JIRO DREAMS OF VEGGIES
‘Vegan Sushi’ Turns Tomatoes Into Tuna
With the fishing industry endangering the world’s finest tuna, one sushi chef is turning to tomatoes as the solution.
You know we have a problem when Jiro Ono, the world-famous sushi chef of Jiro Dreams of Sushi fame, sees a need for sushi to adapt. “I can’t imagine at all that sushi in the future will be made of the same materials we use today,” he told the Foreign Correspondents Club of Japan.
“I told my young men three years ago sushi materials will totally change in five years,” he said. “And now, such a trend is becoming a reality little by little.” One such trend is that sushi is shifting away from high-end tuna, a staple of Japanese cuisine.
It might sound like I’m exaggerating here, but I’m not—the southern bluefin tuna is near extinction. While all three species of bluefin tuna are greatly overfished, only the southern bluefin is on the International Union for Conservation of Nature (IUCN) catalog of critically endangered species. This rating is just one step below “extinct in the wild” and at the highest possible level of threat available on their “Red List of Threatened Species.” Greenpeace is a bit more forceful on their own “red list,” recommending that you shouldn’t buy southern bluefin tuna under any circumstances, pretty much ever.
According to the most recent assessment in 2014, the southern bluefin tuna spawning biomass—what scientists call the amount of fish actually able to reproduce—is at less than 9 percent of the original stock. For every 10 fully-grown bluefins that were in the ocean before we started fishing them, we’ve eaten all but one.
Tuna didn’t face many threats before we came along—they’re apex predators, the lions of the ocean. This explains why their mercury content is so high compared to other species of fish (the fish at the bottom of the food chain have the smallest mercury concentration, the next level up gets the accumulated mercury from all of the fish it eats on the lowest level, the next level up gets all the accumulated mercury from the fish on the lowest two levels, and so on and so on) but also why tuna are so vulnerable to overfishing.
With no predation, tuna are able to grow slowly, and they grow big. Southern bluefin tuna typically get to be more than 8 feet long and can weigh up to 600 pounds. In the wild, it takes up to 12 years to reach sexual maturity but only three years to reach the size they are when they’re typically caught, about 30 pounds. This means that most of any given catch of southern bluefin hasn’t gotten a chance to reproduce. It’s a recipe for unsustainable fishing.
While current projections are somewhat optimistic—we’ve reduced our fishing enough that stocks are growing again, albeit slowly—the Pew Environmental Group advises caution. They wrote this past December that, “[W]hile any growth in the population is good news, even a doubling in numbers of a severely depleted species leaves only a slightly less severely depleted species.”
The ocean won’t be able to keep up if demand stays constant and populations continue to rise—China’s burgeoning middle class is already creating a strain, since they consume the most southern bluefin tuna behind Japan and the U.S. According to the IUCN, the population will be down to fewer than 500 mature fish in 100 years if trends continue.
Enter James Corwell, a certified master chef with an alternative he hopes will change the way we eat and think about fish—tomato sushi.
When he first visited Tokyo’s Tsukiji fish market in 2007, Corwell was an instructor at the Culinary Institute for America, teaching chefs in the Air Force and the Navy. He saw firsthand the scope and scale of the largest fish market in the world and had what he described as “an a-ha moment.”
“There are literally two giant warehouses that fill up with bluefin tuna from all over the world,” he told me. All of that fish, more than 2,400 tons of it, pass through the Tsukiji market every day. “This happens day in and day out, year after year. How can the oceans possibly keep up? They can’t.”
I asked Corwell if this was his Road to Damascus moment. “It was a snap conversion in that I realized there needs to be an alternative,” he said. “How that alternative came about took time and a little bit of knowledge. What really mattered, I came to learn, was a non-essential amino acid called glutamic acid.”
A German chemist discovered glutamic acid in 1866 and it was isolated as a crystalline salt by a Japanese researcher in 1908. This salt, monosodium glutamate, or MSG, is a common food additive and flavor enhancer. It creates a mild savory flavor that lingers on the tongue, commonly associated with fish, cured meat, green tea, soy sauce, and some varieties of cheese. It also occurs naturally in ripe tomatoes.
Corwell explained to me that there are five essential flavors, but the West typically only uses four. “We work with sweet, sour, salty, and bitter,” he says. What makes Japanese cooking distinctive is their emphasis on the savory, or umami. “They cook with the idea of savory throughout the beginning and the end of the dish.”
While there are a host of vegan and vegetarian varieties of sushi, they tend to be extremely westernized, using vegetables like sweet potatoes, cucumbers, avocado, or asparagus. There are few if any options that have umami flavors, and nothing to offer which might match the texture and feel of raw fish. That is to say, there isn’t much that seems at home in a traditional Japanese dish. That’s where tomato sushi comes in.
The umami flavor occurs naturally in tomatoes, and Corwell enhances that flavor with salt, vinegar, and sugar (a time-tested combination familiar to any ketchup enthusiast). The color, of course, is naturally there. The texture, though, requires a bit more work. Salt and vinegar help the firming process, but Corwell also cooks the tomatoes sous-vide, a technique that involves vacuum-sealed baths in controlled temperatures of hot water.
I tried a few pieces of the final product, and it’s convincing. The texture and look is spot-on, and a friend couldn’t tell the difference between tomato sushi and raw fish (for what it’s worth, I could, though that hardly made it less delicious). “It’s never going to taste exactly like tuna,” Corwell told me, but that doesn’t seem to be his focus. “It looks like a real dish and gives you a great sushi experience.”
Last fall, Corwell Kickstarted tomato sushi, raising more than twice his goal. Moving forward, he’s less interested in getting the sushi into restaurants, though, and more interested in bigger targets. “I think the way to go is to partner with large operations, the Apples, Googles, Cornells, Stanfords, Berkeleys, places where there are large communities of socially conscious customers who would identify with this and want to have an option to make a difference.” Working to change small markets and restaurants is time-consuming and expensive, Corwell explains. “Working from the top down is our best way.”
It’s hard to deny that the sushi industry needs to undergo serious changes. As an undergrad, I profiled my favorite restaurant, Miya’s Sushi, which bills itself as the Northeast’s only sustainable sushi restaurant. Most dishes are consequently vegetarian, and the seafood on the menu isn’t your typical sushi fare. There are no shrimp, eel, or tuna stocked in their kitchen—much of what they serve is either an invasive species or an often-overlooked fish caught or farmed locally. Nonetheless, it’s one of New Haven’s most popular restaurants.
So long as there are talented and socially conscious chefs making delicious food, we can start to undo the damages caused by an irresponsible food industry, little by little, tomato by tomato.