With almost surgical precision, the chef cuts a fillet from a tuna weighing around eight kilos. Meanwhile, Walter Sidoravicius, a renowned Michelin-starred chef based in Ibiza, explains how to identify the correct shade of tuna to ensure quality and demonstrate the correct way to cut it into pieces for a sushi dish.
Sidoravicius — Venezuelan by birth, but with German and Lithuanian parents — is one of the world's leading experts in preparing this popular dish. He has been making sushi for 16 years: after training in hotel management, he worked in Japanese restaurants around the world before moving to Japan to further his training. Now, when he is not in charge of his Michelin-starred restaurant in Ibiza, he offers a masterclass in which he shares all his knowledge and experience. Twenty students attended the training offered at the Escuela de Hostelería on Monday morning, taking notes and paying close attention to his explanations.
Quality
It is very important that the tuna does not suffer when it is slaughtered. If it suffers a lot of stress just before it dies, it gets a metallic taste and a more greyish tone, which the Japanese call yake.
«The tuna, if it is a quality tuna, has to have a reddish tone inside", explains Sidoravicious, outlining how to recognise a quality piece of tuna, something he considers elementary for preparing good sushi. A preparation that during this day has been prepared with bluefin tuna caught in the seas off Ibiza. «Tuna that thrives in the wild is of higher quality than tuna caught on a farm, because its diet is richer and more varied, just like beef», explains the chef.
After an introduction to the subject, the practical part begins: processing and preparing the fish. With unquestionable mastery, Sidoravicious proceeds to make the cuts. The thickness of these cuts determines the name of the final product: sashimi is 14–16 mm thick, nigiri is 12–14 mm thick, and usuzukuri is approximately 9–12 mm thick.
Once the pieces have been prepared, with the tuna already cut and nothing wasted - the layer closest to the skin can be used for makis or tartar, he assures us - the different preparations of the tuna are produced.
The first of these, perhaps the simplest, is shiozuke, which is marinated in salt and has to be in the cold store for around 20 minutes. The next, maguro zuke, in which the tuna is blanched and then placed in boiling water. Next, tataki, where the tuna is cooked in a very hot frying pan ‘to give it that smoky flavour’ and then marinated.
Presentation
Once the product has been prepared, it is time to adapt it to the dish and how it will be presented. In this case, the chef has opted for a nigiri, where the tuna is placed directly on the rice, and a maki, where the tuna is rolled around the seaweed. The futomaki has been used as an example of this.
«The seaweed has two sides: a shinier side that goes on the outside and a rougher side that goes on the inside,» the chef explains, demonstrating how to prepare the rolls. This is just one of the many tips he has offered for preparing this dish correctly. He highlights that «the rice must be hydrated with water until it is completely white and not transparent at all».
These and many others are the tips that some twenty people, whether professional chefs or sushi enthusiasts, obtained during a day in which they ended up preparing their own creations. Without the mastery of Sidoravicious, but with a great desire to learn, many have ventured into their first nigiris and makis.