Some fish, even if they are to be served raw like for Sushi or Sashimi, can benefit from aging. “What, aging fish?!” That’s what I thought when I first started as an apprentice sushi cook. Like everyone, I thought all the fish are best eaten right out of the water, fresher it is, the tastier. Turns out that is not true…

Madai for instance, is best around the third day from the catch. A large Tuna (we are talking about 200lb and bigger) is most delicious after about a week or 10 days from the catch. I am not suggesting leaving the fish laying about for days after the catch, and of course one must properly treat the fish right out of the water in order to age them.

Lets take Hirame for example, one of the lightest and most delicate tasting fish. A typical routine for chefs in Japan is to go to the fish market every morning and choose the fish according to the quality and price. The fish at the market are all caught the night before, and have been killed swiftly and bled properly on the boat right after the catch. One can easily tell that by the clearness of the eyes, stiffness of the fish and the condition of its skin. Once the Hirame is brought back to the kitchen, they are cleaned before aging. The degree of cleaning depends on the chefs’ preference. Some only clean the gut and de-scale them. Some will de-bone. Once cleaned, they are normally kept in fridge for 3 days before showing up in the Terashi (Sushi display case) for customers. In three days Hirame will be much “sweeter” and have more umami. Most respected sushi restaurants will not even serve Hirame caught the same day even if they run out of the aged ones.

With tuna, the aging process takes even longer. When tuna is well aged, the meat becomes very tender and fragile, this is the reason many chefs use Takohiki, a special thin blade knife to cut aged tuna for sushi or sashimi. A dab of fresh wasabi on the aged tuna with a bit of Shoyu (soy sauce) on the corner and you have a most satisfying complex savory fish swimming in a flower garden (fresh wasabi that is) in your palate.

The proprietor of one of my favorite fish restaurant Le Tiboulen de Maire in Marseille France goes even further. He instructs the fishermen where to fish –as he knows the local water very well- and even how to catch the fish. All his fish are line caught, no nets. He says when fish are caught by net, there are other fish in the net and some fish eat one another resulting in fish with full stomachs. He prefers his fish to have empty stomachs because when he ages his fish, he leaves the fish intact without even cleaning the inside. He tells me that he will not even let the fish touch fresh water or ice. Just right out of sea water, properly killed and bled, and kept in the fridge for 2 to 3 days before grilling. The result is amazingly flavorful grilled St. Pierre, and one can even eat the grilled liver after 3 days! That liver of Grilled St. Pierre alone is worth the trip to France.

On the other hand, not all fish should be aged. Generally speaking, shellfish and small sized high oil content fish such as Iwashi and Aji are best when it’s super fresh. A squid is actually clear as a crystal right out of the sea. Transparent squid like that are so sweet and crunchy as sashimi, but within 20 minutes the flesh will become milky in color and start loosing its flavor and texture. Uni right out of its shell is much sweeter and delicate then the ones we normally see in the boxes. Fresh Aji Tataki with ginger and green onion is to die for. And some Japanese fishermen will de-bone fresh caught sardines by hand, chop them up and mix them with miso, ginger, and green onions, then place the mix over hot steamed rice and make Iwashi Tataki Donburi!!! I’ve had the same dish, but on land, and it was by far the best sardine dish I’ve had in my life. I can only imagine how it will taste on the fishing boat…

Daisuke Utagawa

Madai = Red Seabream

Hirame = Large-tooth flounder or Left eyed fluke.

St Pierre = John Dory

Iwashi = Sardine

Iwashi Tataki = roughly de-boned and chopped Sardine tossed with fresh graded ginger and chopped green onion.

Aji = Horse Mackerel

Uni = Sea Urchin


Le Tiboulen de Maire

Chemin des Goudes – 13008 Marseille

Phone +33 4 91 25 26 30

  1. Kai says:

    Hi Utagawa-san,
    this might be an old post but here’e hoping you see this. Was wondering when one ages tuna, O-toro in particular; does one age it in sakus or does one age it in whole portioned-loin sections? Been trying to find out more since different places use different methods and I thought you might have valuable input to this topic. Thanks.

  2. snow says:

    Thanks you for the aging progressing infirmation. I have been interesting to learn about how to age fish to make sushi for a while now and this article is the first one i was be able about aging fish. I would love to know more about information about this. I am greatly apperiate for your knowlege and have share a wonderful piece information with us. 🙂

  3. dukebirdy says:

    Hello Kai,

    Sorry for my late reply. I have not written new post for a while so I did not see your comment/question.

    In general, I find it better to age tuna in large chunks, not in saku to avoid oxidation of the meat.

    Thanks for reading my blog!


  4. […] in sushi. There are several factors that go into a great bite of sushi such as ikejime and “aging the fish.” (tl;dr: freshly-caught fish doesn’t have much flavor until the tissue degrades to a […]

  5. Richard says:

    Daisuke, I just stumbled across your blog today and look forward to reading more of your postings.

    I heard that fish used for sushi and sashimi are slightly different (even within the same species) as fish used for sashimi have a firmer texture and that for sushi a slightly softer texture (so that it complements the rice better). I understand that the difference might be attributed to how the fish is aged.

    Any insight you can share on this point?



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