The Story of Sushi

by Trevor Corson

  Today, most sushi bars serve two types of shrimp: raw, fresh tails, which are glistening, transparent, and sticky; and smaller, cooked tails with meat that is firm and white with pink highlights. Sushi bars in America usually list the former as ama-ebi, or “sweet shrimp.” In Japan people call them ama-ebi or botan-ebi. They are relatively expensive. The smaller cooked shrimp usually go by the name kuruma-ebi, or just ebi, and are cheaper.

  The smaller, cooked shrimp are generally of the black tiger or Mexican white varieties. Environmentalists decry the methods that produce these animals. Fishermen catch them with trawl nets that also snag nontargeted sea life, including baby fish and endangered sea turtles, although U.S. fishermen have taken steps to minimize such by-catch. Overseas farming operations have destroyed millions of acres of mangrove habitat to grow these shrimp.

  The larger sushi shrimp, served raw, are generally of the spot prawn or pink shrimp varieties that belong to the genus Pandalus. Fishermen harvest them from the wild, mostly with traps or trawls that are far less damaging.

  Every Pandalus shrimp starts out male. He spends his first two or three years as a bachelor, during which time he generally loses his virginity. Once he’s had his fun, his testes transform into ovaries and he matures into a female. At which point, she turns around and hits up the new generation of strapping young males for more sex. There is some evidence that if females are especially numerous, the males can delay their sex change and remain playboys for an extra season or two. Likewise, if there aren’t enough females, the males may give up their bachelorhood and switch early.

  The shrimp Marcos was working on were tiger shrimp tails, recently defrosted. Three other students joined him and helped insert skewers. When they had finished, the result looked like a bowl of seafood Popsicles. Zoran strode into the kitchen and glared into the bowl.

  “What the hell is this?” He picked up one of the shrimp. It was still curved.

  “Probably one of mine.” Marcos said.

  “Come on, man,” Zoran spat. “What’s the point if it’s not straight? I showed you how to do it.” Zoran folded his arms across his chest and stepped back.

  “Marination is up to you guys,” Zoran said. “I’m not going to say anything.” He strode away.

  One of the students remembered Zoran’s saying that the sweet vinegar from a bucket of pickled ginger was favored by many chefs. They agreed that would work. First, the shrimp would need to be briefly blanched. Marcos dumped the skewered shrimp into a pot of boiling water.

  Crustacean flesh develops delicious aromas and flavors simply by spending a few minutes in boiling water. Most meats can’t achieve such high levels of smell and taste without the application of flame or intense heat, and there are a couple of reasons for this. Crustaceans counteract the osmotic pressure of saltwater with an especially tasty and concentrated array of amino acids, particularly the same sweet-tasting glycine found in mackerel. Crustacean flesh also contains a high concentration of sugars. With the application of a little heat, these amino acids and sugars react with each other, creating the same sort of delicious and aromatic molecules produced in the meat of mammals and most fish, only at much higher temperatures.

  When the students’ shrimp had floated to the surface, the flesh had turned from transparent to opaque. Marcos hefted the pot off the burner and hustled it toward the sink, shouting as he moved, “Hot pan!”

  He’d underestimated the weight of the water. When he hit the edge of the sink his skinny arms couldn’t lift the pot over it. He pushed it against the side of the sink, trying to force the top over so the water would spill out. Steam billowed in his face. Zoran was screaming at him.

  “Quick! Quick! So they don’t keep cooking!”

  Marcos spread his legs, grimaced, and shifted sideways to get a better grip. Finally, the water streamed out with more clouds of steam. Then he dumped the shrimp into an ice bath. He wiped his brow and carried the bowl out to the classroom.

  “Well,” he announced, “we’ve got some semi-straight shrimp.”

  That was only the beginning. Several students gathered around the bowl to remove the skewers and peel the shells off the shrimp. Then, they sliced off any irregular flesh at the head end to create a neat, straight line. They trimmed the tail flippers at a prescribed angle. They carefully sliced at the belly tendons until they could spread the shrimp flat in a butterflied position; if they sliced too deep, they’d cut the shrimp in half. Zoran hovered over them, offering pointers.

  “You don’t need to marinate shrimp for sushi,” he said. “Often chefs in Japan don’t. But Americans like everything sweet.”

  But you do have to wash the shrimp because they are full of shit. Takumi rubbed each of his shrimp in a bowl of saltwater, scraping his thumb along the shrimp’s tiny digestive tract to remove it. Most of the other students forgot, leaving their shrimp laced with poop.

  Zoran stood at the head of the table, overseeing the assembly line. “When you guys start working in a sushi bar, this is what they’re going to have you do first thing. Lots of sushi ebi.”

  Finally, they dumped the shrimp into a couple of bowls of pickled ginger vinegar to marinate.

  Takumi switched on the lights over the back sushi bar, and the motley crew took their stations for the Monday lunch counter. They were open for business.

  Marcos remembered the rush he’d felt at the Paramount Pictures party, when hot girls had flirted with him at the sushi bar. But since then, he hadn’t been able to use his status as a sushi chef to meet any hot girls. He was 17. If he were a Pandalus shrimp, pretty soon he’d be losing his testicles.

  Sushi was the bait, and now he had some skills. He squeezed together a California roll and a spicy tuna roll and put them on a plate with a dish of soy sauce. He stood out on the sidewalk in his chef uniform and tried to look handsome.

  Two women walked toward him.

  “Heyyyyy,” Marcos drawled, “you ladies want some sushi?”

  “Thanks, we’ve already eaten.” They eyed the plate. “Did you make this?”

  “Yeah!” Marcos plugged the restaurant, but they walked on.

  A pair of very pretty girls approached, purses and cellphones dangling. “Heyyyyy, you ladies want some sushi?”

  The girls smiled. “No, thanks!”

  Marcos gazed after them, forlorn. “Maybe I’m just not cute enough.”

  After five minutes Marcos gave up and retreated inside. “Wow,” he said, “marketing is a lot harder than it looks. I thought everyone out there would want to eat free sushi.” He thought for a moment. “Maybe we need to get a commercial on Fox.”

  Bored and hungry, Takumi sliced a few thin pieces of tuna and disappeared into the kitchen. Alone, he spread fresh tomato paste on the tuna, drizzled it with olive oil, and sprinkled on chopped chives and garlic chips—Italian carpaccio. The Japanese weren’t the only ones who ate raw tuna. He scarfed it down.

  At the sushi bar the students were discussing what it was, exactly, that they were supposed to yell when a customer came in. The workers at the Subway sandwich shop across the street had it easy. All they had to do was yell, “Welcome to Subway!”

  “It’s ee-RA-shee mase,” Marcos said.

  “I don’t know,” Kate said. “I just wait till everyone else is yelling it, and then I go, ‘Ra-ra-ra-ra.’”

  Just then a pair of attractive women walked in. Nearly in unison, the students belted out an approximation of “Irasshaimase!” The women sat right in front of Marcos. Now he just needed to impress them with his sushi skills.

  Marcos cleared his throat and greeted them, a quaver in his voice. The women ordered albacore nigiri. Marcos pulled the albacore from the neta case, his fingers trembling.

  “So,” the brunette asked Marcos, “how long have you been doing this?”

  “About six weeks, I guess,” Marcos said.

  “We used to come here all the time,” the brunette said.

  Marcos turned up the charm. “Well, we’re glad you’
re here.”

  Marcos squeezed together four nigiri. He crammed them onto a plate that was much too small. He forgot to sauce them. He handed the plate across the bar. The brunette handed it back. “Could we get some sauce on these?”

  Marcos blushed. He dabbed a blob of sauce on each piece of fish. The brunette popped one in her mouth. She grimaced and squeaked out a noise that suggested revulsion.

  Marcos looked terrified. “Too much wasabi?”

  “No,” the brunette said. She fished around in her mouth with her fingers. “There was a bone in there.”

  “Oh.” Marcos hung his head. “Sorry.” Regardless of who prepared the fish, it was the responsibility of the chef who served it to ensure it was suitable to eat.

  Kate’s mother came, this time with Kate’s brother. Kate served them a fancy roll.

  “This is very pretty, baby,” her mother said. Kate smiled.

  Later, her mother snuck up to where Kate was working and snapped a photo. Kate rolled her eyes. “Mom!”

  Afterwards, Kate grabbed some cucumbers, rice, and nori, and headed home to practice her rolls.

  22

  GETTING FISHY

  “Everybody ready to get fishy today?!” Zoran yelled the next morning. “From here on out, fishy, fishy, fishy!” He had an evil grin on his face. “You’re going to need to know the Japanese names for every single part of the fish,” he said. He peered down the table. “And Takumi, you’ll have to know the English names.” Zoran went on. “If the sushi chef says to you, ‘Sji sakana,’ he means clean up the fish. Not fillet. Just clean up. Take out the gills, the guts.”

  More guts? Kate steeled herself. This time she didn’t want Zoran telling her that she “hadn’t prepared her fish properly.” She was sick of being the class flake.

  Zoran drew the outline of a fish on the whiteboard. He labeled all the fish parts on the diagram with their Japanese names. The students scribbled furiously in their notebooks. Zoran set out a cardboard box on the table with a thud. Mackerel again.

  “Saba! Today, we are going to make saba sushi—and sashimi.”

  In the old capital of Kyoto, mackerel was one of the most common fish used in early Japanese sushi, back when chefs pressed entire fillets of fish onto sushi rice in boxes with heavy stones. But mackerel was never used raw for sushi. Nor was it used cooked.

  “We usually marinate it with salt and vinegar,” Zoran said. “The thing you should know about saba is that it’s susceptible to parasites.”

  Mackerel is perilous to serve raw. Mackerel is so difficult to keep fresh that Japanese chefs sometimes call it the fish that “spoils even while still alive.” Humans can also pick up more than fifty different parasites from eating raw or undercooked fish; removal of parasites can require surgery. A worm called anisakis is one of the most prevalent parasites, and its larvae love living inside mackerel.

  The clever larvae of anisakis swim around looking delicious. They want to be eaten, and usually a small crustacean will oblige. The larvae live happily in the stomach of the shrimp or krill until a mackerel comes along and eats the crustacean. Then the larvae burrow into the lining of the fish’s gut or, less often, into its flesh.

  Mackerel serve the larvae’s purpose only because sooner or later a mammal will eat the mackerel, preferably a dolphin, porpoise, or whale. Once in the stomach of a mammal, the larvae molt and become adult worms. The worms use a mouth like a boring tool to drill into the mammal’s stomach wall. They mate and lay eggs, which emerge in the mammal’s feces, starting the cycle again.

  The larvae can end up in a human stomach just as easily as in a dolphin stomach. When a human eats an infested fish without cooking it, he feels a tingling in the throat, and within a few hours may suffer violent abdominal pain and nausea. If he’s lucky, he’ll vomit up the larvae.

  If not, he’ll suffer for a week or so until the worm, realizing that it’s not inside a dolphin, gives up and dies. By then, the person’s doctor may have misdiagnosed the situation as stomach cancer. Even without swallowing a live larva, people sometimes react simply to the chemicals in the fish that the larvae produced.

  But heat kills the larvae easily. Some people would argue that grilled mackerel smells and tastes so delicious that there’s no point in risking anisakis illness by eating it uncooked.

  Nevertheless, sushi chefs continue to prepare and serve mackerel uncooked. In theory, salting the fish and then soaking it in vinegar may well kill the larvae, for the same reasons that salty and acidic environments kill bacteria. Salt sucks the water from cells, causing them to shrivel. Acids bombard cells with hydrogen ions, warping their enzymes.

  Unfortunately, experiments have shown that parasitic larvae can survive for nearly a month in a 20 percent salt solution. Japan has one of the highest incidences of anisakis illness in the world—about 2,000 cases a year.

  “Saba is also very oily,” Zoran added. “About sixteen to twenty percent fat. The marination helps cut down on the oil. Saba also has a very fishy taste.”

  Fish that are alive, and fish that are freshly killed, don’t taste or smell fishy at all. A perfectly fresh saltwater fish emits two primary smells. One of these smells is the scent of the ocean—or rather, of the bromophenols produced by algae that fish eat. Surprisingly, the other smell is the odor of geranium leaves. The fats in fish are the unsaturated kind, as they are in plants. Fish skin and plant leaves both contain an enzyme that breaks unsaturated fats down into fragments that smell “greenish” and a bit metallic, like a newly crushed geranium leaf.

  Soon after death, however, fish start to smell fishy. Fishiness comes from the same phenomenon that gives fish much of their flavor. In their fight against the osmotic pressure of saltwater, sea creatures fill their cells with tasty amino acids. But fish in particular also fill their cells with a related amine called trimethylamine oxide, or TMAO.

  Unlike the amino acids, TMAO has no taste. Nor does it have any smell. But after the fish dies, bacteria on the fish, and enzymes in the fish itself, steal the oxygen away from TMAO, leaving behind TMA.

  TMA by itself stinks. It’s what gives old fish their foul smell. It’s also present in human bad breath and in bacterial infections of the human vagina. A rare genetic disorder called trimethylaminuria can prevent people from metabolizing routine amounts of TMA in their food. The devastating result is that their sweat smells like rotting fish. For obvious reasons, it’s a disorder that can cause severe depression.

  In addition, bacteria on the surface of the fish quickly digest proteins in the fish after death, creating noxious fumes, including ammonia, putrescine, and cadaverine.

  Salting and marinating fish with vinegar doesn’t just help control parasites. It also reduces fishiness.

  Covering fish with a heavy layer of salt draws moisture out of the flesh by osmotic pressure. As the water inside the flesh rushes to the surface to dilute the salt, compounds like TMA and stale-smelling fatty acids emerge along with it.

  Meanwhile, the acetic acid in vinegar fires hydrogen ions at TMA, just as it does at bacteria. When a hydrogen ion hits a molecule of TMA, the fishy-smelling compound gains a positive electrical charge, which allows it to dissolve easily in water, removing it from the air and terminating the smell.

  Mackerel were not the only fish that early sushi chefs salted and marinated. In fact, the sushi vendors on the streets of nineteenth-century Tokyo rarely served anything raw. They had no access to refrigeration. They salted and marinated—or blanched, or seared—all their seafood so it would keep long enough to serve. Sushi chefs in old Tokyo used so much salt and vinegar that people called sushi shops tsuke-ba—“pickling places.”

  The need for preservation generally had a fortuitous effect; salting and marination often improve the taste and texture of raw fish. One of the reasons for this is that muscle, like mold, contains a lot of enzymes. In muscle, enzymes convert fuel—sugar—into energy. Fish muscle, however, generally contains many more enzymes than the flesh of land animals.


  This is partly because fish of many species lead lives of extraordinary self-sacrifice. They consume as much food as they can, building up their muscles and fat reserves, and then they embark on long, grueling migrations. Toward the end of these migrations they manufacture huge masses of sperm or eggs. When they run out of fat during these mating marathons, they literally start to eat themselves for the sake of the next generation. The many enzymes in their flesh deconstruct their own muscle proteins into amino acids. The fish can then use them for energy and the raw material for building sperm or eggs. The closer the fish get to spawning, the more wasted and frail they become.

  Like the enzymes in mold, the enzymes in fish muscle continue functioning even after the fish dies. As a result, cooking can actually ruin the taste and texture of fish. If you heat a piece of fish at too low a temperature for too long, the warmth speeds up the work of these cannibalistic enzymes, and the fish eats itself right there in the pan. As with crustacean meat, the result is mush.

  Salting raw fish at room temperature, however, lets the enzymes work slowly, deconstructing a little of the protein into the tasty components of umami. The salt fends off bacteria long enough for the enzymes to accomplish their task, and the salt itself amplifies the effect of umami on the human tongue.

  Mackerel flesh digests itself to the peak of umami in about twenty-four hours after salting. Any longer and the umami degrades. Before the advent of modern transportation, runners from the coast of the Japan Sea carried 100-pound boxes of freshly salted mackerel to the inland city of Kyoto on foot. They hiked all night along thirty miles of mountain paths so that the fish would arrive just in time to reach their peak level of umami.