The Japanese ripening technique for large fish has been reinvented by Koji Kimura, who begins the process in the same market. «I touch them», confesses the chef considered the greatest expert in this process today. «I am Andrés Iniesta of sushi», is presented in the kitchen of Reale Seguros Madrid Fusión, and makes another confession: never buy tuna caught in Japanese waters. One of his favorite species is swordfish, which can ripen up to 90 days. The tenderloin that has brought to the gastronomy congress for the attendees to try had 50 days of drying. “The darker the meat is, the longer it has been maturing. That soft fish I always place on hard rice, to generate a contrast of textures. The sensations increase like this ».
That tradition of maturing fish with vinegar and salts has been investigated by Kimura to combat the stereotype, he says. “For years the same type of drying and fish was used, and people say that sushi is a sheet of fish on top of rice. I do not. I have created my own ripening technique to soften the meat. With hard cooked rice and with that very soft meat I have created my own style ».
The goal of ripening techniques is to subtract all possible moisture from the fish. “It’s the cause of the bad smell, that’s why the salt process is very important,” says Kimura Sushi’s chef. The first step to this fluid withdrawal is to remove the blood from the main vein. For that, cut the tail and divide what is left into two meridians. With an injection with electrolyzed water pushes that blood. “This is the most important thing to eliminate the bad smell,” he reiterates. Then it is immersed in salt water. A small fish can be in this 3% solution for four days. It is cleaned with paper to absorb all other water and filleted and covered with more salt, about ten hours. Large specimens require more time.
One of the diners defined the sushi offered as “silk.” The Tokyo chef then shares another secret: «The swordfish is a greasy fish and to stabilize its flavor, next to that of rice, I give it a touch of vinegar. It has coffee and fruit aroma. But you can get another type of aroma by getting the maximum umami ».
Nevertheless, Kimura’s big secret is pampering with the knife’s edge. The “oxidation” is cut every two days, a film of meat that covers the piece. Kimura the slice is less than a millimeter thick. “Leftovers serve to make soup,” he maintains. Thus, monitored every day, thinned by this care, it can be up to 90 days. Increasingly soft and dark. “My masterpiece is the swordfish from Japan, which is a very large species,” says ‘Andres Iniesta of sushi’. Last trick: after stripping the meat with excess salt, it must be wetted with soy sauce after 40 or 50 days after ripening. A goal that is worth a World Cup.