Kafka’s book goes beyond anything written before on the subject, including, emphatically, owner’s manuals. It is the first book that shows serious cooks how they can find a microwave oven indispensable–for preparing components of complicated dishes–as well as showing harried cooks how microwave ovens can speed getting dinner on the table. Kafka does not make the usual claims that the microwave oven can do everything–no albino roasts, vinyl-like baked potatoes, or tan rubber brownies. Instead she maps out what it can do that nothing else does so well or so fast: cook vegetables, grains (polenta, my old favorite, comes out perfect), broths, pates, and jams, among many other unexpected foods. She breaks with most manuals and books by, for example, pronouncing that breads and conventional cakes are disasters. She finds most manufacturers’ defrosting programs, with their elaborate alternations of medium and low power, unnecessary; full power for a short time usually produces the same result. As for defrosting steak: “Don’t do it.” Most important, and most unlike other authors of books on microwave cooking, Kafka is an original and stylish cook, whose recipes would taste delicious no matter what they were cooked in.
A “dictionary” at the back of the book gives cooking times for most of the foods mentioned as ingredients in the recipes and for quite a few more, so that you can make up recipes of your own. The nature of microwave cooking requires precise timings and quantities; it does not forgive the abandon of effervescent improvisers, the way a stove often does. Unfortunately, different ovens cook in different ways, depending not only on how much power they generate but also on how they diffuse microwaves, and volumes of ingredients–say, chicken parts–vary everywhere. And every cook has his own idea of when something is done. So expect to make your own refinements in the cooking times and container sizes called for.
If you have not yet bought a microwave oven, I recommend that you buy a full-powered one–between 600 and 750 watts. I bought a medium-powered one–500 watts (small ovens are usually 400 watts)–and have found the difference in speed when using full-powered ovens so remarkable that I plan to buy one. I hear from people who test microwave recipes that some 500-watt ovens cook many foods nearly as fast as 700-watt ovens, but mine doesn’t. They also tell me that performance varies within brands from model to model, and that the only way to know that you will have the speed of a full-powered oven is to buy one.
I have gone from refusing houseroom to a space-saving oven to considering keeping two, even though I know that in large ovens it is possible (if tricky, because of timings) to cook two dishes at once, using a rack. Once you start cooking in a microwave oven regularly, you use it to cook components of one or more dishes, just as you would a stove, and you want to be able to cook several things at once. Whatever size you buy, pay the extra amount for a keypad that will allow you to time your cooking to the second. Dial controls are not precise enough for most recipes, and you’ll often want to put something in for only twenty or thirty seconds more.
Just as word processors cannot do the writing for you, microwave ovens can’t eliminate preparation time. I will admit that as obvious as this lesson seems, it came as an unpleasant surprise. The vegetables still have to be peeled, the onions chopped, the spices retrieved from the back of the cabinet. The prospect of a good, satisfying dinner in ten minutes is hard to realize if you insist on using only fresh foods. But a microwave oven brings that prospect a lot closer almost no matter what you’re making–and delivers it when you’re cooking fish.
Fish cooked in a microwave oven is the single best example of how owning one can change your life. First, fish needs no preparation. You take it out of the wrapping paper and put it on the plate you plan to serve it on. It needs nothing to make it taste good: no oil, no court bouillon to poach it in, no herbs you forgot to buy. Even a fish as bland as sole reveals itself to be much more interesting than it was when poached in a liquid that drew off its flavor or baked at a heat that dried it out. The inside and the outside of the fish cook at the same time (unless the fish is more than three inches thick), eliminating the problem of a raw center and a dry exterior. No more undercooked fish served in the fear of being caught serving dry fish. The appearance barrier doesn’t exist: fish isn’t supposed to brown unless it’s fried or broiled, in which case it’s probably overdone. It looks good white (and even better on a dark-colored plate), and it is snowy when it comes out of the microwave oven. I used to buy fish only rarely, despite my great fondness for it, out of reluctance to take the time to figure out how best to cook it and for how long. Now I buy any fish that I can find, knowing that I will taste it at its best after a few minutes. And I’ll have only the plate to wash.
Most kind of fish take the same time to cook in the microwave oven and call for the same technique. What determines cooking time is the weight and the shape of the fish. Although it might seem cumbersome to weigh pieces of fish (or translate the decimal weight on the package into ounces), doing so ensures proper cooking, and is easier than standing a ruler beside the thickest part of the fish and bending down beside a counter to decide what it measures–the prerequisite for the “Canadian” rule of cooking fish for ten minutes per inch of thickness. The Canadian rule is inexact from the start, because a steak might be an inch thick from one end to the other whereas a whole fish or fillet might be an inch thick in the center but very much thinner at the sides or ends; it also doesn’t take into account any liquid that may have been added, which can make a great difference in timing.
Although whole fish that aren’t bigger than your oven can be cooked in it with great success, I’ll give rules for fillets and steaks, because they are more widely available in markets. Kafka defines fillets as “halves or quarters of fish removed lengthwise from the bones,” and steaks as “cuts across the fish with or without bone.” Flat-boned fish such as flounder, sole, and perch are sold either whole or in fillets; big, thick fish such as swordfish and tuna are nearly always sold as steaks, and salmon often is. Leaving in bones and skin will not affect cooking times for fillets and steaks.
Fillets should be cooked on the smallest plates they can fit on in a single layer; a rectangular dish will suit several fillets. If the fillets have skin, slash it across the width of the fillet, so that the fish does not curl. If the steaks have tapered ends, place these pointing toward the center of the dish. Food at the edge of a dish receives moremicrowaves than food in the center, so anything thick or slow-cooking should always be placed along the rim.
Cover the fish tightly with plastic wrap. Wrapping stabilizes heat and moisture around the food being cooked, and helps to counteract the uneven pattern of microwaves in every oven–a defect that turntables remedy only incompletely. (You can buy a wind-up plastic turntable if your oven doesn’t come with one, or remember to rotate dishes that take more than five minutes to cook a quarter turn midway through cooking.) As the tightly covered food cooks, the plastic forms a dome over the dish, making it look like a terrarium, and as the dish cools, the plastic shrinks to encase the food, like Cryovac.
It may be tempting at first to imitate conventional cooking methods, such as poaching or steaming, but the most effective microwave cooking can be disconcertingly simple. For instance, any liquid beyond a teaspoon or two, which quickly turns to steam, will only slow cooking. A half cup of liquid will add about thirty seconds to cooking time, depending on the depth and width of the dish. A small amount of vegetables-less than half a cup–won’t affect the cooking time, if you scatter them around the fish rather than over it. A cup, or six ounces, will add a minute in a full-powered oven, a minute and a half in a small oven. If you want to add more than half a cup of slow-cooking vegetables, such as carrots, green beans, whole or quartered onions, or broccoli, precook them for a minute or two. (These measurements apply to liquid and vegetables added to the whole dish, not to each portion.) Quick-cooking vegetables, such as mushrooms, scallions, zucchini, and chopped onions, can be cooked with the fish.
The flavor of dried herbs is intensified in the microwave oven, so use less; because there is so little liquid to absorb it, use less salt; and pepper becomes so strong that you should add only a little at a time until you become used to the new gauge. The flavor of fresh herbs weakens, so add a bit more or add them just before the dish finishes cooking.
You can nearly always eliminate fat from any recipe you want to adapt to the microwave oven. If you do want to add it, a spoonful of olive oil or melted butter (nothing is faster or easier for melting butter than a microwave oven–see why you need two?) drizzled over the fish just before it is served will taste fresher and stronger than if cooked.
Kafka’s dictionary gives cooking times for fillets and steaks of various thicknesses and in various portions. I’ll give her times for one and two portions, and bear in mind that you can’t double times willy-nilly for more. For fillets a half inch thick and weighing six to eight ounces each, the time for one piece is two minutes or in a small oven three and a half minutes; for two pieces, two and a half minutes or in a small oven four minutes. For steaks three-quarters of an inch thick and without bone, weighing eight to nine ounces each, the time for one piece is three minutes or in a small ovenfour and a half to five minutes; for two pieces, four to five minutes or in a small oven six to seven minutes.
Fish will continue to cook if left in the oven and especially if left wrapped. Be very careful when removing plastic wrap. The plate may be only warm, but the steam under the wrap is hot and strong, and it can easily burn you. Prick the plastic with a knife to let steam escape, and gently pull back one corner, keeping your hands to the side of the dish. After you bring the plate to the table, you might start wondering what you’ll try in the microwave oven next, and counting the number of dishes you won’t have to wash.
Despite my enthusiasm for microwave ovens, I have been unable to persuade my entire acquaintance to buy them, and not only because of the counter-space problem. Friends worry that they aren’t being told about health dangers, and especially if they have children around, they don’t want to take an unknown and thus all the more frightening risk. No one to whom I spoke at the Food and Drug Administration’s Center for Devices and Radiological Health seems willing to corroborate their suspicions.
Przemyslaw Czerski, a physician and research biologist at the center, whose field is non-ionizing radiation and health protection and who has written a book on the biological effects of microwaves, says, “From the point of view of safety, particularly with children, I certainly prefer a microwave oven to a gas range, which will have boiling things that could be upset over a child.” (He does caution a mother heating her baby’s formula in a microwave oven to wait a minute until the formula stops heating, and then to shake the bottle and feel a drop on her wrist before giving it to the child; a cool bottle may hide a too-hot liquid.) Czerski says that within the emission limitations that the FDA currently requires of all microwave ovens, there are “no known experimentally proven or theoretically feasible health hazards, from what we know about the interactions of microwaves at this frequency range with living systems.”
Czerski is speaking of emissions of microwaves from ovens; microwaves leave no radiation in food. Another misconception he hastens to correct is the one caused by the frequent reassuring statements that television picture tubes emit more radiation than microwave ovens do. Picture tubes emit ionizing radiation (the kind x-rays emit) and microwave ovens emit non-ionizing radiation (the kind light bulbs and most household appliances emit); the two are not comparable.
Joanne Barron, the chief of the microwave and acoustics section of the office of compliance at the FDA’s Center for Devices and Radiological Health, says that microwave ovens manufactured since 1976 have over their lifetimes held to the emissions requirements for microwave ovens fresh from the factory (the requirements, enacted in 1971, allow for slightly more leakage after the ovens are bought). The FDA also requires two interlock devices preventing theoven from producing microwaves when the door is open, and a monitor that will blow the oven’s fuse if for some reason both of the devices fail and the door is opened.
Louis Slesin, the editor of Microwave News, recently published the results of a report at the Fermi National Accelerator Laboratory, in Batavia, Illinois, that found that leakage tends to increase with ovens‘ age, but that their interlock systems ensure leakage only at extremely low levels and very rarely at ones above the FDA standards. Slesin, whose newsletter deals with broadcast towers and video-display terminals much more often than it does with microwave ovens, thinks that both the short-term risk (of any part of the body being heated) and the long-term risk (of any ill effects of chronic exposure, none of which have yet been identified) to those who use microwave ovens at home is negligible, and he praises the FDA for enacting the “only enforceable non-ionizing radiation standard in the country.” This standard has brought justifiable confidence to consumers, he says. He does fear that workers who are exposed to microwave ovens in continuous use for hours every day may be in some as yet unspecified danger, and he is frustrated that “no one” is conducting studies of chronic long-term exposure.
The only risk that Slesin can imagine for children is that of staring, transfixed, at food through the window of the oven, where any leakage is greatest; the eye’s lens has no cooling mechanism, as most of the body does, and a child might develop cataracts. This is, he says, at the moment a scare scenario. If you don’t want your child staring into the oven, cover the door with something opaque, and if you want to minimize your own exposure, step back a few feet from it–exposure decreases geometrically with distance. Slesin, in short, cannot work up much concern about the home use of microwave ovens. He is not one to shy away from bringing consumers bad news that manufacturers don’t want them to hear, either–he publishes another newsletter about the dangers of non-ionizing radiation from video-display terminals.
Kafka’s book has itself raised other fears. Manufacturers of cookware and ovens are up in arms over her contention in four recipes (of 600 in the book) that it is safe to deep-fat fry in microwave ovens; they claim that flawed cookware can break, that people can burn themselves from splattered oil, and that oil can heat beyond control and catch fire. Kafka counters that cooks should check to be sure that containers are properly large and are free of cracks, chips, crazing, or mending and that her book both calls for small amounts of oil in deep containers and warns against attempting to deep-fat fry in small ovens, whose interiors might be too low to avoid splatters. She says that she has heated fat for thirty minutes in the microwave oven–twice as long as she recommends in any recipe–without having it surpass 385 degrees. The standard temperature for deep-fat frying is about 350 degrees; oil reaches the smoke point at about 475 degrees, at which point it will give an off flavor to food, and it can ignite at about 600 degrees. Both the smoke and flash points of oil are significantly lowered when oil is contaminated with water, and all food contains a lot of water; if you decide to try deep-fat frying in the microwave oven, be sure to use only fresh oil every time you do. However deep-fat frying is done, it is potentially dangerous (let alone nutritionally unacceptable), and manufacturers seem more concerned about hurt and possibly litigious customers than about damage to their ovens.
For similar reasons, manufacturers of plastic wraps call for consumers to vent wraps when covering food to be cooked in the microwave oven, by leaving open a small area at the edge of a dish. Kafka calls for unvented wrapping. Dr. Gertrude Armbruster, a teacher at the College of Human Ecology at Cornell University who specializes in microwave cooking, says that consumers “are worried when they see plastic wrap balloon” but that in her years of covering foods tightly with various kinds of plastic wrap she has never seen it burst from steam pressure, a danger that manufacturers hold out. Again, the danger manufacturers seem to fear most is that of consumers being burned, in this case by steam.
A possible hazard that no one has yet raised in the popular press is that of the leaching of chemicals from plastic wrap into food when the wrap is used in microwave cooking. The plastic wrap that works best by far for microwave cooking is polyvinyl chloride (PVC), which clings most tightly to containers. Unfortunately, the “reservoir of chemicals that could migrate into foods” is “much higher” in PVC wrap than in other kinds, according to Dr. Gregory Cramer, a chemist at the Food and Drug Administration who works on the regulation of plastics and new packaging. Those chemicals are plasticizers, which give PVC wrap its flexibility. There are fewer chemicals that could migrate from polyvinylidene chloride (PVDC), the basis of Saran Wrap, or polyethylene (PE), the basis of Glad Wrap; these resins require either less or no plasticizers to be flexible. Reynolds, the best-known manufacturer of PVC plastic wrap, says that its plasticizers have all been approved by the FDA; but the FDA’s regulations for plasticizers in plastic wrap were devised primarily for use at room temperature and below in the 1960s, when microwave applications were not envisioned. Migration takes place at the highest levels when plastics are in direct contact with fatty foods, which absorb chemicals much more efficiently than water condensing beneath the wrap used to cover a dish. The amount of chemicals that migrates depends not only on the nature of the plastic but also on how long the plastic is in contact With the food and at what temperature. For the moment, the FDA is not actively investigating the issue of plasticizer migration from plastic films in the microwave oven.
But as for the safety of using microwave ovens themselves, I could not elicit even a shadow of concern from either Czerski or Barron, at the FDA. When I asked Czerski if he used a microwave oven at home, he said, “The control panel on my microwave oven is broken, and I’m terribly upset that I have to live a few days without it.”