According to Cimarusti, the "frozen/defrosted" label on a lot of fish at the market these days means you're going to end up with fish that's less fresh and that has a chewier, more rubbery texture. "The only argument you can make for freezing is the cryogenic freezing that's done in Japan," he says, "although they've done that to preserve a lot of unsustainable bluefin tuna." Translation: You shouldn't be eating unsustainable fish anyway. "If the fish was frozen fresh and beautiful, it should come out that way, but the texture does change. Freezing at sea is becoming more common these days as boats are out on the sea longer to get the fish we want." This has to do with our changing environment and overfishing, but is it possible that every fish being sold to consumers has been frozen at one point or another, even if the store or restaurant doesn't admit to the act? "Not necessarily – there are certain varieties at, say, a sushi restaurant that you know will never be frozen," says Cimarusti. "Albacore, however, often gets frozen in blocks before it's cut and prepped as sushi. Salmon, too. There are also companies that sell hamachi that are filleted and frozen. Our fish comes in fresh; it has often died in the last 24 hours." Squid and octopus do well with freezing, however, according to the chef.
Cimarusti says he once worked in Kyoto, Japan, at a place that bought fish for its lunch service and kept it in live tanks. "The fish would relax in these tanks for a day, and then the chef would take them out and perform a special Japanese technique to kill them, which renders it more tender," he recalls. "They pass a stainless steel rod into the spinal chord of the fish, which kills it easily. If you just whack the fish dead it can have an unpleasant chewiness."