the same as a 650 watt one.
For a 700 watt output oven, decrease the cooking time by about 20 per cent, e.g. 10 minutes becomes 8 minutes.
For a 850 watt output oven, decrease the cooking time by about 30 per cent, e.g. 10 minutes becomes 7 minutes.
Using these figures will give a fairly accurate conversion time but for greater accuracy refer to your own microwave oven recipe book. Note that some manufacturers call Defrost 30 per cent power. Check your manual if yours does and you have a 650 watt or less output microwave, in which case use Medium (50 per cent) power where a recipe calls for Defrost. If you have a higher output (650–850 watts), use 30 per cent power instead of Defrost.
There are now technically advanced microwave ovens with variable power settings ranging from 1–10 or from 1–5 . The variable settings enable some dishes to be cooked more slowly than others and some users find this advantageous, especially when making stews and casseroles. Some models have a system whereby the power comes on and off automatically; listen and you can hear it happening. Other models have an automatic reduction in output at the lower settings but this is silent.
Foods cooked in the microwave can look pale and insipid. Hence your inclusion of bastes for roast meat and poultry, a few shakes of soy sauce or a dusting of paprika, beef stock cubes for stews and casseroles, and icings (frostings) for cakes. you have also incorporated a number of other tricks – like using Red Leicester cheese for toppings instead of Cheddar. As you will find out when you make up the recipes in the book, none lacks colour.
Summary of Settings
Setting 1 (1) equates to 10 per cent of power output and is used to keep cooked dishes warm or to take the chill off cold ones. It is called either warm or low.
Setting 2 equates to 20 per cent of power output and is recommended for warming or very gentle simmering. It is called either warm or low.
Setting 3 (2) equates to 30 per cent of power output and is used for defrosting and simmering. It is called either defrost, medium-low, simmer or soften.
Setting 4 equates to 40 per cent of power output and is often chosen for defrosting, braising and stewing. It is called either slow cook, medium, low defrost, stew, simmer or braise.
Setting 5 (3) equates to 50 per cent of power output and is used for defrosting and also for simmering and stewing. It is called either medium, defrost, simmer or stew.
Setting 6 equates to 60 per cent of power output and is used chiefly for reheating cooked dishes, baking or simmering. This setting is called either reheat, bake or simmer.
Setting 7 (4) equates to 70 per cent of power output and is used primarily for roasting. It is called either medium-high, bake or roast.
Setting 8 equates to 80 per cent of power output and is also used for reheating and baking. It is called either reheat or bake.
Setting 9 equates to 90 per cent of power output and is used for fast cooking of vegetables in fat (i.e. when making a stew). It is called either medium-high, roast or fast reheat, or sometimes sauté.
Setting 10 (5) equates to 100 per cent of power output and is used for the majority of recipes in this book. It is called either full, high maximum or fast cook.
Even if you have a microwave with variable power settings such as listed above, do not try to convert your recipes, which were all cooked at Full or 50 per cent power.
Conventional reheating of meat and poultry, or keeping plates of food warm in a cool oven, can sometimes cause a build-up of bacteria, resulting in mild food poisoning. With a microwave oven, the action is so fast that germs have no time to breed, and the food stays fresh and moist without looking frayed round the edges.
Freshness of flavour and colour, plus retention of nutrients, characterise most foods cooked in a microwave oven. The foods also tend to shrink less, and cooking smells are reduced.
It is encouraging to know that when cooking in the microwave the electricity saved is between 50 and 70 per cent. Also no preheating is necessary and there is minimal residual heat in the oven cavity. It has been estimated that using a microwave is four times as efficient as conventional cooking because all the energy is directed to the food, with no 'overspill'.
Notes on Microeave Cooking Recipes:
Always check food is piping hot all the way through before serving.
When following a recipe, use either metric, imperial or American measures, never a combination.
All spoon measures are level: 1 tsp = 5 ml; 1 tbsp = 15 ml.
Always wash and peel, if necessary, fresh produce before preparation.
Adjust strong-flavoured ingredients and seasonings to taste.
Herbs are fresh unless otherwise stated. You can substitute dried for fresh, as long as the herb is not for garnishing, but halve the quantity stated in the recipe as they are more pungent.
Eggs are medium unless otherwise stated.
Never preheat a microwave.
Dishes used for cooking sandwich-type cakes, deep cakes, flans, quiches and tarts should be the same depth as traditional baking tins (pans).
Hints and Tips For Microwave Cooking
To warm jars of baby food, remove the metal lids. Cover loosely with kitchen paper. Warm jars one at a time on Defrost, allowing about 1½ minutes. Test the warmth before using.
To bring chilled cheeses to room temperature, warm on Defrost, allowing 15–30 seconds for every 100–175 g/3½ –6 oz. If the cheese still feels cold and too firm for personal taste, allow a few seconds more but watch carefully to ensure it does not start to melt.
Chicken and Turkey Livers
To prevent livers from popping during cooking, pierce each piece once or twice with the tip of a knife.
To extract more juice from citrus fruits, warm each piece on Full for 10–30 seconds (the time needed will depend on the size of the fruit). Allow to stand for 5 minutes.
To clean the interior of a microwave easily, dampen a clean cloth and heat on Defrost for 30–45 seconds. Wipe over the interior of the microwave, then dry with a tea towel (dish cloth). Do this frequently to prevent food spills and splashes from sticking. As an alternative and also to freshen the microwave, wipe over with a specially formulated microwave cleaner. If you like the smell of citrus, put a few slices of fresh lemon or lime into a bowl with 300 ml/½ pt/1¼ cups cold water. Heat on Full for about 3–4 minutes until boiling rapidly. Wipe the interior with a cloth followed by a tea towel. Glass cleaner is ideal for the outside.
To check if a specific container is suitable for use in the microwave, test by placing a glass of water into it and transfer both together to the microwave. Heat on Full for 1 minute. If the container becomes hot in this time, it is absorbing too much heat and an alternative should be used. Important: sometimes dishes in the microwave become too hot to handle with bare hands and therefore oven gloves should always be worn.
To refresh day-old rolls, place in a napkin-lined basket and warm through on Defrost for about 1–3 minutes, depending on the number and size of the rolls, until their surfaces feel slightly warm.
To rehydrate dried fruits such as apple rings, apricots and prunes without soaking overnight, put about 225 g/8 oz/11/3 cups washed fruit into a glass bowl. Just cover with water and bring to the boil on Full for about 5½–8 minutes. Cover with a plate and leave to stand for 10 minutes. Drain before using. You can use the soaking water for sauces or for stewing fresh fruit.
To plump up raisins, currants and sultanas (golden raisins), treat as for dried fruit, but reduce the cooking time to about 4–6 minutes on Full. Allow to stand for 5 minutes. Drain and thoroughly dry.
Ice Cream and Jellies
To soften ice cream and loosen jellies (not in metal tins or moulds), heat on Defrost for 45 seconds. Allow to stand for 2–3 minutes.
Lotions and Potions
To warm baby and beauty lotions, shampoos and hair conditioners before use, remove the caps and heat each container on Defrost for about 45–50 seconds.
To have frozen plate meals ready in advance, arrange cooked foods – such as meat and two or three vegetables – on individual dinner plates. Place meat, fish and dense vegetables towards the outside of the dish without piling up, then arrange smaller vegetables, pasta or rice in the centre. Coat with gravy or sauce. Cover with clingfilm (plastic wrap) and slit it twice. When ready to serve, reheat each plate individually from frozen, allowing 5–6 minutes on Full, depending on the dish. The food is ready when the base of the plate feels piping hot in the centre. Allow to stand for 3–5 minutes before serving.
To soften and extract more juice, follow the directions for Citrus Fruits above.
To improvise a ring mould, cover the outside of a narrow, straight-sided smooth tumbler closely with clingfilm (plastic wrap). Stand upright in the middle of any round dish.
To prevent the danger of steam rushing into your face, tilt any container away from you when uncovering.
To soften lumpy or hard brown sugar, put 225 g/8 oz/1 cup in a dish with half a slice of very fresh bread or a wedge of fresh pear or apple. Cover with kitchen paper and warm on Defrost for 1½ minutes. Alternatively, cover the surface of the sugar with a piece of wet kitchen paper before heating.
To melt syrups or honey that have become grainy and crystallised, remove the metal caps and warm the jars, individually, on Defrost for about 3 minutes, stirring once. Syrup in metal containers must be decanted into a microwaveable container before heating.