So I am a new member here and this is my first post. I love foods of all kinds, but am crazy about sushi. Having travelled abroad to Japan I am very familiar with the taste and texture of authentic sushi, and miss it everyday. Its a shame that here in NYC, to get a similar experience I would need to fork out $100+ for a decent omakase.
After watching Jiro Dreams of Sushi, I was motivated to try making sashimi and sushi myself, starting with the basic tuna. I went fulton fish market to find the freshest tuna, where I could see the fishmongers cutting and filleting a full tuna into large pieces. I bought myself a nice large piece with great color and a little bit of fatty chutoro. I remember in the film Jiro mentions aging tuna for 4-6 days, but had no idea what that would be like.
After bringing the tuna back home, I began cutting it into blocks while following youtube videos, and at the same time tasted the raw fish. I thought, "this is the freshest that I can get, it should taste amazing" That first bite I took changed my world forever, because instead of the delicious, tender, clean tuna I expected, I got a mouthful of fishy/briney tuna with the metallic taste of blood. The texture was so different, firm and chewy, which combined with the bloody, fishy taste, was just an awful experience. It tasted like raw fish in the worst possible way.
So next my goal was to age them a few days, so I cleaned the surface with a paper towel and repacked the blocks every day. It was definitely a labor of love. By day 3, the blocks looked less red, and the texture was different, so I cut into it and tasted. The texture was similar to high quality tuna, and the metallic, fishy taste had disappeared. Instead it transformed into a subtle, clean, taste that was very delicious. In addition, the texture was perfect, turning into the iconic mush-chewy texture and not the firm-chewy texture of before. It tasted pretty damn good.
I guess my question now is, how do the professional chefs in Japan (or sushi bars here in USA) prepare fresh Tuna? Are there any marinades or other prep work besides cleaning and cutting? It would be great to hear some advice from a professional chef.