In fish cookery, shopping skills are more important than recipes and equipment. You can’t create a delicious fish dish from poor-quality fish. While it takes years to acquire a sushi chef’s mastery of fish buying, anyone with a keen interest in cooking can quickly become an expert fish shopper.
As a former commercial fisherman, I can tell you that freshness is only one aspect of good-quality fish. Flavorful, moist, succulent fish depends not only on how many days it’s out of the water, but also on how the fish was handled after the catch. A fish that goes through rigor mortis in ambient temperatures—on a riverbank or on the deck of a boat—will be soft in texture and bland in flavor. But when the fish is properly chilled, or even frozen, before the onset of rigor mortis, the flesh maintains its integrity. Therefore, the best-quality frozen fish can be virtually indistinguishable from the best fresh fish. In fact, much of the fish at sushi counters has been frozen using state-of-the-art techniques.
A great fish has a glistening, take-me-home-I’m-delicious look that catches your eye. The whole fish has all of its scales intact, a sign of proper handling. The eyes are clear and bright, and the gills, if still intact, are either bright red or pale—never brown or grayish. Good fish are firm and resilient to the touch and their smell is clean, fresh, almost sweet. Never buy a fish that smells like a fish. If possible, smell the gill and stomach cavity before buying; odors start there.
Once a fish is cut into fillets or steaks, quality is difficult to maintain because bacterial growth and moisture loss accelerate. A market that cuts its own fish is the best bet for finding good-quality fillets and steaks. As with whole fish, quality fillets and steaks will have an appetizing aspect, and translucent flesh. Good knifework makes a difference too—steaks should be cut evenly so they cook evenly, and each steak should be the same thickness.
As fillets and steaks begin to age, the translucent flesh turns opaque. A slippery feel and a shiny surface on otherwise opaque flesh probably means that the fish has been treated with sodium tripolyphosphate (STP). Used to retard bacterial growth and moisture loss, STP can also suppress a fishy odor, but it adds a chemical taste to the fish. Fish processors commonly treat fillets with these additives, but they rarely inform their customers. If the quality of the fish is excellent to begin with, however, there’s no need to use STP or any other additive.
A good fish market has rapid turnover and, like good fish itself, shouldn’t smell fishy. The labeling should be precise (“sockeye salmon steaks”) instead of general (“salmon”), and the seafood should be well iced, with fin fish displayed separately from shellfish, to prevent bacterial contamination. Finally, the staff should be knowledgeable about its products and make good culinary recommendations.
With all these requirements, is it possible to buy good fish in a supermarket? For years, the answer was definitely not. However, many supermarkets, even in the middle of the country, have worked hard to develop credible fish counters. If the store’s seafood department is separate from the meat department, staffed by professional fish people, it can be every bit as good as or better than an independent market.
If you do buy at a supermarket, don’t be put off by plastic-wrapped self-service fish. The fish in a tray pack is handled less than the loose fish behind the counter, and it’s likely to receive better temperature control. If the quality of the fish going into the tray pack is first-rate to begin with, it can be just as good as fish purchased at the service counter.
The most important thing is to keep the fish as cold as possible. If you aren’t going straight home from the market, or if you have a long trip, ask the fishmonger to pack a bag of ice with your fish. As soon as you get home, transfer the fish to your refrigerator. Put fillets and steaks in a plastic bag and set the bag on ice to maintain a temperature close to 33°F (spoilage occurs twice as fast at 40°F as it does at 32°). Avoid freezing fish at home—most residential freezers don’t freeze fast enough, which causes large ice crystals to form in the cells, damaging the flesh when it thaws. Instead, buy only what you need and use it as soon as possible.