On Food And Cooking Part 29

Paralichthys californicus Paralichthys californicus

The Effects of Rigor Mortis and Time We sometimes eat fish and sh.e.l.lfish very fresh indeed, just minutes or hours after their death, and before they pa.s.s through the chemical and physical changes of rigor mortis (p. 143). This stiffening of the muscles may begin immediately after death in a fish already depleted by struggling, or many hours later in a fat-farmed salmon. It "resolves" after a few hours or days when the muscle fibers begin to separate from each other and from the connective-tissue sheets. Fish and sh.e.l.lfish cooked and eaten before rigor has set in are therefore somewhat chewier than those that have pa.s.sed through rigor. Some j.a.panese enjoy slices of raw fish that are so fresh that they're still twitching (ikizukuri); Norwegians prize cod held in tanks at the market and killed to order just before cooking (blodfersk, or "blood-fresh"); Chinese restaurants often have tanks of live fish at the ready; the French prepare freshly killed "blue" trout; and many sh.e.l.lfish are cooked alive. or "blood-fresh"); Chinese restaurants often have tanks of live fish at the ready; the French prepare freshly killed "blue" trout; and many sh.e.l.lfish are cooked alive.

In general, delaying and extending the period of rigor will slow the eventual deterioration of texture and flavor. This can be done by icing most fish immediately after harvest, before rigor sets in. However, early icing can actually toughen some fish - sardine, mackerel, and warm-water fish such as tilapia - by disrupting their contraction control system. Fish are generally at their prime just when rigor has pa.s.sed, perhaps 8 to 24 hours after death, and begin to deteriorate soon after that.

Recognizing Fresh Fish Nowadays, consumers often have no idea where a given piece of fish in the market has come from, when and how it was harvested, how long it has been in transit, or how it has been handled. So it's important to be able to recognize good-quality fish when we see it. But looks and smell can be deceiving. Even perfectly fresh fish may not be of the best quality if it has been caught in a depleted state after sp.a.w.ning. So the ideal solution is to find a knowledgeable and reliable fish merchant who knows the seasonality of fish quality, and buys accordingly. Such a merchant is also more likely to be selective about his suppliers, and less likely to sell seafood that's past its prime.

It's preferable to have fillets and steaks cut to order from a whole fish, because cutting immediately exposes new surfaces to microbes and the air. Old cut surfaces will be stale and smelly.

Handling Freshly Killed FishSport fishermen may not get around to cooking their catch until it has already begun to stiffen. Fortunately, fish in rigor aren't as tough as beef or pork would be. It's a mistake, however, to cut up a freshly killed, pre-rigor fish into steaks or fillets, and not either cook or freeze the pieces immediately. If rigor develops in the pieces, the severed muscle fibers are free to contract, and they will shorten by as much as half into a corrugated, rubbery ma.s.s. If instead the pieces are quickly frozen, and then allowed to thaw gradually so that the muscle energy stores slowly run down while the piece shapes are maintained by some ice crystals, this contraction can be mostly avoided.

In the case of a whole fish: The skin should be glossy and taut. On less fresh fish it will be dull and wrinkled. Color is not a helpful guide because many skin colors fade quickly after the fish dies.

If present, the natural proteinaceous mucus covering the skin should be transparent and glossy. With time it dries out and dulls, the proteins coagulate to give a milky appearance, and the color goes from off-white to yellow to brown. The mucus is often washed off when the fish is cleaned.

The eyes should be bright, black, and convex. With time the transparent surface becomes opaque and gray and the orb flattens out.

The belly of an intact fish should not be swollen or soft or broken, all signs that digestive enzymes and bacteria have eaten through the gut into the abdominal cavity and muscle. In a dressed fish, all traces of the viscera should have been removed, including the long red kidney that runs along the backbone.

If the fish has already been cut up, then: The steaks and fillets should have a full, glossy appearance. With time, the surfaces dry out and the proteins coagulate into a dull film. There should be no brown edges, which are a sign of drying, oxidation of oils, and off-flavors.

Whether the fish is precut or whole, its odor should resemble fresh sea air or crushed green leaves, and be only slightly fishy. Strong fis.h.i.+ness comes from prolonged bacterial activity. More advanced age and spoilage are indicated by musty, stale, fruity, sulfurous, or rotten odors.

Storing Fresh Fish and Sh.e.l.lfish: Refrigeration and Freezing Once we've obtained good fish, the challenge is to keep it in good condition until we use it. The initial stages of inevitable deterioration are caused by fish enzymes and oxygen, which conspire to dull colors, turn flavor stale and flat, and soften the texture. They don't really make the fish inedible. That change is caused by microbes, especially bacteria, with which fish slime and gills come well stocked - particularly Pseudomonas Pseudomonas and its cold-tolerant ilk. They make fish inedible in a fraction of the time they take to spoil beef or pork, by consuming the savory free amino acids and then proteins and turning them into obnoxious nitrogen-containing substances (ammonia, trimethylamine, indole, skatole, putrescine, cadaverine) and sulfur compounds (hydrogen sulfide, skunky methanethiol). and its cold-tolerant ilk. They make fish inedible in a fraction of the time they take to spoil beef or pork, by consuming the savory free amino acids and then proteins and turning them into obnoxious nitrogen-containing substances (ammonia, trimethylamine, indole, skatole, putrescine, cadaverine) and sulfur compounds (hydrogen sulfide, skunky methanethiol).

The first defense against incipient spoilage is rinsing. Bacteria live and do their damage on the fish surface, and thorough was.h.i.+ng can remove most of them and their smelly by-products. Once the fish is washed and blotted dry, a close wrapping in wax paper or plastic film will limit exposure to oxygen.

Sh.e.l.lfish That Glow in the DarkSome ocean bacteria (species of Photobacterium Photobacterium and and Vibrio Vibrio) produce light by way of a particular chemical reaction that releases photons, and can cause shrimp and crab to glow in the dark! So far, these luminescent bacteria appear to be harmless to humans, though some can cause disease in the crustaceans. Their glow indicates that the crustaceans are laden with bacteria and thus not pristinely fresh.

But by far the most important defense against spoilage is temperature control. The colder the fish, the slower enzymes and bacteria do their damage.

Refrigeration: The Importance of Ice For most of the foods that we want to store fresh for a few days, the ordinary refrigerator is quite adequate. The exception to the rule is fresh fish, whose enzymes and microbes are accustomed to cold waters (p. 189). The key to maintaining the quality of fresh fish is ice. Fish lasts nearly twice as long in a 32F/0C slush as it does at typical refrigerator temperatures of 4045F/57C. It's desirable to keep fish on ice as continuously as possible: in the market display case, the shopping cart, the car, and in the refrigerator. Fine flake or chopped ice will make more even contact than larger cubes or slabs. Wrapping will prevent direct contact with water that leaches away flavor. For most of the foods that we want to store fresh for a few days, the ordinary refrigerator is quite adequate. The exception to the rule is fresh fish, whose enzymes and microbes are accustomed to cold waters (p. 189). The key to maintaining the quality of fresh fish is ice. Fish lasts nearly twice as long in a 32F/0C slush as it does at typical refrigerator temperatures of 4045F/57C. It's desirable to keep fish on ice as continuously as possible: in the market display case, the shopping cart, the car, and in the refrigerator. Fine flake or chopped ice will make more even contact than larger cubes or slabs. Wrapping will prevent direct contact with water that leaches away flavor.

In general, well iced fatty salt.w.a.ter fish - salmon, herring, mackerel, sardine - will remain edible for about a week, lean cold-water fish - cod, sole, tuna, trout - about two weeks, and lean warm-water fish - snappers, catfish, carp, tilapia, mullets - about three weeks. A large portion of these ice-lives may already have elapsed before the fish appear in the market.

Freezing To keep fish in edible condition for more than a few days, it's necessary to lower its temperature below the freezing point. This effectively stops spoilage by bacteria, but it doesn't stop chemical changes in the fish tissues that produce stale flavors. And the proteins in fish muscle (especially cod and its relatives) turn out to be unusually susceptible to "freeze denaturation," in which the loss of their normal environment of liquid water breaks some of the bonds holding the proteins in their intricately folded structure. The unfolded proteins are then free to bond to each other. The result is tough, spongy network that can't hold onto its moisture when it's cooked, and in the mouth becomes a dry, fibrous wad of protein. To keep fish in edible condition for more than a few days, it's necessary to lower its temperature below the freezing point. This effectively stops spoilage by bacteria, but it doesn't stop chemical changes in the fish tissues that produce stale flavors. And the proteins in fish muscle (especially cod and its relatives) turn out to be unusually susceptible to "freeze denaturation," in which the loss of their normal environment of liquid water breaks some of the bonds holding the proteins in their intricately folded structure. The unfolded proteins are then free to bond to each other. The result is tough, spongy network that can't hold onto its moisture when it's cooked, and in the mouth becomes a dry, fibrous wad of protein.

So once you've brought frozen fish home, it's best to use it as soon as possible. In general, the storage life of fish in ordinary freezers, wrapped tightly and/or glazed with water to prevent freezer burn (freeze the fish, then dip in water, refreeze, and repeat to build up a protective ice layer) is about four months for fatty fish such as salmon, six months for most lean white fish and shrimp. Like frozen meats, frozen fish should be thawed in the refrigerator or in a bath of ice water (p. 147).

Irradiation Irradiation preserves food by way of high-energy particles that damage the DNA and proteins of spoilage microbes (p. 782). Pilot studies have found that irradiation can extend the refrigerated shelf life of fresh fish by as much as two weeks. However, the initial deterioration of fish quality is caused by the action of fish enzymes and oxygen, and this action proceeds despite irradiation. Also, irradiation can produce off-flavors of its own. It's unclear whether irradiation will become an important means of preservation for fish.

Unheated Preparations of Fish and Sh.e.l.lfish People in many parts of the world enjoy eating ocean fish and sh.e.l.lfish raw. Unlike meats, fish have the advantage of relatively tender muscle and a naturally savory taste, and are easier and more interesting to eat raw. They offer the experience of a kind of primal freshness. The cook may simply provide a few accompanying ingredients with complementary flavors and textures, or firm the fish's texture by means of light acidification (ceviche), salting (poke), or both (anchovies briefly cured in salt and lemon juice). And raw preparations don't require the use of fuel, which is often scarce on islands and coastlines.

All uncooked fresh fish pose the risk of carrying a number of microbes and parasites that can cause food poisoning or infection (p. 185). Only very fresh fish of the highest quality should be prepared for consumption raw, and they should be handled very carefully in the kitchen to avoid contamination by other foods. Because parasitic worms are often found in otherwise high-quality fish, the U.S. Food Code specifies that fish sold for raw consumption should be frozen throughout for a minimum of 15 hours at 31F/35C, or for seven days at 4F/20C. The exceptions to this rule are the tuna species commonly served in j.a.panese sus.h.i.+ and sas.h.i.+mi (bluefin, yellowfin, bigeye, albacore), which are rarely infected with parasites. Despite this exception, most tuna are blast-frozen at sea so that the boats can stay out for several days at a time. Sus.h.i.+ connoisseurs say that the texture of properly frozen tuna is acceptable, but that the flavor suffers.

Sus.h.i.+ and Sas.h.i.+mi Probably the commonest form of raw fish is sus.h.i.+, whose popularity spread remarkably in the late 20th century from its home in j.a.pan. The original sus.h.i.+ seems to have been the fermented preparation narezus.h.i.+ narezus.h.i.+ (p. 235); (p. 235); sus.h.i.+ sus.h.i.+ means "salted" and now applies more to the flavored rice, not the fish. The familiar bite-sized morsels of raw fish and lightly salted and acidified rice are means "salted" and now applies more to the flavored rice, not the fish. The familiar bite-sized morsels of raw fish and lightly salted and acidified rice are nigiri nigiri sus.h.i.+, meaning "grasped" or "squeezed," since the rice portion is usually molded by hand. The ma.s.s-produced version of sus.h.i.+ found in supermarkets is formed by industrial robots. sus.h.i.+, meaning "grasped" or "squeezed," since the rice portion is usually molded by hand. The ma.s.s-produced version of sus.h.i.+ found in supermarkets is formed by industrial robots.

Sus.h.i.+ chefs take great care to avoid contamination of the fish. They use a solution of cold water and chlorine bleach to clean surfaces between preparations, and they change cleaning solutions and cloths frequently during service.

Tart Ceviche and Kinilaw Ceviche is an ancient dish from the northern coast of South America, in which small cubes or thin slices of raw fish are "cooked" by immersing them in citrus juice or another acidic liquid, usually with onion, chilli peppers, and other seasonings. This period of marination changes both the appearance and texture of the fish: in a thin surface layer if it lasts 1545 minutes, throughout if it lasts a few hours. The high acidity denatures and coagulates the proteins in the muscle tissue, so that the gel-like translucent tissue becomes opaque and firm: but more delicately than it does when heated, and with none of the flavor changes caused by high temperatures. is an ancient dish from the northern coast of South America, in which small cubes or thin slices of raw fish are "cooked" by immersing them in citrus juice or another acidic liquid, usually with onion, chilli peppers, and other seasonings. This period of marination changes both the appearance and texture of the fish: in a thin surface layer if it lasts 1545 minutes, throughout if it lasts a few hours. The high acidity denatures and coagulates the proteins in the muscle tissue, so that the gel-like translucent tissue becomes opaque and firm: but more delicately than it does when heated, and with none of the flavor changes caused by high temperatures.

Kinilaw is the indigenous Philippine version of acid marination. Morsels of fish or sh.e.l.lfish are dipped for only a few seconds into an acidic liquid, often vinegar made from the coconut, nipa palm, or sugarcane, to which condiments have been added. In the case of "jumping salad," tiny shrimp or crabs are sprinkled with salt, doused with lime juice, and eaten alive and moving. is the indigenous Philippine version of acid marination. Morsels of fish or sh.e.l.lfish are dipped for only a few seconds into an acidic liquid, often vinegar made from the coconut, nipa palm, or sugarcane, to which condiments have been added. In the case of "jumping salad," tiny shrimp or crabs are sprinkled with salt, doused with lime juice, and eaten alive and moving.

Salty Poke and Lomi To the world's repertoire of raw fish dishes, the Hawaiian islands have contributed poke poke ("slice," "cut") and ("slice," "cut") and lomi lomi ("rub," "press," "squeeze"). These are small pieces of tuna, marlin, and other fish, coated with salt for varying periods (until the fish stiffens, if it's to be kept for some time), and mixed with other flavorful ingredients, traditionally seaweed and roasted candlenuts. Lomi is unusual in that the piece of fish is first worked between the thumb and fingers before salting, to break some of the muscle sheets and fibers apart from each other and soften the texture. ("rub," "press," "squeeze"). These are small pieces of tuna, marlin, and other fish, coated with salt for varying periods (until the fish stiffens, if it's to be kept for some time), and mixed with other flavorful ingredients, traditionally seaweed and roasted candlenuts. Lomi is unusual in that the piece of fish is first worked between the thumb and fingers before salting, to break some of the muscle sheets and fibers apart from each other and soften the texture.

Cooking Fish and Sh.e.l.lfish The muscle tissues of fish and sh.e.l.lfish react to heat much as beef and pork do, becoming opaque, firm, and more flavorful. However, fish and sh.e.l.lfish are distinctive in a few important ways, above all in the delicacy and activity of their proteins. They therefore pose some special challenges to the cook who wants to obtain a tender, succulent texture. Sh.e.l.lfish in turn have some special qualities of their own; they're described beginning on p. 218.

If it's more important to produce the safest possible dish than the most delicious one, then the task is simpler: cook all fish and sh.e.l.lfish to an internal temperature between 185F/83C and the boil. This will kill both bacteria and viruses.

How Heat Transforms Raw Fish Heat and Fish Flavor The mild flavor of raw fish gets stronger and more complex as its temperature rises during cooking. At first, moderate heat speeds the activity of muscle enzymes, which generate more amino acids and reinforce the sweet-savory taste, and the volatile aroma compounds already present become more volatile and more noticeable. As the fish cooks through, its taste becomes somewhat muted as amino acids and IMP combine with other molecules, while the aroma grows yet stronger and more complex as fatty-acid fragments, oxygen, amino acids, and other substances react with each other to produce a host of new volatile molecules. If the surface temperature exceeds the boiling point, as it does during grilling and frying, the Maillard reactions produce typical roasted, browned aromas (p. 778). The mild flavor of raw fish gets stronger and more complex as its temperature rises during cooking. At first, moderate heat speeds the activity of muscle enzymes, which generate more amino acids and reinforce the sweet-savory taste, and the volatile aroma compounds already present become more volatile and more noticeable. As the fish cooks through, its taste becomes somewhat muted as amino acids and IMP combine with other molecules, while the aroma grows yet stronger and more complex as fatty-acid fragments, oxygen, amino acids, and other substances react with each other to produce a host of new volatile molecules. If the surface temperature exceeds the boiling point, as it does during grilling and frying, the Maillard reactions produce typical roasted, browned aromas (p. 778).

Sh.e.l.lfish have their own distinctive cooked flavors (pp. 221, 225). Cooked fish fall into four broad flavor families.

Salt.w.a.ter white fish are the mildest.

Freshwater white fish have a stronger aroma thanks to their larger repertoire of fatty-acid fragments and traces of earthiness from ponds and tanks. Freshwater trout have characteristic sweet and mushroomy aromas.

Salmon and sea-run trout, thanks to the carotenoid pigments that they acc.u.mulate from ocean crustaceans, develop fruity, flowery aromas and a distinctive family note (from an oxygen-containing carbon ring).

Tuna, mackerel, and their relatives have a meaty, beefy aroma.

Fis.h.i.+ness and How to Fight It The house-permeating "fishy" aroma of cooked fish appears to involve a group of volatile molecules formed by fatty-acid fragments reacting with TMAO (p. 193). j.a.panese scientists have found that certain ingredients help reduce the odor, apparently by limiting fatty-acid oxidation or preemptively reacting with TMAO: these include green tea and such aromatics as onion, bay, sage, clove, ginger, and cinnamon, which may also mask the fishy smell with their own. Acidity - whether in a poaching liquid, or in a b.u.t.termilk dip before frying - also mutes the volatility of fishy amines and aldehydes, and helps break down muddy-smelling geosmin that farmed freshwater fish (catfish, carp) sometimes acc.u.mulate from blue-green algae. The house-permeating "fishy" aroma of cooked fish appears to involve a group of volatile molecules formed by fatty-acid fragments reacting with TMAO (p. 193). j.a.panese scientists have found that certain ingredients help reduce the odor, apparently by limiting fatty-acid oxidation or preemptively reacting with TMAO: these include green tea and such aromatics as onion, bay, sage, clove, ginger, and cinnamon, which may also mask the fishy smell with their own. Acidity - whether in a poaching liquid, or in a b.u.t.termilk dip before frying - also mutes the volatility of fishy amines and aldehydes, and helps break down muddy-smelling geosmin that farmed freshwater fish (catfish, carp) sometimes acc.u.mulate from blue-green algae.

Preparing Fish in Ancient RomeIn summer in their lower rooms they often had clear fresh water run in open channels underneath, in which there were a lot of live fish, which the guests would select and catch in their hands to be prepared to the taste of each. Fish has always had this privilege, as it still does, that the great have pretensions of knowing how to prepare it. Indeed its taste is much more exquisite than that of flesh, at least to me.- Michel de Montaigne, "Of Ancient Customs," ca. 1580 Simple physical treatments can also minimize fishy odors. Start with very fresh fish and wash it well to remove oxidized fats and bacteria-generated amines from the surface. Enclose the fish in a covered pan, or pastry crust, or parchment or foil envelope, or poaching liquid, to reduce the exposure of its surface to the air; frying, broiling, and baking all propel fishy vapors into the kitchen. And let the fish cool down to some extent before removing it from its enclosure; this will reduce the volatility of the vapors that do escape.

Heat and Fish Texture The real challenge in cooking both fish and meat is to get the texture right. And the key to fish and meat texture is the transformation of muscle proteins (p. 149). The cook's challenge is to control the process of coagulation so that it doesn't proceed too far, to the point that the muscle fibers become hard and the juice flow dries up completely. The real challenge in cooking both fish and meat is to get the texture right. And the key to fish and meat texture is the transformation of muscle proteins (p. 149). The cook's challenge is to control the process of coagulation so that it doesn't proceed too far, to the point that the muscle fibers become hard and the juice flow dries up completely.

Target Temperatures In meat cooking, the critical temperature is 140F/60C, when the connective-tissue collagen sheath around each muscle cell collapses, shrinks, and puts the squeeze on the fluid-filled insides, forcing juice out of the meat. But fish collagen doesn't play the same critical role, because its squeezing power is relatively weak and it collapses before coagulation and fluid flow are well underway. Instead, it's mainly the fiber protein myosin and its coagulation that determine fish texture. Fish myosin and its fellow fiber proteins are more sensitive to heat than their land-animal counterparts. Where meats begin to shrink from coagulation and major fluid loss at 140F/60C and are dry by 160F/70C, most fish shrink at 120F/50C and begin to become dry around 140F/60C. (Compare the behaviors of meat and fish proteins in the boxes on pp. 152 and 210). In meat cooking, the critical temperature is 140F/60C, when the connective-tissue collagen sheath around each muscle cell collapses, shrinks, and puts the squeeze on the fluid-filled insides, forcing juice out of the meat. But fish collagen doesn't play the same critical role, because its squeezing power is relatively weak and it collapses before coagulation and fluid flow are well underway. Instead, it's mainly the fiber protein myosin and its coagulation that determine fish texture. Fish myosin and its fellow fiber proteins are more sensitive to heat than their land-animal counterparts. Where meats begin to shrink from coagulation and major fluid loss at 140F/60C and are dry by 160F/70C, most fish shrink at 120F/50C and begin to become dry around 140F/60C. (Compare the behaviors of meat and fish proteins in the boxes on pp. 152 and 210).

In general, fish and sh.e.l.lfish are firm but still moist when cooked to 130140F/5560C. Some dense-fleshed fish, including tuna and salmon, are especially succulent at 120F, when still slightly translucent and jelly-like. Creatures with a large proportion of connective-tissue collagen - notably the cartilagenous sharks and skates - benefit from higher temperatures and longer cooking to turn it into gelatin, and can be chewy unless cooked to 140F/60C or higher. Some molluscs are also rich in collagen and benefit from long cooking (p. 225).

Why Some Fish Seem to Dry Out Faster Than OthersOne puzzling aspect of fish cooking is the fact that different fish can have surprisingly different tolerances for overcooking, despite similar protein and fat contents. Rockfish, snappers, and mahimahi, for example, seem more moist and forgiving than tuna or swordfish, which tend to become firm and dry very quickly. j.a.panese researchers have peered through the microscope and identified the likely culprits: the enzymes and other proteins in muscle cells that are not locked in the contracting fibrils, but float free in the cell to perform other functions. These proteins generally coagulate at a higher temperature than the main contractile protein myosin. So when myosin coagulates and squeezes cell fluids out, these other proteins flow out with the fluid. Some of them then coagulate in the s.p.a.ces between the muscle cells, where they glue the cells together and prevent them from sliding easily apart when we chew. Highly active swimmers like tunas and billfish require more enzymes than sedentary bottom fish like snappers and cod, so their fibers get glued more firmly to each other if they are cooked to 130F/55C and above.

The Effects of Heat on Fish Proteins and Texture Gentle Heat and Close Attention In practice, it's all too easy to overshoot the ideal temperature range for fish. It takes only a matter of seconds to overcook a thin fillet. Two characteristics of fish add to the trickiness of cooking them well. First, whole fish and fillets are thick at the center and taper down to nothing at the edges: so thin areas overcook while the thick areas cook through. And second, fish vary widely in their chemical and physical condition, and therefore in their response to heat. The fillets of cod, bluefish, and other species often suffer from some degree of gaping, separations of muscle layers through which heat penetrates more rapidly. Such fish as tuna, swordfish, and shark have very dense flesh, crammed full of protein (around 25%), which absorbs a lot of heat before its temperature rises; less active members of the cod family get by with less protein (1516%) in their muscle, and cook more rapidly. Fat transfers heat more slowly than protein, so fatty fish take longer to cook than lean fish of the same size. And the very same species of fish can be protein- or fat-rich one month, depleted and quickly heated the next. In practice, it's all too easy to overshoot the ideal temperature range for fish. It takes only a matter of seconds to overcook a thin fillet. Two characteristics of fish add to the trickiness of cooking them well. First, whole fish and fillets are thick at the center and taper down to nothing at the edges: so thin areas overcook while the thick areas cook through. And second, fish vary widely in their chemical and physical condition, and therefore in their response to heat. The fillets of cod, bluefish, and other species often suffer from some degree of gaping, separations of muscle layers through which heat penetrates more rapidly. Such fish as tuna, swordfish, and shark have very dense flesh, crammed full of protein (around 25%), which absorbs a lot of heat before its temperature rises; less active members of the cod family get by with less protein (1516%) in their muscle, and cook more rapidly. Fat transfers heat more slowly than protein, so fatty fish take longer to cook than lean fish of the same size. And the very same species of fish can be protein- or fat-rich one month, depleted and quickly heated the next.

There are several ways to work around these inherent obstacles and uncertainties: Cook the fish through with the gentlest possible heat, so that the outer portions aren't badly overcooked. Oven baking and poaching well below the boil are two good ways to do this, after an initial and brief high-temperature treatment to brown and/or sterilize the surfaces.

Compensate for uneven thickness by cutting slashes in the thick areas every 12 cm. This effectively divides the thick areas into smaller portions and allows heat to penetrate more rapidly. Another strategy for relatively large portions is to cover thin areas loosely with aluminum foil, which blocks radiant heat and slows their cooking.

Check the fish early and often for doneness. Simple formulas - 10 minutes to the inch is a popular one - and past experience can get you in the vicinity of the correct time, but there's no subst.i.tute for checking the particular piece. This can be done by measuring the internal temperature with a reliable thermometer, peering into a small incision to see whether the interior is still translucent or already opaque, pulling on a small bone to see whether the connective tissue has dissolved enough to release it, or pus.h.i.+ng a small skewer or toothpick into the flesh to see whether it encounters resistance from coagulated muscle fibers.

Why Careful Cooking Sometimes Makes Fish Mushy Slow and gentle heating has an important place in meat cooking, and some fish - Atlantic salmon, for example - can develop an almost custard-like texture if heated gently to 120F /50C. In fish cooking, however, slow cooking can sometimes produce an unpleasant, mushy texture. This is caused by protein-digesting enzymes in the muscle cells of active fish and sh.e.l.lfish that help convert muscle ma.s.s into energy (p. 189). Some of these enzymes become increasingly active as the temperature rises during cooking, until they're inactivated at 130140F/5560C. Mush-p.r.o.ne fish (see box, p. 212) are best either cooked quickly to an enzyme-killing but somewhat drying 160F/70C, or else cooked to a lower temperature and served immediately. Slow and gentle heating has an important place in meat cooking, and some fish - Atlantic salmon, for example - can develop an almost custard-like texture if heated gently to 120F /50C. In fish cooking, however, slow cooking can sometimes produce an unpleasant, mushy texture. This is caused by protein-digesting enzymes in the muscle cells of active fish and sh.e.l.lfish that help convert muscle ma.s.s into energy (p. 189). Some of these enzymes become increasingly active as the temperature rises during cooking, until they're inactivated at 130140F/5560C. Mush-p.r.o.ne fish (see box, p. 212) are best either cooked quickly to an enzyme-killing but somewhat drying 160F/70C, or else cooked to a lower temperature and served immediately.

Preparations for Cooking Cleaning and Cutting Most fish in U.S. markets are sold precleaned and precut. This is certainly convenient, but it also means that the scaled and cut surfaces have been exposed to the air and bacteria for hours or days, drying out and developing off-flavors. Preparing fish at the last minute can give fresher results. Both whole fish and pieces should be rinsed thoroughly in cold water to remove fragments of inner organs, the acc.u.mulation of odorous TMA, other bacterial by-products, and bacteria themselves. Most fish in U.S. markets are sold precleaned and precut. This is certainly convenient, but it also means that the scaled and cut surfaces have been exposed to the air and bacteria for hours or days, drying out and developing off-flavors. Preparing fish at the last minute can give fresher results. Both whole fish and pieces should be rinsed thoroughly in cold water to remove fragments of inner organs, the acc.u.mulation of odorous TMA, other bacterial by-products, and bacteria themselves.

Presalting j.a.panese cooks briefly presalt most fish and shrimp to remove surface moisture and odor and firm the outer layers. This is especially useful for getting fish skin to crisp and brown quickly when fried. As is true for meats, presoaking fish and sh.e.l.lfish in a 35% salt brine will cause the flesh to absorb both water and salt, with moisturizing and tenderizing results (p. 155). j.a.panese cooks briefly presalt most fish and shrimp to remove surface moisture and odor and firm the outer layers. This is especially useful for getting fish skin to crisp and brown quickly when fried. As is true for meats, presoaking fish and sh.e.l.lfish in a 35% salt brine will cause the flesh to absorb both water and salt, with moisturizing and tenderizing results (p. 155).

Techniques for Cooking Fish and Sh.e.l.lfish The many methods for heating meats and fish are described in detail in the previous chapter, pp. 15665. Briefly, "dry" heating methods - grilling, frying, baking - produce surface temperatures high enough to produce the colors and flavors of the browning reactions, while "moist" techniques - steaming, poaching - fail to trigger browning, but heat foods more rapidly and can supply flavors from other ingredients. (Chinese cooks often get the best of both methods by first frying a fish and then finis.h.i.+ng it with a brief braise in a flavorful sauce.) Fish don't require long cooking to dissolve their connective tissue and become tender. The purpose of any given technique is to get the center of the fish promptly to the proper temperature without overcooking the outer portions.

Handling Delicate Flesh Its delicate and spa.r.s.e connective tissue means that most cooked fish is troublesomely fragile to work with. It's best to manipulate fish as little as possible during and after cooking, and to support the whole piece when moving it, small ones with a spatula, large ones on a rack or a stretcher of foil or cheesecloth. Neat individual portions should be cut before cooking, when the tissue is still cohesive; after cooking, even a sharp knife pulls flakes and shreds from the weakened matrix. Its delicate and spa.r.s.e connective tissue means that most cooked fish is troublesomely fragile to work with. It's best to manipulate fish as little as possible during and after cooking, and to support the whole piece when moving it, small ones with a spatula, large ones on a rack or a stretcher of foil or cheesecloth. Neat individual portions should be cut before cooking, when the tissue is still cohesive; after cooking, even a sharp knife pulls flakes and shreds from the weakened matrix.

Grilling and Broiling Grilling and broiling are high-temperature techniques that cook mainly by radiant heat, and are well suited to relatively thin whole fish, fillets, and steaks. For successful results, the thickness of the fish and the distance from the heat must be balanced so that the fish can be cooked through at the center without the outer portions becoming badly overcooked and dry. The fish must either be firm enough to hold together when turned with a spatula - tuna, swordfish, and halibut do well - or be supported in a closed wire rack that can be turned without disturbing the fish. Thin fillets of sole and other flatfish are sometimes put on a preheated b.u.t.tered plate or aromatic cedar board and broiled without turning. Grilling and broiling are high-temperature techniques that cook mainly by radiant heat, and are well suited to relatively thin whole fish, fillets, and steaks. For successful results, the thickness of the fish and the distance from the heat must be balanced so that the fish can be cooked through at the center without the outer portions becoming badly overcooked and dry. The fish must either be firm enough to hold together when turned with a spatula - tuna, swordfish, and halibut do well - or be supported in a closed wire rack that can be turned without disturbing the fish. Thin fillets of sole and other flatfish are sometimes put on a preheated b.u.t.tered plate or aromatic cedar board and broiled without turning.

Mush-p.r.o.ne Fish and Sh.e.l.lfishj.a.panese studies have found that the following fish and sh.e.l.lfish have especially active protein-digesting enzymes in their muscle, and tend to become mushy when cooked slowly or held at temperatures around 130140F/5560C.

1. Sardine 2. Herring 3. Mackerel 4. Tunas 5. Chum salmon 6. Whiting 7. Pollack 8. Tilapia 9. Shrimp 10. Lobster Baking Oven baking is a versatile method for cooking fish. Because it transfers heat to the fish mainly by hot air, which is an inefficient method (p. 784), it's relatively slow and gentle, and makes it easier to avoid overcooking. This is true as long as the container remains open to the oven air, when the fish moisture evaporates and cools the surface to well below the thermostat temperature. If the container is closed, water vapor builds up inside and the fish quickly steams rather than bakes. The dry oven air is also useful for concentrating the fish juices and any moist flavoring ingredients - wine, or a bed of aromatic vegetables, for example - and it can also trigger aroma-producing browning reactions. Oven baking is a versatile method for cooking fish. Because it transfers heat to the fish mainly by hot air, which is an inefficient method (p. 784), it's relatively slow and gentle, and makes it easier to avoid overcooking. This is true as long as the container remains open to the oven air, when the fish moisture evaporates and cools the surface to well below the thermostat temperature. If the container is closed, water vapor builds up inside and the fish quickly steams rather than bakes. The dry oven air is also useful for concentrating the fish juices and any moist flavoring ingredients - wine, or a bed of aromatic vegetables, for example - and it can also trigger aroma-producing browning reactions.

Low-Temperature Baking In one extreme version of baking, the oven is set for temperatures as low as 200 or 225F/ 95110C, and the cooking is gentle indeed. Because the fish surface is simultaneously warmed by the oven air and cooled by evaporation of its moisture, the actual maximum temperature of the fish surface in such an oven may be just 120130F, the internal temperature even lower, and the fish ends up with a barely cooked, almost custard-like texture. The appearance of fish cooked this way is often marred by the off-white globs of solidified cell fluid, which is able to leak out of the tissue before it gets hot enough for its dissolved proteins to coagulate (normally these proteins, which const.i.tute as much as 25% of the total, coagulate within the muscle). In one extreme version of baking, the oven is set for temperatures as low as 200 or 225F/ 95110C, and the cooking is gentle indeed. Because the fish surface is simultaneously warmed by the oven air and cooled by evaporation of its moisture, the actual maximum temperature of the fish surface in such an oven may be just 120130F, the internal temperature even lower, and the fish ends up with a barely cooked, almost custard-like texture. The appearance of fish cooked this way is often marred by the off-white globs of solidified cell fluid, which is able to leak out of the tissue before it gets hot enough for its dissolved proteins to coagulate (normally these proteins, which const.i.tute as much as 25% of the total, coagulate within the muscle).

High-Temperature Baking At the other extreme, a very hot oven is often used in restaurant kitchens to finish cooking through a portion of fish whose skin side has been browned in a hot frying pan; pan and fish together are then slipped into the oven, and the fish cooks through in a few minutes with heat from all directions, without the necessity of turning it. A 500F/260C oven can also be used to "oven fry" pieces of fish that have been breaded, spread out on a baking sheet, and moistened with oil. At the other extreme, a very hot oven is often used in restaurant kitchens to finish cooking through a portion of fish whose skin side has been browned in a hot frying pan; pan and fish together are then slipped into the oven, and the fish cooks through in a few minutes with heat from all directions, without the necessity of turning it. A 500F/260C oven can also be used to "oven fry" pieces of fish that have been breaded, spread out on a baking sheet, and moistened with oil.

Cooking Under Wraps: Crusts, Envelopes, and Others An ancient way of cooking fish is to enclose it in a layer of some material - clay, coa.r.s.e salt, leaves - to s.h.i.+eld it from direct heat, and then cook the whole package (see box below). The fish inside will be more evenly and gently cooked, though checking the temperature is still essential to avoid overcooking. Showy preparations with an edible crust of pastry or brioche (French An ancient way of cooking fish is to enclose it in a layer of some material - clay, coa.r.s.e salt, leaves - to s.h.i.+eld it from direct heat, and then cook the whole package (see box below). The fish inside will be more evenly and gently cooked, though checking the temperature is still essential to avoid overcooking. Showy preparations with an edible crust of pastry or brioche (French en croute en croute) are baked in the oven. A more versatile technique is the use of a thin envelope of parchment (en papillote), or aluminum foil, or a leaf, either neutral (lettuce) or flavorful (cabbage, fig, banana, lotus, hoja santa hoja santa), which can be used with almost any heat source, from grill to steamer. But once the contents get hot enough, nearly all the heating is done by the juices of the fish and vegetables themselves, which surround the food and steam it. The envelope can be served intact and opened by the diner, releasing aromas that would otherwise have been left behind in the kitchen.

Roman Fish in ParchmentStuffed BonitoBone the bonito. Pound together pennyroyal, c.u.min, pepper, mint, nuts, and honey. Stuff the fish with this mixture and sew it up. Wrap the fish in paper and place it in a covered pan over steam. Season with oil, reduced wine, and fermented fish paste.- Apicius, first few centuries CE CE Frying Fish is fried in hot metal pans in two different ways: with just enough oil to lubricate the fish surface in contact with the pan, or with enough oil to surround and cover most or all of the fish. Either way, the fish is exposed to temperatures sufficient to dry out and brown its surfaces, and therefore develops a contrastingly crisp outside and characteristic, rich aroma. Because high heat also makes the lean flesh fibrous and chewy, fish to be fried is often given a protective coating of starchy and/or proteinaceous material, so that the coating can crisp while the fish remains moist. Common coatings include flour and flour-based batters; cornmeal or breadcrumbs; ground spices or nuts or shredded coconut; thin shreds, strings, or sheets of potato or another starchy root (sometimes cut and arranged to look like fish scales); and rice paper. The adhesion of coating to fish can be improved by first lightly salting the fish, which draws some protein-rich, sticky fluid to the surface. Fish is fried in hot metal pans in two different ways: with just enough oil to lubricate the fish surface in contact with the pan, or with enough oil to surround and cover most or all of the fish. Either way, the fish is exposed to temperatures sufficient to dry out and brown its surfaces, and therefore develops a contrastingly crisp outside and characteristic, rich aroma. Because high heat also makes the lean flesh fibrous and chewy, fish to be fried is often given a protective coating of starchy and/or proteinaceous material, so that the coating can crisp while the fish remains moist. Common coatings include flour and flour-based batters; cornmeal or breadcrumbs; ground spices or nuts or shredded coconut; thin shreds, strings, or sheets of potato or another starchy root (sometimes cut and arranged to look like fish scales); and rice paper. The adhesion of coating to fish can be improved by first lightly salting the fish, which draws some protein-rich, sticky fluid to the surface.

Frying is also an excellent way to crisp the skin on a whole fish or fillet. The skin will dry out more rapidly and thoroughly if it's first salted to remove moisture.

Fried surfaces stay crispest when they're exposed to the air; confined between the moist fish and plate, a crisp skin or coating soon reabsorbs moisture and softens. Serve crunchy-skinned fillets skin-side up, or at least give the skin room to breathe.

Sauteing When frying in a small amount of oil, it's best to heat the pan before adding the oil (this reduces oil breakdown into sticky polymers), or lightly oil the fish surfaces instead. If an especially crisp skin or crust is desired, the fish should be started on that side, pressed gently to maximize contact between hot pan and skin, and left long enough on high heat to develop the desired texture, then turned once and allowed to finish cooking through on lower heat. Thin fillets cook in just a few minutes per side, and require a hotter pan in order to brown quickly. When frying in a small amount of oil, it's best to heat the pan before adding the oil (this reduces oil breakdown into sticky polymers), or lightly oil the fish surfaces instead. If an especially crisp skin or crust is desired, the fish should be started on that side, pressed gently to maximize contact between hot pan and skin, and left long enough on high heat to develop the desired texture, then turned once and allowed to finish cooking through on lower heat. Thin fillets cook in just a few minutes per side, and require a hotter pan in order to brown quickly.

Deep Frying In deep frying, the fish is usually protected with a batter or breading, and more or less immersed in oil, a relatively inefficient conductor of heat, at a temperature around 350F/175C, well above the boiling point of water. The surface dries out and gets hot enough to brown and to develop a characteristic rich aroma and a crisp crust that acts as a layer of insulation and slows subsequent heating. The fish is therefore heated evenly from all directions, but fairly gently, giving the cook some leeway in removing it while it's still moist inside. In deep frying, the fish is usually protected with a batter or breading, and more or less immersed in oil, a relatively inefficient conductor of heat, at a temperature around 350F/175C, well above the boiling point of water. The surface dries out and gets hot enough to brown and to develop a characteristic rich aroma and a crisp crust that acts as a layer of insulation and slows subsequent heating. The fish is therefore heated evenly from all directions, but fairly gently, giving the cook some leeway in removing it while it's still moist inside.

j.a.panese Tempura The cla.s.sic j.a.panese version of fried fish is fish The cla.s.sic j.a.panese version of fried fish is fish tempura, tempura, a preparation and term that were borrowed in the late 16th century from Portuguese and Spanish missionaries who cooked fish during fasting seasons ( a preparation and term that were borrowed in the late 16th century from Portuguese and Spanish missionaries who cooked fish during fasting seasons (tempora means "period of time"). Tempura - which now means a batter-fried food of any sort - is characterized by relatively small pieces that cook in just a few minutes, and a fresh, barely mixed batter made from an egg yolk, 1 cup/120 gm flour, and 1 cup/250 ml ice water stirred together with chopsticks just before the frying. As in all batters, cold water makes the mixture more viscous and thus better retained on the fish surface. The freshness of the batter means that the flour particles have little time to soak up water, so the moisture is rapidly removed from their surfaces during frying to produce a crisp crust. And the minimal mixing means an uneven batter consistency and therefore an uneven, lacy coating on the fish, rather than a monolithic sheet. means "period of time"). Tempura - which now means a batter-fried food of any sort - is characterized by relatively small pieces that cook in just a few minutes, and a fresh, barely mixed batter made from an egg yolk, 1 cup/120 gm flour, and 1 cup/250 ml ice water stirred together with chopsticks just before the frying. As in all batters, cold water makes the mixture more viscous and thus better retained on the fish surface. The freshness of the batter means that the flour particles have little time to soak up water, so the moisture is rapidly removed from their surfaces during frying to produce a crisp crust. And the minimal mixing means an uneven batter consistency and therefore an uneven, lacy coating on the fish, rather than a monolithic sheet.

Simmering, Poaching, Stewing Immersing fish in hot liquid is a simple, flexible method that offers the cook unmatched control over the heating. The liquid can be very hot for cooking thin pieces in a matter of seconds, moderately hot for thicker pieces, or start out cold for gently cooking a whole fish through; it can be flavored in many different ways; and it can be turned into a sauce. When a fish or sh.e.l.lfish is served in a generous quant.i.ty of its cooking liquid, however supplemented with other ingredients, the French fittingly call it a preparation Immersing fish in hot liquid is a simple, flexible method that offers the cook unmatched control over the heating. The liquid can be very hot for cooking thin pieces in a matter of seconds, moderately hot for thicker pieces, or start out cold for gently cooking a whole fish through; it can be flavored in many different ways; and it can be turned into a sauce. When a fish or sh.e.l.lfish is served in a generous quant.i.ty of its cooking liquid, however supplemented with other ingredients, the French fittingly call it a preparation a la nage, a la nage, or "aswim." or "aswim."

The Cooking Liquids Because fish don't require prolonged cooking, there's little time for fish and cooking liquid to exchange flavors and mellow together. Cooking liquids for fish are therefore either fairly neutral and discarded - salted water, or a mixture of water and milk - or are prepared ahead of time to develop their flavor. In the French tradition, there are two cla.s.sic liquids for poaching fish: a tart, light infusion of vegetables and herbs, and a richer stock made from fish and vegetables. Because fish don't require prolonged cooking, there's little time for fish and cooking liquid to exchange flavors and mellow together. Cooking liquids for fish are therefore either fairly neutral and discarded - salted water, or a mixture of water and milk - or are prepared ahead of time to develop their flavor. In the French tradition, there are two cla.s.sic liquids for poaching fish: a tart, light infusion of vegetables and herbs, and a richer stock made from fish and vegetables.

Court bouillon, or "briefly boiled liquid," is a mixture of water, salt, wine or vinegar, and vegetable aromatics, cooked together for 3060 minutes into a medium that will lightly flavor the fish. The vegetables soften and release flavor more rapidly if the acid ingredient is added toward the end; black or white pepper is also added in the last 10 minutes to avoid overextraction of its bitter components. A whole fish poached in court bouillon will contribute both flavor and gelatin to the liquid, which can then be boiled down to a succulent sauce, or else kept as a fish stock and used later. or "briefly boiled liquid," is a mixture of water, salt, wine or vinegar, and vegetable aromatics, cooked together for 3060 minutes into a medium that will lightly flavor the fish. The vegetables soften and release flavor more rapidly if the acid ingredient is added toward the end; black or white pepper is also added in the last 10 minutes to avoid overextraction of its bitter components. A whole fish poached in court bouillon will contribute both flavor and gelatin to the liquid, which can then be boiled down to a succulent sauce, or else kept as a fish stock and used later.

Fish stocks, or fumets fumets (from the French for "aroma"), are also generally prepared in an hour or less, since longer simmering of fragile fish bones can dissolve calcium salts that then cloud the liquid and give it a chalky taste. Stocks are made with fish bones, skins, tr.i.m.m.i.n.gs, and heads, which are an especially rich source of gelatin and flavor. (Gills are omitted because their flavor deteriorates quickly.) The higher the proportion of fish, the more flavorful the stock; equal weights of water and fish work well (e.g. 2 lb/1 kg per quart/liter). The pot is left uncovered to prevent accidental boiling and clouding, and to allow slow evaporation and concentration. To make a clear consomme, the resulting strained stock can be clarified with a whipped mixture of egg whites and pureed raw fish, whose ma.s.sed proteins trap the tiny protein particles that cloud the liquid (p. 601) into a solid, easily removed ma.s.s. (from the French for "aroma"), are also generally prepared in an hour or less, since longer simmering of fragile fish bones can dissolve calcium salts that then cloud the liquid and give it a chalky taste. Stocks are made with fish bones, skins, tr.i.m.m.i.n.gs, and heads, which are an especially rich source of gelatin and flavor. (Gills are omitted because their flavor deteriorates quickly.) The higher the proportion of fish, the more flavorful the stock; equal weights of water and fish work well (e.g. 2 lb/1 kg per quart/liter). The pot is left uncovered to prevent accidental boiling and clouding, and to allow slow evaporation and concentration. To make a clear consomme, the resulting strained stock can be clarified with a whipped mixture of egg whites and pureed raw fish, whose ma.s.sed proteins trap the tiny protein particles that cloud the liquid (p. 601) into a solid, easily removed ma.s.s.

Fish are also poached in a variety of other liquids, including oil, b.u.t.ter, and such emulsions as beurre blanc and beurre monte (p. 632). These offer the advantage of slower, more gentle heat conduction and a more stable temperature thanks to reduced evaporative cooling.

Fish AspicsOrdinary fish consommes are seldom concentrated enough in gelatin to set into the firm, stable gel of an aspic (p. 607). For giving a glossy, aspic-like coating to a cold fish preparation, cooks may supplement their simple consomme with a small amount of commercial gelatin, or cook a second batch of fish in the consomme. Fish gelatin melts at a lower temperature than pig and beef gelatin - around 77F/25C, instead of 86F/30C - so a true fish aspic melts more readily in the mouth, seems more delicate, and releases its flavor faster.

Poaching Temperatures The great advantage of poaching fish is the ease of controlling the heat to obtain a moist, succulent result. Moderate-sized fillets and steaks should be started in liquid just below the boil and so hot enough to kill surface microbes instantly. The pot should then be taken off the heat, cool liquid added to bring its temperature down more quickly to around 150160F/6570C, and the fish cooked through gently. Allowing the cooked fish to cool while immersed in its liquid will leave it moister, since a hot piece of fish exposed to the air evaporates its surface moisture away. The great advantage of poaching fish is the ease of controlling the heat to obtain a moist, succulent result. Moderate-sized fillets and steaks should be started in liquid just below the boil and so hot enough to kill surface microbes instantly. The pot should then be taken off the heat, cool liquid added to bring its temperature down more quickly to around 150160F/6570C, and the fish cooked through gently. Allowing the cooked fish to cool while immersed in its liquid will leave it moister, since a hot piece of fish exposed to the air evaporates its surface moisture away.

Poaching at the Table Fish and sh.e.l.lfish cook so quickly in hot liquid that some cooks make poaching part of the presentation at the table. Pour steaming consomme into a bowl containing raw scallops or small cubes of fish, and the diner can witness their instant opacification and savor the evolution of their texture. Fish and sh.e.l.lfish cook so quickly in hot liquid that some cooks make poaching part of the presentation at the table. Pour steaming consomme into a bowl containing raw scallops or small cubes of fish, and the diner can witness their instant opacification and savor the evolution of their texture.

Soups and Stews; Bouillabaisse Fish stews and soups are dishes in which small pieces of fish, sometimes several different fish, are served in their cooking liquid, often with vegetables. The basic rules for simmering apply. The soup or stew base is prepared ahead of time, and the fish pieces added at the end and cooked just long enough to heat through: thick and dense pieces first, thin and delicate last. Combinations of fish and sh.e.l.lfish are a nice acknowledgment of the sea's bounteous variety. Fish stews and soups are dishes in which small pieces of fish, sometimes several different fish, are served in their cooking liquid, often with vegetables. The basic rules for simmering apply. The soup or stew base is prepared ahead of time, and the fish pieces added at the end and cooked just long enough to heat through: thick and dense pieces first, thin and delicate last. Combinations of fish and sh.e.l.lfish are a nice acknowledgment of the sea's bounteous variety.

A gentle simmer is usually preferred to a rolling boil so as to avoid breaking up delicate morsels. A partial exception to this rule is the bouillabaisse bouillabaisse of southern France, whose name includes the idea of boiling, and whose unique character depends on the vigorous agitation that boiling provides. A bouillabaisse starts with a stock made from sc.r.a.ps and small bony fish to provide gelatin and flavor, tomatoes and aromatics for flavor and color, and a large dollop of olive oil - perhaps a third of a cup/75 ml per quart/liter of liquid - which a fierce 10-minute boil emulsifies into fine droplets throughout the soup. The dissolved fish gelatin and suspended proteins coat the oil droplets and slow their coalescence (p. 628). The other pieces of fish are added last and simmered to cook through, and the soup is served immediately, before the oil has a chance to separate. of southern France, whose name includes the idea of boiling, and whose unique character depends on the vigorous agitation that boiling provides. A bouillabaisse starts with a stock made from sc.r.a.ps and small bony fish to provide gelatin and flavor, tomatoes and aromatics for flavor and color, and a large dollop of olive oil - perhaps a third of a cup/75 ml per quart/liter of liquid - which a fierce 10-minute boil emulsifies into fine droplets throughout the soup. The dissolved fish gelatin and suspended proteins coat the oil droplets and slow their coalescence (p. 628). The other pieces of fish are added last and simmered to cook through, and the soup is served immediately, before the oil has a chance to separate.

Steaming Steaming is a rapid way to cook fish and is especially appropriate for thin fillets, which can cook through quickly (thick pieces would overcook on the surface while their interior cooks through). Subtle aromas are contributed by herbs and spices, vegetables, and even seaweed, if they're included in the steaming water or provide a bed on which the fish sits. Steaming is a rapid way to cook fish and is especially appropriate for thin fillets, which can cook through quickly (thick pieces would overcook on the surface while their interior cooks through). Subtle aromas are contributed by herbs and spices, vegetables, and even seaweed, if they're included in the steaming water or provide a bed on which the fish sits.

Even cooking requires that the fish pieces be the same thickness, and that the steam have equal access to all surfaces. If fillets taper down to a very thin end, fold the thin layers over or interleave them with each other. More than one layer's worth of fish should be cooked in batches or divided among separate levels (as in stackable Chinese bamboo steamers). Relatively thick steaks or whole fish are best steamed below the boil, at an effective temperature of 180F/80C, to minimize overcooking of the surface. This can be achieved by lowering the heat on the pot and/or leaving the pot lid ajar. An even gentler effect is achieved by the Chinese method of steaming fish without a lid, in which steam and room air combine to give an effective cooking temperature of 150160F/6570C.

Microwaving Microwave versions of simmered or steamed fish can be quite successful thanks to the relatively thin dimensions of fillets and steaks, which the electromagnetic waves can penetrate fully and cook quickly. To prevent especially thin portions from overcooking, cover them with radiation-blocking pieces of aluminum foil (p. 787), or overlap them with each other to a consistent thickness. As in most microwave cooking, the food should be enclosed so that the surface doesn't dry out and toughen: wrap the fish pieces in parchment or the cooking dish with plastic wrap, or simply place the fish between two inverted plates. Waiting for the fish to cool down some before uncovering the dish will mean less likelihood of a steam burn, a smaller billow of fishy aromas into the air, and less moisture loss from the fish surface. Microwave versions of simmered or steamed fish can be quite successful thanks to the relatively thin dimensions of fillets and steaks, which the electromagnetic waves can penetrate fully and cook quickly. To prevent especially thin portions from overcooking, cover them with radiation-blocking pieces of aluminum foil (p. 787), or overlap them with each other to a consistent thickness. As in most microwave cooking, the food should be enclosed so that the surface doesn't dry out and toughen: wrap the fish pieces in parchment or the cooking dish with plastic wrap, or simply place the fish between two inverted plates. Waiting for the fish to cool down some before uncovering the dish will mean less likelihood of a steam burn, a smaller billow of fishy aromas into the air, and less moisture loss from the fish surface.

Stovetop Smoking Smoking whole fish is a time-consuming and elaborate process, and cold-smoking requires an appliance with separate chambers for the smoke source and the fish (p. 236). But it's a simple matter to flavor a few portions with smoke on the backyard grill, or even indoors. Line the interior of an ordinary saucepan and its lid with aluminum foil, scatter smokeable materials - small dry wood chips or sawdust, sugar, tea leaves, spices - on the bottom, place presalted fish pieces on a rack, turn the heat on high until smoke appears, then reduce the heat to medium, cover the pot tightly, and allow the fish to "bake" in this 400500F/ 200250C stovetop oven until barely cooked through. Smoking whole fish is a time-consuming and elaborate process, and cold-smoking requires an appliance with separate chambers for the smoke source and the fish (p. 236). But it's a simple matter to flavor a few portions with smoke on the backyard grill, or even indoors. Line the interior of an ordinary saucepan and its lid with aluminum foil, scatter smokeable materials - small dry wood chips or sawdust, sugar, tea leaves, spices - on the bottom, place presalted fish pieces on a rack, turn the heat on high until smoke appears, then reduce the heat to medium, cover the pot tightly, and allow the fish to "bake" in this 400500F/ 200250C stovetop oven until barely cooked through.

Fish Mixtures Like meats, fish can be chopped or pounded or ground up and mixed with other ingredients to make b.a.l.l.s, cakes, sa