Okay, so, I lied. As a diver and long-time dedicated fish nerd, I can assure you that fish--except in Dave Barry rants and Disney cartoons--do not have a secret language. They swim, eat, poop, and make more fish. They do not converse. What I'm really after here is the secret language of fish mongers and poissoniers, but that makes a less interesting title. So sue me.
I used to think I would be struck dumb if ever I saw a lucid explanation of how the flavors of various white fish meats compare. James Peterson, in the otherwise brilliant "Fish & Shellfish" describes most white-flesh fish as having a "delicate" flavor. What the hell is that supposed to mean? Am I supposed to think that red snapper, orange roughy, scrod, haddock, pacific halibut, and patagonian toughfish all taste exactly alike? Other, "fishier" tasting fish he describes as strong or moderately strong, which seems to reinforce this idea that all fish taste like degrees of the same thing.
Harold McGee's description (On Food and Cooking) of various fish flesh seems to bear this out. He describes the differences between freshwater and saltwater fish, the differences between dark and light fish meat, and the differences in a few special cases. That's about it. Generally, all white fish meats from the sea contain approximately the same set of chemical compounds. Some have a teeny bit more glutamine, making them richer. Some have more of an oceanic taste.
Is it not possible to differentiate these fish flavors beyond the simple question of how much fishiness they exude? Okay, in fairness to Peterson et al, there actually is a similarity in the flavor of many white-fleshed fish. Differentiating--on a verbal level--between perch, halibut, Patagonian toothfish, flounder, sole, cod, hake, and many others of those that Peterson labels "delicate" is a real bitch. The difference between flounder and cod, for example, is a distinction more of texture than of flavor.
I look back over that last sentence and think, "Well, that's a load of crap." Let's face it: you really can't segregate the chemical element of flavor from the tangible--not entirely. Texture is part of flavor. To that end, I can say that the cod and flounder differ in that the the flakes of cod are larger and have slightly more tooth than flounder. Many descriptions of the difference between various white-fleshed fish provide more detail on distinctions of texture and firmness than chemical differences in taste. This it true in part because the textural differences are easier to see and describe but also because they play a role in picking the proper fish for a particular preparation method. You would not, for example, grill dover sole. The sole would stick to the grill and disintegrate. Cod, on the other hand, can be cooked just about any way you like. Cod has a high enough fat content that you can do little to damage it. Cod, like most fish, dries as it cooks, and the flakes then tend to come apart more readily.
Considerations of delicacy and texture aside, though, is there any difference between various white fish of similar textures and sturdiness? Does it matter whether I use dover sole, lemon sole, gulf flounder, or turbot? They look approximately the same--the all have approximately the same chemical make-up. Don't they taste approximately the same?
And ,what the hell is fishiness, anyway? Anyone who has cooked even a few different types of fish has dealt at some point with this generally unpleasant and exasperatingly inconsistent feature. It's a nasty smell and taste that can have an ammonia component in muscular pelagic fish (tuna, mackerel, mahi-mahi) or elasmobranchs (sharks and rays).
Guarantees of fishiness: poor handling (dirt, water, hand oils), refreezing, too much time out of the freezer, slow freezing. Cooling can be a cause, too. I have found on various occasions that with salmon, mahi-mahi, halibut, and trout, leaving the dish to cool too long after cooking can result in the curse of fishiness. The same thing happens with squid.
The essential culprits in fishiness are amines. Ocean-going fish rely on amines to keep the salt out of their bodies. One of the predominant amines, glutamine, is responsible for the richer savory flavor of saltwater fish over freshwater fish. Snapper is rich in glutamine; walleye pike contains none. Unfortunately, the next most prominent amine, odorless trimethylamine oxide (TMAO) breaks down readily into the nasty, skunky trimethylamine (TMA) that causes the smell most people call fishy. Some fish, like mackerel and sardines, have enough enzymes in their tissue that the TMAO to TMA process begins as soon as air hits the flesh. Others like snapper and monkfish have far less enzymes in their flesh and tend to produce TMA far more slowly.
Sharks, rays, and a few random others like swordfish and mahi mahi rely on urea to control their salt content. Bacteria break down urea into ammonia almost as readily as TMAO becomes TMA.
Okay, but I'm heading off on a tangent. I didn't want to talk about fishy fish at the moment. I wanted to talk about white-meat fish that doesn't suffer much from the fishiness curse. I wanted to discuss four of my favorite fish: red snapper, monkfish, halibut, and mahi mahi. Of the four, halibut is the only truly white-flesh fish. Monkfish flesh has some pink streaks. Fresh red snapper flesh is actually a pale, crystalline pink. Mahi mahi flesh is off-white tending toward a dark rusty color. All four of these cook up (mostly) white. I have occasionally caught a whiff of fishiness from halibut, but generally these are forgiving meats in that you don't have to go out of your way to fight the fishiness (which you have to do in the case of, say, pompano, bonito, mackerel, sardines, and so on).
Friday, June 24, 2005
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