Sushi Ingredients | Sushiblog－Sushiuniversity

About anago, there are two way to make sushi, “skin-up ” and “skin-down”.

Do you know the difference?

The naval (actually the anus) in the middle of the body serves as the border separating the head part (top) and tail part (bottom) of the eel. The fat is distributed better on the top. People used to say that since the bottom moves more it is more tasty, but is this really true?

It’s also often said, “the top should be served skin-up and the bottom should be served skin-down.”

Skin-up means that the skin side is on top and the meaty side is on the rice.

Skin-down means that the meaty side is facing up and the skin side is on the rice.

Conger eel easily melts apart when it is boiled and broth enters the part where it separates, so the appearance is not as appealing. But unless the crack is extremely obvious, both the top and bottom of the conger eel is often prepared skin-down in sushi.

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Revision date: August 27, 2018

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The migrating route of Inshore Pacific bluefin tuna and fishing place!

An illustration of Kuro maguro main prodution area — This is the migration route of Kuro maguro (bluefin tuna).

Tuna caught in the coastal regions of the Japan Sea is notable as the best bluefin tuna in January. Iki, a small island in Kyushu area is one of the famous ports for tuna.

In February and March, the tuna auction market becomes slack due to rough weather. Just a few tunas from Nachikatsuura where is also the famous port for tuna are on the market.

In March and April, tunas become thin because their eggs need many nutrients.

In May, large tuna is seldom seen in the Tsukiji Fish Market. Even if there is, its body is really thin. “Kinkaimono” which means a shore-fish is generally considered as high-class tuna, but in this season, imported tuna is useful instead.

It is said that Pacific Bluefin tunas spawn around Japanese waters between Taiwan and Okinawa in April and May. And then, they go up to fertile, north sea along the eastern coast of Japan.

In June, “Chubo” which is young and small tuna is taken hugely off the coast of the Sea of Japan. The school of Chubo begin moving northward in this season.

In July and August, tunas can be seen occasionally but their bodies are still thin. Instead, Boston Tuna which is caught in the Atlantic Ocean and nicknamed “Jumbo” is on the market. Its fresh is softer than “Kinkaimono” and it doesn’t have medium-fatty part which “Kinkaimono” has.

In September, Boston Tunas are at their best with plenty of fat on them. The best season of Boston Tuna is limited and ends in October. But fortunately, Japanese tunas come into season.

The school of tunas split up into two groups, the one takes Pacific Ocean route and another takes the Japan Sea route and both of them move northward along the Japanese Islands. Some of them reach the Tsugaru Strait where and the season of Tuna begins from September to next January. Oma town and Toi town is famous nationwide for its catch of tuna from the Tsugaru Strait. The flavor of tuna in September is still weak but it becomes stronger in October. In November, feed of tunas such as Pacific saury or Japanese common squid with plenty of fat increase and flavor of tuna also gets stronger. In December, the peak season comes around.

A catch of tuna falls off in January and it enters the final season. The temperature of sea water gets cold and feed of tuna, squids decrease and the fishing season in this area ends.

Related contents: TYPES OF TUNA

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Revision date: August 20, 2018

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Why can’t Sanma (pacific saury) be caught?

On the Pacific Ocean side of Japan there is a three-way deadlock between sardines, mackerel and Pacific saury. There is a theory that the species take turns with increasing and decreasing populations. In recent years there has been an increase in sardines and, in turn, there has been a decline in Pacific saury.

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Revision date: July 30, 2018

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What is the difference between maturing and rotting?

When fish die, stopping the supply of ATP (Adenosine Triphosphate), the source of muscle energy, the muscle fibers gradually harden. As time passes, it gently dissolves and the ATP breaks down, changing into umami components due to self-digestion.

ATP is broken down as follows, but in living fish, only the reaction up to AMP occurs. Once broken down to AMP, it is regenerated as ATP.

ATP→Adenosine diphosphate (ADP)→Adenosine monophosphate (AMP)→inosinic acid (IMP)→hypoxanthine riboside (HxR)→Hypoxanthine (Hx)

In fish after death, inosine monophosphate (IMP) is produced from AMP by an enzyme called adenosine deaminase (ADA). This is called maturing. Inosine monophosphate is not found in cells immediately after death. Maturation is required for the production of inosine monophosphate. If it goes further, it will go bad and HxR (inosine) and Hx (hypoxanthine) will be produced.

The umami created by self-digestion of ATP is “maturing (Jukusei)” and the process after that is “rotting.”

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Revision date: March 17, 2025

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What are Meji, Chubou and Maguro?

The bluefin tuna goes by different names in Japanese depending on its age. It starts out as “Meji (メジ or メジマグロ),” grows into “Chubou (中坊)” and finally is called Maguro (once it’s 50 kg or more).

Meji is less than 1 year old and weighs around 20 kg.

Chubou is an old word for relatively low-class Buddhist priests who were treated as errand boys. I guess it was meant to imply that these boys were even weaker than tuna. At this stage, the fish are between 2-5 years old and weigh about 40kg.

Anything larger than that is called Maguro. The biggest is 3m long and 600kg or more. Especially large tuna is called Shibi. “Shibi” comes from the Japanese characters for “4-days”, which is how long the fish takes to mature.

Most Meji and Chubou are caught from May until the beginning of autumn when Maguro is thin and tasty.

Meji has a unique scent and taste that sets it apart from full-grown tuna. The color is similar to the skipjack rather than bluefin. On the other hand, Chubou has a lighter color and it isn’t as rich, but the flavor is young, refreshing tuna. That is why Meji is considered to be a completely separate sushi topping and Chubou is presented to be a type of tuna.

Related contents: TYPES OF TUNA

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Revision date: May 4, 2021

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Are the most prestigious sushi restaurants all in Tokyo?

It is called Edomae sushi, so the most appropriate place to eat it is Tokyo, formerly known as Edo. The skills of chefs raised in this long history of sushi. The best fishery products in Japan — no, in the world, are all found at Toyosu Market. There is no question that combined with the veteran sushi experts, Tokyo is the battleground for sushi restaurants and where you’ll find the most prestigious locations like Ginza, Nishi azabu etc.

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Revision date: July 16, 2019

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People all over the world tend to be forced to eat sushi with fake or substitute fish!?

Seafood product buyers tend to believe that the products they are purchasing are as described by the sellers. But, that isn’t always the case. Seafood products are sometimes intentionally labeled incorrectly for profit.

This is seafood fraud. Fraudulent actions like this threaten the safety of the food. From the FDA’s “Report on Seafood Fraud”

70% of seafood consumed in the US is eaten at restaurants. The products served at restaurants are generally lower quality than those sold in retail outlets and the sushi is especially appalling. Unless visiting a top-class sushi restaurant (where the prices are, of course, high), you can usually expect to be served the worst of the worst.

There isn’t much a consumer can do about this, but at the very least you can educate yourself on types of fish that are often substituted. If you were to order White Tuna or Red Snapper, you would very likely be served something else. Any shrimp ordered was probably farmed.

There are no laws regulating “Fresh” or “Organic” labels so don’t be fooled by these. In the same way, be suspicious when you see word combinations like “Great Sushi” or “Great Sashimi.” There is no such thing as “Great” in this sense.
By Larry Olmsted, a print columnist for two of America’s three national newspapers, Investor’s Business Daily and USAToday

*FDA・・・Food and Drug Administration

Can’t-miss Tokyo sushi toppings (Meji Maguro)

Meji Maguro (AKA: Meji) caught in fixed net fishing is one type of sushi topping that you really should try. Meji is the larval fish of Pacific bluefin tuna, made and served at expensive restaurants, but not usually available as Edo-style sushi. Its fat is lighter and it doesn’t have the impact that fatty tuna has. Efforts are put into seasoning to avoid this. Using a pinch of ginger, Japanese basil or onion between the topping and rice, along with the wasabi, really brings out the fresh flavor of the young fish as well as the sweetness of this fatty part.

Related contents: TYPES OF TUNA

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Revision date: March 26, 2018

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Why is freshly-caught fish allowed to age?

The most delicious time to eat fish differs depending on if it is served as sashimi, as sushi, or boiled. Fresh does not necessarily mean delicious. For example, Japanese Amberjack should be used in sashimi 3-5 days after being caught, in sushi a week after being caught and it can be used in a stew or boiled once it turns black around the edges. This is because the inosine acid, which is responsible for the umami taste, increases after rigor mortis ends and understanding the timing of the peak in flavor is up to the skill of the sushi chef.

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Revision date: March 12, 2018

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Why does the bill more when ordering sashimi at a prestigious restaurant?

Thicker cuts of fish are used for sashimi than for sushi. Depending on the restaurant, the equivalent of three pieces of sushi may be used in one cut of sashimi. In other words, two pieces of sashimi is the same as six pieces of sushi. At a restaurant where one piece of medium fatty tuna sushi is priced at JPY 1000, simple arithmetic prices medium fatty tuna sashimi at JPY 6000. Just a small order of assorted sashimi often costs more than JPY 10,000. Be careful.

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Revision date: March 5, 2018

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Why are two pieces of nigiri sushi made at once?

Have you ordered Nigiri-sushi and been served two pieces on one plate?

There are multiple theories as to the reason for this, but the most likely one is as follows.

The reason sushi is served in sets of two pieces is that this practice is left over from long ago (the Edo period), when pieces of sushi were made large, like onigiri, and difficult to eat. At some point (it’s unclear when), these were just cut in half, making two pieces that led to what we see today (there are multiple theories about when this happened).

However nowadays, if you were to eat two pieces of each topping, you won’t be able to enjoy as many different kinds, so customers sitting at the counter are served only one piece at a time. So then why do other restaurants continue to prepare two pieces at once? This may be in order to improve the efficiency of the sushi chef’s work. Also, regular customers may see toppings others are ordering and ask for the same one. This helps reduce the workload of the sushi chef.

But there are also some toppings that are better to eat in pairs.

For example, conger eel tastes completely different when one piece is eaten with salt and the other seasoned with sweet sauce. Serving the part of the eel closer to the head skin-up and the part closer to the tail belly-up also offers different textures; skin-up offers a smooth texture while belly-up offers a fluffy texture. In addition, the head and tail simply taste differently. Since the back and belly of fish like bonito and mackerel have different fat content, it can be better to order two pieces at a time in order to fully experience each of the individual qualities of the fish.

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Revision date: March 27, 2023

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Why don’t I notice the fishy smell in sushi restaurants?

Many overseas visitors who aren’t used to eating fish have an aversion to fishy smells. This is actually the smell of a substance called trimethylamine and is generated by the breakdown of the umami component called trimethylamine oxide found in large amounts in fish by bacterial growth. The smell also gets stronger with the generation of ammonia as more time passes.

Bacterial growth can be controlled with refrigeration so toppings at sushi restaurants are kept cold. Trimethylamine is an alkaline, so smells can be eliminated by washing with vinegar, which is acidic. It is also possible to kill bacteria on the surface of the fish by soaking it in vinegar, reducing the number of bacteria. Basically, sushi restaurants are constantly taking measures to prevent bacterial growth and avoid fishy smells.

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Revision date: February 19, 2018

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Why is sushi with tuna topping so expensive?

A purchase of raw tuna costs at least JPY 30,000 per kilogram. Furthermore, good tuna is judged not only by taste, but appearance is also highly regarded.

The surface is gradually oxidized by letting it sleep (mature) and the sushi chef makes sure that parts are cut of as they change color, when the timing is perfect for both the taste and appearance. In other words, skin is taken from the freshly purchased tuna, the meat of the fish darkened by blood (the blackened area that can’t be used as sushi toppings) is removed, the parts that have changed color are shaved off and then only the remaining, best parts used as toppings are left.

This is why the price is high.

Related contents: TYPES OF TUNA

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Revision date: February 5, 2018

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Tuna was not a premium fish during the Edo period!

During the Edo period, tuna was not highly valued as a sushi topping and it was referred to as “Gezakana” meaning that it was inferior to normal fish. The reason was the big size of the tuna. At this time there was no ice, so tuna had to be salted. It was cut into blocks, salt was spread all over and in it, and that was it. At Uogashi (the market prior to Tsukiji) it was treated at shops that specialized in salting fish. The dark, discolored, salty chunks of flesh really were nothing but “Gezakana*”.

*Gezakana －Relatively low-cost sushi ingredients, such as gizzard shad and horse mackerel. Bluefin tuna used to be also called gezakana in the Edo period, for losing its freshness easily.

Related contents: TYPES OF TUNA

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Revision date: December 30, 2017

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What makes a good sushi chef?

The balance between Shari (vinegar rice) and the topping is important in sushi. No matter how good the topping, the sushi won’t be good if the Shari isn’t right for it. More restaurants have been using red vinegar lately, but even if you use a Shari with a strong taste like red vinegar, the balance will be destroyed if the topping has a weaker flavor. Seasoning that goes well with various toppings that doesn’t stand out too much is ideal.

It works the other way, too. If the Shari is too weak, the sushi won’t be delicious no matter how good the topping. Even if the topping is not premium quality, if the Shari is matched perfectly, the sushi will be perfect. In other words, a good sushi chef is someone who can make sushi with perfectly matching toppings and Shari.

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Revision date: December 18, 2017

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