How to prepare fish for aging



With Ike-Jime closing, moderate cooling, and proper cleaning, you can enjoy your fresh catch for days without freezing. The tasty period of my common catch here in Okinawa, for example, would be small tunas for 2 days, amberjacks for 4 days, snappers for 5 days, and groupers for 6 days.

In this post, I’d like to discuss how to clean fish to prepare for aging.

Here is the video to start with. I’m not a professional chef. But here’s how I do it.


3-0335-13Since I found this Ginrin Fish Scaler, scaling has became so much easier for me. The sharp edged cup slides under scales and lifts them off. Because it doesn’t flick off scales, you don’t mess your kitchen with flying scales. Of course you will get a few, but as a matter of fact, my wife used to forbid me scaling in the kitchen but she allows me now. That is a huge difference! I know many anglers around the world would agree with me on that. The scaler also has jaggy edges on both sides of the cup and these work very well around the fins.

I have it for sale at JPY2692 + shipping and handling.

Ginrin Fish Scaler Professional →

Or, you can just send me your message to order through contact form.


I have cut the head off in the video but you don’t have to at this point. In fact, you better not to. You should make the least possible cuts on fish when you age fish. If you leave the head on, make sure to take out gills and clean blood chunks around the head thoroughly.

But a lot of times I find that cutting the head off at this point will just make everything easy. Storing will be easy. Cleaning the head will be easier when it’s separated too.

I love to cook the fish head by the way. I think the most tastiest meat is concentrated in the head. Neck has such silky texture. Cheek is delicate and awesome. Around pectoral fins is juicy flaky meat. I’m not a big fan of eye sockets, but it contains lots of essential fatty acids like DHA, which are not to be missed.
I usually cut the head off at this point. Clean and store separately.

Brush off blood

Blood is bad. Yes, that’s the code.

There’s a major blood vessel running on the belly side of the spine. When you open the belly and take guts out, you will see air bladder. When you cut it open, you will see reddish black blood vessel on the spine. You want to thoroughly clean this with a toothbrush or a bunch of toothpicks. This is very important process when you age fish. Without complete cleaning, aging would become smelly and fishy.

After you brush it off, pat to dry. No fresh water on fish from this point.
Whatever you do, do not wash fish with fresh water after this.


No matter where you store fish, wrap it with paper towel. You want paper towel to absorb drips from the fish. The last thing you want to do is to let it soak in its drips. That would be the end of sashimi. If you store for several days, you should change paper towel everyday.

Some people don’t like to store fish in fridge because the circulated air will dry out the fish. It’s true that fish dries out faster than meats. But a little dry surface is good to preserve hygiene and moisture inside. I think it’s perfectly OK to wrap fish only with paper towel and keep it in the fridge. The circulated air dries only the skin.
You sure want to leave the skin on at this point no matter what. Big fish like tuna would need to be sliced into fillet bars to be kept. But after aging, sushi chef would scrape all the surfaces of the meat. You want to keep the fish as a whole as much as possible, with as few cuts as possible. We are talking about aging the fish. You want to leave the skin on for as long as you can. And with the skin on, and with the paper towel to absorb drips and avoid direct contact with circulated air, leaving fish in the fridge is no problem.

Curing fish with Pichitto!

Pichitto! is a liquid absorbing sheet. I just love this product. I just can’t thank enough those engineers who invented this. I think only Japanese are fish crazy enough to even think of creating this thing.

Pishitto! for semi-dried fish →

010_img02Pichitto! is a plastic sheet with special gel that absorbs liquid and edgy odors. The gel is made of glutinous starch and seaweed adhesive.
DO NOT cut the sheet when use it. Each sheet is like a plastic bag which holds the gel inside.
There’s no right side. Both sides of the sheet works at the touch with the meat surface.
You just need to wrap fish or meat with this sheet and let it sit in the fridge. The sheet has tiny holes, and by its osmotic pressure, the gel sucks in liquid and edgy odors from the fish. But it still leaves Umami components like glutamic acid in the fish, because these amino acids are big components and can not go through the holes in the sheet.


  • It takes out the excess liquid and edgy odors and condenses Umami (savor).
  • Overnight with Pichitto! wrap is usually enough to absorb liquid from surface. Pichitto! will stick to the surface and seal it. You can just leave it like that to store.
  • Usually you brine before Pichitto! and the fish will maintain its sashimi quality for at least a week. Of course you can cook in any style.

pichittoLiquid Absorbing Sheet
Regular 32 sheets: JPY2,268-

Shopping for Pichitto! →

Brining and Semi-drying definitely extends sashimi quality, giving enough time for the meat to age.

Here’s how I prepare it.

I always treat some fish with Pichitto! when I catch lots of fish that we can’t eat within the tasty period. The treatment extends sashimi quality period by at least 2 days.

Cold smoking is a great thing to do after Pichitto! It adds another dimension of flavor and helps to extend sashimi period too.

When sashimi period ends, what I think is the best thing to do is to sous vide the fish, whether it’s been smoked or not. Put small portions of fish meat in a plastic bag with olive oil, a bay leaf and some other herbs and spices if you want. Let it bathe in 60 ˚C water for 30 minutes. When done, rapid cooling with ice to bring it down to storing temperature. Then transfer from the plastic bag to a air-tight jar to store in fridge, and it will last a month. (Oil should be enough to cover all the meat in the jar. Add oil if necessary.)
The meat portions will make great appetizer or sandwich. Also it can be used as a seasoning for pasta or salad, like anchovy.

For some fish, freezing may work. But I’ve found breaded deep-fry is the only way that I can be happy with. So unless I want deep-fries, I would try everything to avoid freezing my catch. Please let me know if you know any other way!

I hope you find this article informative and helpful to you!

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  1. Tim

    You talk about brining. I know brining as soaking in salt water. Is this what you mean or can you explain what it is?

    • Totos

      Hi Tim.
      Yes, that’s exactly what I mean by brining. In the video, I did my brining with 10% salt water plus a little bit of sake.
      You posted this message. You should have felt something I wrote was confusing. Can you tell me what it is?
      Thank you very much for your interest.

  2. Tim

    Hi Totos
    I had not watched your video. I have now that clears everything up. Do you brine all your fish? I love your site and am looking forward to trying some slow pitch jigging here in Fremantle Western Australia, I know people do jig here. We also do a lot of trolling with lures and bait fishing for snappers etc. i love eating fish and think Japanese catch care is the best and your web site has some great info. Keep ip the great work and tight lines.

    • Totos

      OK Tim. I understand.
      Do I brine all my catch? No. But I could I suppose.
      Brining helps fish to release fishiness and hold moisture inside. Fishiness is in blood and in skin. When you fillet, fishiness lies on the surface. Contact with salt water seems to take it out. Fish meat also becomes plump and succulent when cooked after brining.
      But when you are doing sashimi, you want to brine with 3% salt water for 30 t0 60 min. 10% is for seasoning whole fish or fillet bars.
      You can just sprinkle salt on the fish and let it sit for 30 minutes. Then rinse off, pat dry quickly. This is another pretreatment of fish.

      Thank you very much for your encouragement too.

  3. Vlad vunich
    Vlad vunich07-01-2017

    Hi when you clean the blood line with brush in video it looked like you washed it under tap and could see how clean it was but then you said not to wash and brush only then wipe with paper towel but it would not look as clean as what you showed in video by just brush and towel would it?

    • Totos

      Hi Vlad.
      Maybe I was not clear.
      The fact is, fresh water extracts liquid from fish. What is extracted first is blood. What is extracted next is liquid the fish holds in the membrane and the cells. You want to remove the blood but not the liquid. Once you use fresh water to remove the blood, you want to avoid fresh water as much as possible. When you brush off the blood vessel, the meat is protected by the skin and the peritoneum, so the damage is minimum. Does that make sense?

  4. Hans

    I love all the advice on your site, but i think you have the science of osmosis wrong. When you have two solutions with different concentations of solutes (the flesh in a fish and water for example) water will travel towards the solution with a higher concentration of dissolved solutes. So brining is actually a way to remove water from a fish, presumably to make the flesh a bit firmer. On the opposite end of the spectrum, soaking the fish in fresh water would actually have water move into the fish, and into the cells, thus making the cells explode from excess internal pressure, which is why that makes the flesh mushy.

    • Totos

      Hi Hans.
      Thank you very much for your comment. As a matter of fact, you make perfect sense. Brined sashimi does have firmer texture. It is like the quality of Jamin Serrano or uncooked ham.
      I share the same idea as you. But maybe somewhere in my articles is misleading. I will look and check.

  5. Daniel

    Hi Totos,
    Since fresh water should be avoided because of osmotic pressure, isn’t it better to take guts out and brush off the major blood vessel still in the boat with sea water, after ike-jime and bleeding (I presume that when you do these tasks at home you use fresh water to clean the fish)?
    Also, what about scale? Amberjacks have very small scales, comparing to blue fish for example. Is really necessary to scale amberjacks and other fishes before aging? What happens if not? If it is necessary, again, would scale the fish still in the boat with saltwater improve umami?

    Regards, Daniel

    • Totos

      Hi Daniel.
      I understand what you are saying. But if you don’t soak the fish in the fresh water, you don’t have to worry about the osmotic pressure. You can rinse fish with the running water as long as it has skin on and peritoneum on, and the water doesn’t directly touch the meat you are eating. You can do everything from gutting, cleaning to filetting with fresh water in the kitchen, like every sushi chef does.
      What every fishery experts say in Japan is to make as few cuts as possible if you keep the fish. So really Ike-Jime 3 steps are all you need to do on the boat. Instant close. Spinal cord. Bleeding. That’s it. I don’t scale on the boat. I don’t cut open the belly on the boat.
      As long as the fish is cooled, even the guts don’t go bad so quickly. I clean the fish the next day usually. I scale it (some people keep scales for aging). Remove guts and gills. Scrape off the major blood vessel under the spine. Cut off head and tail if space is limited. Then wrap for the drips and store.

      But I have never seen a study to prove that less cuts make better aging. You can do what you believe is right. But I trust the Japanese fishery’s tradition on this. Fishermen, buyers, sushi chefs, no one wants the fish to be scaled or gutted on the boat.

      • Daniel

        Hi Totos,
        I understand and agree with all your points. Also I am a fan of Japanese culture; thanks to you we are all learning a lot; thank you very much.
        I also agree that less cuts are better, even if we don’t have any study that justify that. But think with me about this point, the numbers of fish cuts are the same, we all cut the belly and remove guts and gills before aging (I am now also brushing the blood following your advices). What we are talking about is when to do that, at boat or at home, with a difference of juts a couple of hours. See that, if we are not tired, we do that the same night, or, in the worst case, just some hours later, the next day. But both just before aging, almost no difference in time, and the total number of cuts, at the end, remains the same.
        I was just speculating that sushi chefs don’t want the fish to be gutted on the boat because they prefer to do that by their own. They might be afraid that we might possible do it improperly and cut some other meat parts or even blow up the guts and spread the bile or even because they might be interested in using some possible fish eggs we might discard.
        As far as I see, the advantage of doing those procedures at home is that we have more boat fishing time, and the advantage to that at boat is that we don’t mess the kitchen, we can clean the fish with salt water, and less bad smell at home (belly guts always have same bad smell and debrits, even if properly cooled at boat).

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