Edomaesushi | Sushiblog－Sushiuniversity

What is traditional Ikejime?

a photo of Ikejime Madai — In order to fully drain the blood from the red seabream, the spinal cord at the base of the tail is also cut off.

Articles related to Sushi are now filled with jargon such as Shinkeijime, Chinuki, Noujime, Ikekoshi, and Korijime. That much confirms the fact that opportunities to eat fish are increasing all over the world. And it has also become a common occurrence to find articles written by people who have heard Ikejime in bits and pieces. According to what we have heard, Ikejime processing is one of the reasons why red seabream from Akashi, which is said to be the best in Japan, is so tasty, and the technology has been around since the Edo period (1603-1868).

The Ikejime procedure consists of four parts or some of them, and the point of Ikejime is to kill the fish in a relaxed state.

The first step is a brain-dead the fish by stabbing it in the head with a sharp object. This process is called Noujime (Nou means brain and jime means kill).

After the fish is out of the water and before it gets out of control, it is stabbed in the head with a hook called a Tegaki (手鉤). If the brain is not destroyed by one blow, the fish will struggle. When this happens, a large amount of ATP, which is the source of umami, is consumed. As a point of caution, the right side of the head is stabbed so that the puncture wound is not on the upper side, as the fish will be handled later in the distribution process with the belly facing forward and the head facing to the left.

Next, use a knife to quickly kill the live fish.

Place the fish with its head facing left, open the gill cover, and cut a spinal cord below the lateral line that is visible on the fish’s body. Since bones have hard parts, move the cutting edge slightly to the left and right if it is difficult to cut. If you don’t cut it completely, you have not killed the fish, and the blood will not drain well. To drain the blood sufficiently, the spinal cord at the base of the tail is also cut off. Place the fish’s head to the right and cut the front part of the tail so that the spinal cord is visible. At this point, the knife should be placed at a right angle to the spinal cord so that the cut surface is not at an angle.

The next step is to remove the nerves and delay rigor mortis. This process is called Shinkeijime (Shinkei means nerve).

Shinkeijime is a technique to delay rigor mortis in fish. A wire is inserted into a small hole in the upper part of the spinal cord. When the wire hits the nerve, the fish will act violently, so hold it down. The nerve hole tapers from the head side to the tail, so when stabbing in from the tail side, make sure to insert the wire securely first, so that the wire does not pierce through the nerve hole and pierce the body. Once you have securely inserted the wire, repeatedly pull out and insert the wire to completely destroy the nerve in the hole. When the nerve is destroyed, the body color quickly changes to white. The destroyed nerve appears as a white, sludgy fluid.

Any wire can be used for this purpose as long as it is straight, but a piano wire that does not bend easily can be used many times. The diameter of the nerve hole differs depending on the fish. Use a thick wire for Tai and Suzuki, which have large nerve holes, and a thin wire for Aji and Anago, which have small nerve holes. Several types between 0.8mm and 1.5mm should be enough. As you get used to it, you will be able to stick the wire in without visually seeing the nerve hole. If you remove a few scales from the upper part in front of the tail, insert the wire along the spinal cord, probe the nerve hole, pierce it, and destroy it, you can remove the nerve without making any cuts on the fish’s body. The same applies to the head side. The nerve hole is probed and pierced from the head side, but the key is to keep the head and body straight so that the nerve hole is not misaligned by the spinal cord severed behind the gills. In any case, it takes experience and familiarity to pierce the nerve hole without seeing it.

The final step is to perfectly remove the blood from the fish’s body. In Japanese, it is called Chinuki (Chi means blood and nuki means remove).

The blood is removed by cutting the spinal cord and immersing the fish’s body in seawater. At this time, running water is more reliable to remove blood. In the case of stored water, leave it for a while and then replace it with other stored water. If the water does not turn red with blood, the fish has already been drained. Blood has a tendency to clot, so it is important to wash off any blood that has clotted on the gills or other parts of the body. The body temperature of the fish is raised by the Ikejime process and by human hands. Since the fish were originally in the sea, which has a lower temperature range than that of the ground, the higher temperature increases the speed of deterioration, so the fish is soaked in ice water to lower the temperature of the fish’s body. If the fish is soaked too long, its body surface will turn white, so remove it from the water when it cools down.

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Revision date: August 18, 2023

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Here’s a Michelin sushi restaurant where photography is not allowed!

a photo of Kuromutsu nigiri sushi — Kuromutsu were disturbers a long time ago when we were fishing Splendid alfonsino (Kinmedai). And they were not really liked by Edo people who don’t really like oily taste.

In this age of social networking, there is a certain discomfort in not being able to take pictures of your food. But sushi restaurants don’t want people to write bad things about them, and most of all, other customers may feel uncomfortable about the sound of the shutter. Especially for regular customers, this behavior is not funny. On the other hand, it is human nature to want to show off on social media or record your visit to a restaurant where reservations are hard to come by. It is the policy of the restaurant, so if you cannot follow it, just don’t go there.

Therefore, we investigated Michelin sushi restaurants where photography is not allowed.

Of the 30 sushi restaurants that received stars in the Michelin Guide Tokyo 2023, the following five are among those where photography is prohibited. Of these, Sawada in Ginza is the only one that has not been photographed, probably because it has been prohibited ever since it moved from Nakano to Ginza. The other four have been banned at one point or another. This means that at the remaining 25 establishments, Oyakata (Sushi master) is still allowed to take pictures, albeit reluctantly. However, the sound of the shutter is not very pleasant, so care must be taken when taking pictures.

Sushi Yoshitake

Sawada

Sushi Kanesaka

Takagaki-no-sushi

Sushi kuwano

Next up is a sushi restaurant previously awarded a star in the Schlumberger Guide Tokyo where photography is not allowed. Sushi Arai will open a new restaurant on the second floor of the same building in spring 2021, in addition to its previous location on the basement floor. Photography is not permitted at the new restaurant. Sukiyabashi Jiro will be replaced by the eldest son, and in my opinion, it will become OK (it is still NG). The reason is that the customers will be replaced by new ones.

Sukiyabashi jiro

Sushi Arai

In summary, if the restaurant offers the Omakase course, which is strongly recommended, we would like to be allowed to take pictures. The reason is that we are eating at the convenience of the restaurant, so “we are cooperating, right? Let me at least take a picture”. As one example, Sushi Saito, which has been awarded three Michelin stars for 10 consecutive years, has a section that considers photography as part of its service. On the other hand, if you eat at Okonomi, the sushi chef and the restaurant are both forced to work hard, and you are told to “Eat quickly” before taking any pictures. For your information.

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Revision date: July 22, 2023

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What are Fish paste products?

Essentially, no fish cannot be processed into fish paste products using current food processing technology. However, it is important to have a stable supply of high-catch fish species, which are inexpensive, and whose meat is suitable for fish paste products. High-catch species such as sardine and Alaska pollack are the main raw material for mass-produced fish paste products. However, many of the fish paste products that are considered local specialties in Japan are originally produced using locally caught fish. Among fish paste products, fish species other than the most prolific are used when the flavor of the product varies depending on the fish used.

Now that you understand more, let’s continue with the explanation using Kamaboko (蒲鉾), the most widely used fish paste product, as an example. The preferred fish to be used as the raw materials for Kamaboko have strong Ashi, good Suwari and doesn’t Modori easily.

Ashi refers to the moderate resilience that Kamaboko has, with a crisp and crunchy texture, proving that it is a good product. In other words, strong Ashi means that the fish has adequate firmness. Types of fish with strong Ashi include Flyingfish, Japanese aulopus, Brushtooth lizardfish, Bartail flathead, Red seabream, Golden threadfin-bream, Silver croaker, Honnibe croaker, Grub fish, Spiny goby, Indo-Pacific blue marlin, Globefish and others. Generally, Shiromi fish are considered to be strong and Akami fish are considered to be weak, while freshwater fish and shrimp are considered to be weak for the most part.

Suwari refers to the ease of surimi hardening and depends not only on the difference in type of fish, but differences also occur due to temperature and pH of the surimi, freshness of the raw fish material and how the fish was killed. In other words, poor Suwari means that the fish doesn’t firm up easily. Fish well-known for having good Suwari start with Indo-Pacific blue marlin and also include Honnibe croaker, Flying fish, Brushtooth lizardfish, Grub fish, Red seabream, etc. Fish known to have poor Suwari included crucian carp, bonito monkfish, sardines, etc. Generally, fish that live in coldwater regions have better Suwari while fish that live in warm waters and freshwater fish have poor Suwari.

Modori or Hi-modori refers to the phenomenon of weakened elasticity when fish that were hardened through the Suwari process has been further heated. Modori depends on the type, freshness and season the raw material fish was caught. Fish that don’t succumb to Modori easily include Grub fish, Needlefish, Indo-Pacific blue marlin, Starspotted smooth-hound, Flathead gray mullet, Horse mackerel, etc. Fish known to succumb to Modori easily include sardine, leatherjacket, Honnibe croaker, Chub mackerel, Crucian carps, Japanese Spanish mackerel, etc. Surimi color is reflected in the finished product, so Shiromi fish with a white finish is generally preferred over Akami fish, which results in a darker finish. However, it is possible to create a white finish, even using Akami fish, with some extra work.

Because the unique flavor of the raw fish is lost during the Surimi production process, it is common to season the fish afterward, but some specialty products are produced in such a way that the flavor of the raw fish is not lost.

Until World War II, the production of fish paste products was not organized for mass production, and many factories had only a few craftsmen at most. Only locally caught fish were used as ingredients. Since there were no refrigeration facilities, the factories had to be closed during the summer months, when it was difficult to maintain quality.

After the war, when the bottom trawling fishery in the East China Sea started, raw fish such as Silver croaker, Yellow croaker, Large yellow croaker, Eellowback sea-bream, Nemipteridae, and Largehead hairtail came to be supplied cheaply and stably. Advances in cold storage technology and distribution networks have also made it possible to mechanize the production process and mass produce products.

As a result, the production of fish paste products continued to increase in both quality and quantity, and the demand could no longer be met by inshore raw fish alone. At this time, frozen surimi from Alaska pollack appeared on the market.

Frozen surimi is a raw material made by adding sugars such as sucrose and sorbitol, which prevent protein denaturation, and polyphosphate to surimi and then freezing and storing it. The basic technology for frozen surimi was developed at the Hokkaido Fisheries Experiment Station in 1960.

Frozen surimi can be classified into three categories: unsalted surimi, which has little protein denaturation during freezing; salted surimi, which can be commercialized with high ash content; and ground surimi, which is processed at a factory from raw fish.

The quality standards for the commercialized surimi are set by the National Frozen Fish Meat Association, and there are several grades of surimi in the Alaska pollack. Most of the frozen surimi produced are made from Alaska pollack, but due to a decrease in Alaska pollack production, Red seabream and Nemipteridae caught off the coast of Hong Kong have also been used as surimi raw materials.

Types of Fish paste products

Chikuwa

Chikuwa is Surimi wrapped around a bamboo stick and heated. The baked chikuwa is called yaki-chikuwa, and the steamed chikuwa is called shiro-tikuwa. Toyohashi-Chikuwa from Toyohashi City, Aichi Prefecture, is especially famous. It is characterized by the fact that both ends are white and only the middle area is browned.

Date-maki

Date-maki is made by adding eggs and sugar to Surimi, rubbing to a foamy consistency, and then baking. Good quality is considered to be made with sharks as the raw material fish. Date-maki is known throughout Japan as a New Year’s product.

Yaki-kamaboko

Among the many types of kamaboko, yaki-kamaboko is the most common type of kamaboko in Japan. Historically, this method is the oldest.

Yaki-ita in the Kansai region is made from Daggertooth pike conger, Synodontidae, and Sciaenidae. In order to preserve the flavor of the ingredients, the process of soaking in water is shortened, and the surimi is steamed and hardened once before the surface is seared and browned.

Hanpen

Hanpen is made by adding yams to Surimi, making it foamy, and steaming it. It is characterized by the lack of ashi and a fluffy marshmallow-like texture. It is a fish paste product unique to the Kanto region, and the best fish paste products are those that use sharks as ingredients. It is one of the oldest fish paste products.

Kanikama

Kanikama is a fish paste product that has the texture, shape, color, and flavor of crab, just like crab meat. The raw material is not crab but fish surimi. The main ingredient is Alaska pollack, a white fish that has no peculiarities or odor. Other surimi such as golden threadfin-bream and largscaled saury are also used.

Mushi-kamaboko

Mushi-kamaboko was already being produced around the end of the Edo period. It is most commonly found in the Kanto area, with Odawara-kamaboko in Odawara City, Kanagawa Prefecture, being the most famous.

Odawara-kamaboko is mainly made from Sciaenidae and soaked in mineral-rich groundwater to produce a white, ashi-rich product. Odawara-kamaboko is also characterized by the abundance of Itatsuki-kamaboko.

Naruto-maki

Naruto-maki is made by coating the inside of white surimi with red-colored surimi, rolling it up in a bamboo screen, and steaming it. It is called this because the spiral pattern on the cross section is associated with the whirlpools of Naruto. It is used as a garnish for noodles and chirashi-sushi.

Sasa-kamaboko

Sasa-kamaboko is a type of yaki-kamabo. Sasa-kamaboko from Sendai City, Miyagi Prefecture, uses a mixture of Bastard halibut, Broadbanded thornyhead, and Nemipteridae as ingredients, shaped into a leaf shape, and grilled over charcoal.

Satsumaage

Satsumaage is a generic name for deep-fried surimi. The best products are made from Sciaenidae and Synodontidae. Some products from Kagoshima and Okinawa are made with brown sugar, which gives them a very sweet taste.

Hamo-ita

Hamo-ita is made from only daggertooth pike conger, steamed once, and then carefully baked. It is a specialty of Osaka.

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Revision date: June 29, 2023

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What is the difference between fermentation, putrefaction, and maturing?

In academic terms, “fermentation” is a reaction that uses no oxygen to break down carbohydrates to obtain energy. On the other hand, the reaction that uses oxygen to break down organic matter to obtain energy is called “respiration”.

In more familiar terms, microorganisms such as lactic acid bacteria, koji-mold, and yeast break down organic compounds such as carbohydrates and proteins to produce a variety of by-products to obtain energy in their own life activities. Among these, “fermentation” is a phenomenon in which beneficial substances are produced for humans, while “putrefaction” is a phenomenon in which harmful substances are produced for humans. Food spoilage can be detected by the five senses, such as smell, appearance, and taste.

What is the difference between fermentation and maturing?

While “fermentation” and “putrefaction” are caused by microorganisms, “maturing” is a process in which the food itself is transformed by enzymes and other substances to produce something beneficial to humans. Or, “maturing” is the process of improving the flavor and quality of food by allowing it to rest under controlled temperature and humidity after fermentation is complete. Maturing is said to be beneficial to humans because it changes the texture and taste of the fish, making it tastier.

In case you are wondering, “enzyme” is mainly composed of protein, which promotes chemical reactions such as digestion, absorption, and metabolism that are necessary for all living things, including humans, animals, and plants, to survive. It is said that there are approximately 5,000 enzymes in our body, but each enzyme is a specialist that performs only one function and is largely divided into “Digestive enzymes” and “Metabolic enzymes.

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Revision date: May 25, 2023

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What is Blackfin Seabass (Hirasuzuki) sushi?

a photo of Hirasuzuki — The main habitat of blackfin seabass (Hirasuzuki) will be a rough ocean facing the open sea from autumn to spring, and it will not catch a calm day and catch when it becomes rough weather.

What is Blackfin Seabass (Hirasuzuki)?

Blackfin Seabass (Hirasuzuki) prefer warmer waters and are distributed south of the Boso Peninsula on the Pacific Ocean side, and south of Hokuriku on the Sea of Japan side, as well as in the southern part of the Korean Peninsula. Juveniles and young fish may be found near estuaries that connect to the open ocean, but as they mature, they move to areas of higher salinity and are not found in the brackish waters near estuaries.

It is very similar to the Japanese sea bass (Suzuki) only in the same genus, but is taller and more strongly laterally flattened than the Japanese sea bass. A large Blackfin Seabass exceeds 1 meter. The scientific name is Lateolabrax latus Katayama, 1957.

What does Blackfin Seabass (Hirasuzuki) sushi taste like?

a photo of Blackfin Seabass (Hirasuzuki) — This may be a bit of a challenging statement, but there must be very few sushi chefs using Blackfin Seabass (Hirasuzuki).

Blackfin Seabass is in season during the cold season, the opposite of Japanese sea bass. Unlike Japanese sea bass, blackfin seabass has a bright red, clear white flesh with no black streaks in the flesh. This makes it look better than Japanese sea bass when served as nigiri or sashimi. Another reason for the high price is that there are few arrivals at Toyosu Market. It used to fetch more than blackthroat seaperch (Nodoguro).

Blackfin Seabass are firm and fatty. Unlike Japanese sea bass, which lives in brackish water, Blackfin Seabass does not have a muddy smell, perhaps because it lives on rough reefs connected to the open sea. It is often described as having a taste similar to Isaki or Tai, for example, with a refined flavor and a sweet aftertaste. It is a top-quality fish that can replace Hirame, which is a representative winter shiromi.

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Revision date: May 1, 2023

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What is the difference between Shiso and Ooba?

a photo of Ooba — Ooba (Aojiso) is the name for only the leafy part of the shiso plant, the green perilla.

Actually, Shiso (紫蘇) and Ooba (大葉) are the same things.

a photo of Red perilla — Akajiso (red perilla) is a perilla with reddish purple leaves.

Shiso (perilla leaf) has green perilla (青紫蘇) with green leaves and red perilla (赤紫蘇) with reddish-purple leaves. Shiso is originally reddish purple in color, and green perilla is a variant of red perilla. The red color of red perilla is due to the pigment shisonin, a type of anthocyanin.

What is Shiso?

Shiso originates from southern China to Myanmar. The shiso is an aromatic Japanese herb and has been used as a condiment in tempura and other Japanese dishes for centuries. Shortly sprouted seeds are called Mejiso (芽紫蘇). The young shoots of green perilla are Aome (青芽), and the young shoots of red perilla are Murame (紫芽).

And Hanajiso (花紫蘇), where about 30% of the shiso flowers are about to bloom. Hojiso (穂紫蘇) is harvested while the fruit is immature. These are also used as garnishes and condiments for sashimi and other dishes.

Why is Shiso called Ooba?

There are two theories. One is to distinguish it from Mejisho, which was used as Tsuma for Sashimi. The young shoots of shiso are Mejisho and the leaves of shiso are Ooba. The other is Ooba, which was adopted as the trade name for the bundles of green perilla leaves that were sold. Since neither of these names is well known to the general consumers, there is no understanding that green perilla and Ooba are the same things.

The many benefits of Shiso

Shiso has one of the highest levels of β-carotene among vegetables. β-carotene is an antioxidant that boosts immunity and protects the body from active oxygen species that cause cancer and atherosclerosis. Shiso is also rich in alpha-linolenic acid. It is converted into DHA and EPA in the body and is believed to prevent aging.

Shiso is rich in iron. Since anemia requires supplementation of iron deficiency, shiso leaves, which are rich in iron, are good food for preventing anemia. It also contains high amounts of calcium, which helps iron absorption.

Shiso contains high levels of potassium, a mineral that helps the body eliminate excess sodium in the urine. By controlling water metabolism in the body, it is expected to reduce swelling.

Perillaldehyde, the aromatic component of green perilla and red perilla, stimulates the secretion of gastric juice, increases appetite, and stimulates gastrointestinal function. red perilla is also used in Chinese herbal medicine to improve gastrointestinal symptoms. It also has strong antiseptic and antibacterial properties. It is often used as a condiment for sashimi tsuma and other dishes because of this potential antimicrobial and sterilizing action, and it is also believed to have some antiseptic properties.

Rosmarinic acid, a type of polyphenol contained in Shiso, is believed to suppress the generation of the active oxygen with its high antioxidant power, making it less likely to cause allergic symptoms. Taking it into the body on a daily basis is expected not only to suppress the aggravation of inflammation but also to make the body less prone to inflammation.

The β-carotene in shiso prevents skin from oxidizing and aging. Calcium, which is abundant in shiso leaves, helps to connect skin cells to each other. It is also rich in vitamin C, which is believed to be effective in whitening the skin.

a photo of Squid nigiri — The common taste of squid is sweetness. However, the taste is not very rich. Therefore, Nori or other ingredients are placed between the sushi rice and the sushi topping, because Nori has a unique umami taste due to amino acids, such as glutamic acid.

As a side note, Ooba is often placed between the shari and squid at conveyor-belt sushi restaurants. This is to mask the fishy smell of the squid with the smell of the Ooba.

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Revision date: April 11, 2023

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What is Blue rainbow trout (Cobalt masu)?

a photo of Blue rainbow trout — Blue rainbow trout are an angler’s dream.

The Japanese name for the blue rainbow trout is Cobalt masu, derived from its blue body color. Blue rainbow trout is a mutation in the hatchery production of rainbow trout. This fish lacks the middle lobe of the pituitary gland. This resulted in blue body color. This rare genetic glitch has occurred only in rainbow and brown trout. It is said that one blue rainbow trout is born for every ten of thousand rainbow trout. This trait is inherited recessively. It does not reproduce and is susceptible to disease. Therefore, although it has a beautiful body color, it is difficult to produce in large numbers.

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Revision date: April 8, 2023

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What is Albino rainbow trout?

a photo of Albino rainbow trout — Other Albino fish have a white body color, but the Rainbow trout has a yellow body color.

There is a Rainbow trout with yellow body color.

This is the Albino rainbow trout.

The Albino has no pigmentation. Other Albino fish have a white body color, but the Rainbow trout has a yellow body color. Since its first discovery in 1956 at the Fisheries Experiment Station in Nagano Prefecture, Japan, experiments conducted by crossbreeding Albino with other Albino or Albino with ordinary Rainbow trout have shown that it is genetically dominant. Pure descendants of the Albino are now being produced in aquaculture farms throughout Japan.

Albino is rarely found in the normal production of Rainbow trout in aquaculture farms. Albino is a mutation of the Rainbow trout that lacks tyrosinase (An enzyme that breaks down tyrosine, a type of amino acid, to produce melanin). This prevents the production of melanin, a black pigment, and causes the trout to turn yellow. The yellowish coloration is thought to be due to the other pigments that remain after the melanin-black pigment is gone.

Normal Albino is genetically recessive, so if both parents are not Albino, their offspring will not be Albino. However, Albino rainbow trout is dominant, so if either male or female parent is an Albino, their offspring will be born as an Albino.

Neither the albino rainbow trout nor the blue rainbow trout is a protective color, so if it were to occur in nature, it would have little chance of surviving due to bird damage.

Albino rainbow trout has little edible value but is released for recreational fishing because of its scarcity. In fish farms, it is sometimes used as a visible indicator of growth. There may be some differences in taste, smell, and texture, but these are within the range of individual differences. And Sushi chefs do not use Albino rainbow trout for sushi.

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Revision date: April 7, 2023

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What is Shiba shrimp (Shiba-ebi) sushi?

a photo of Shiba ebi — Even if you look at it favorably, the color of Shiba shrimp (Shiba-ebi) does not make it look delicious.

What is Shiba shrimp (Shiba-ebi)?

Shiba shrimp (Shiba-ebi) is distributed south of Tokyo Bay on the Pacific Ocean side, south of Niigata Prefecture on the Sea of Japan side, and along the coast of China. It lives in sandy mud at depths of 10 to 30 m in inner bays, and grows to about 15 cm in length. The shell is thin, without stripes, and light yellowish-gray in color. They are also called Akahige (Aka means red and hige means antennae.) in some regions because of their red antennae. The season is from November to March. It was once caught in large numbers off the shiba coast of Tokyo Bay, hence the name shiba-ebi. It is important to note that Shiba shrimp lose their freshness quickly and the heads darken quickly, so they should be cooked on the same day or the heads should be removed. The main production areas are the Ariake Sea in Kyushu and Mikawa Bay in Aichi Prefecture. Its scientific name is Metapenaeus joyneri (Miers.1880).

What does Shiba shrimp (Shiba-ebi) sushi taste like?

a photo of Kakiage — Recently, whiteleg shrimp, which is less expensive, is used as an ingredient in Kakiage (seafood tempura) instead of Shiba shrimp.

Shiba shrimp is generally used in seafood tempura, Chinese cuisine, etc. When made into sashimi, it has a light and elegant taste, but the texture and sweetness are not quite enough.

a photo of oboro nigiri — Some sushi chefs serve Oboro nigiri like a dessert at the end of the meal.

It is not a typical ingredient for Nigiri sushi, but it is indispensable at sushi restaurants. It is used as an ingredient in Oboro and Tamagoyaki. Rarely, you will see sushi chefs making Gunkanmaki, but it looks grayish-white and not very tasty, and the delicate taste of Shiba-ebi is masked by the flavor of the nori seaweed.

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Revision date: April 5, 2023

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What is Sweetfish (Ayu) sushi?

a photo of Ayu (Sweetfish) — A small sweetfish is used for nigiri sushi.

What is Sweetfish (Ayu)?

Sweetfish (Ayu) is distributed throughout East Asia from southern Hokkaido to Kyushu, the Korean Peninsula, and northern Vietnam. The species found on Amami-Oshima Island and Okinawa Island is called Ryukyu-ayu and is a differentiated subspecies. Ayu is characterized by the oval yellow spots on the upper pectoral fins and a dozen rows of comb-like teeth aligned on the lip.

It is born near the estuary in the fall, goes down to the sea to overwinter, returns upstream the following spring to become an adult, and then migrates back downstream to spawn and live out their lives. In some lakes, such as Lake Biwa, a land-locked type is found that completes its life in the lake instead of the ocean. These groups are called Ko-ayu. Aquaculture is also popular, with Gifu, Hiroshima, Kochi, and Kyushu being well-known production areas. The scientific name is Plecoglossus altivelis altivelis (Temminck and Schlegel, 1846).

The traditional names used to describe the fish are “Kou-gyo (fragrant fish)“ (because of its unique scent), “Nen-gyo (annual fish)“ (because it usually lives only one year), “Ginko-gyo (silver-lipped fish)“ (because its mouth glows silver when it swims), Keiun (means sardine in a mountain stream) and “Sairin-gyo (scaled fish)“ (because of its small scales).

What does Sweetfish (Ayu) sushi taste like?

a photo of Ayu sushi — When making nigiri sushi, the head of the ayu fish is sometimes left on or the skin is removed.

Adult ayu feeds on algae on the surface of stones in the river, giving them a distinctive aroma like that of watermelon or cucumber, which can already be smelled even by young fish in the upstream season. The season is from July to August when ayu put on fat, but the aroma is stronger when young ayu are caught a little earlier.

When preparing nigiri sushi, small wild ayu is used, the head and entrails are removed, and the belly is cut open and the inside bone is removed. In traditional Ayu sugata sushi (whole fish sushi), the fish is thoroughly salted to drain off the water and make it strong sujime. Then let it rest in the refrigerator for half a day. If the fish is small ayu, the skin can be left on, but if the size is large or the sushi is to be made immediately after soaking in vinegar, the skin is often felt hard, so it is removed. Ayu belongs to Hikaramono in the sushi category, perhaps because of its shiny appearance. There are very few sushi chefs who make Ayu’s nigiri sushi, so Sushi Sanshi (鮨三心), Sushi Ikko (鮨一幸), Kanda Sasazushi (神田笹鮨), etc. have it on their signature menu. It was the most popular autumnal sushi item during the Edo period.

a photo of Ayu shioyaki — When eating salt-grilled ayu fish, it is good manners to taste the whole fish, but the head and tail can be left behind.

To enjoy the elegant appearance and aroma of ayu, grilled with salt is the best way to go. The fish is put on a skewer in such a way that their body forms a wave, making them look as if they are swimming (it is called uneri gushi). It is traditionally eaten with water pepper vinegar, which goes well with it.

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Revision date: July 4, 2023

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What is Stone flounder (Ishigarei) sushi?

a photo of Stone flounder (Ishigarei) — Sushi aficionados will appreciate it as a truly extravagant sushi nigiri.

What is Stone flounder (Ishigarei)?

Stone flounder (Ishigarei) is distributed along the coasts of Japan, the Kuril Islands, Sakhalin, the Korean Peninsula, and Taiwan. It lives in sandy mud at depths of 30 to 100 meters, and its total length reaches 50 cm. The body surface is smooth with no scales, but there are large longitudinal bony plates on the dorsal surface of the body on the eye side and other small bony plates. In Japan, depending upon the region it will be called other names, such as Ishimochi, Ishimochigarei, or Shirogarei.

It was caught in large quantities by bottom trawling fishing and was synonymous with cheap flounder. However, since the Edo period (1603-1867), it has been treated as a luxury fish in Tokyo. This is because white fish are scarce in summer, and even now, as summer approaches, the price rises along with Japanese sea bass (Suzuki) in the market. However, there was a time when it became a phantom fish that could not be caught at all due to the reclamation and development of Tokyo Bay that began after World War II.

What does Stone flounder (Ishigarei) sushi taste like?

Stone flounder is made by quickly removing the bony plates during the preparation process to avoid the characteristic muddy smell of flounder. It has clear, elegant flesh with a moderate aroma of the sea and a rich flavor with just the right amount of crunchiness. It caught in Tokyo Bay is highly prized and is served as sashimi and sushi, but it is also delicious simmered, or grilled.

As a rule, only live fish can be used for nigiri sushi. Nojime and Ikejime are also not highly valued because the umami component of flounder rapidly decreases after death. Stone flounder, which can be found in abundance in supermarkets at reasonable prices, cannot be used for nigiri sushi or sashimi. It also has a distinctive odor when it is no longer fresh, so it is best to remove it quickly and remove the skin. Skinless fillets can be enjoyed even after maturing for a while.

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Revision date: March 17, 2023

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What is real Omakase at a sushi restaurant?

Omakase sushi experience — She is very interested in eating sushi toppings for the first time.

We’ll start by breaking down the meaning of this word in Japanese.

The “O” of “Omakase” is a prefix generally used as an honorific expression. The meaning of “makase” refers to a judgment of things and means to entrust a task you were meant to do to someone else, allowing them to perform the task at their own discretion. In terms of sushi, while a customer normally chooses which toppings they want to eat on their own, a customer with limited sushi topping knowledge may ask the chef to prepare his own recommendations.

There are various other ways to order sushi toppings as well. First, sushi restaurants generally have a set menu called “Okimari.” For example, let’s consider an Okimari set that contains 8 pieces of nigiri sushi. This set of 8 pieces will contain the same toppings and maintain the same price throughout the year. In contrast, a customer may choose the number of toppings they like in whatever order they prefer, such as ordering two pieces each of four types of toppings, which is called “Okonomi.” They can even order eight of the same topping. The price for “Okonomi” depends on what is ordered, the more expensive the toppings are, the higher the price will be. For “Omakase,” the chef would select 8 toppings and serve them in his recommended order. However, the customer conveys their budget to the chef in advance so the sushi course can be provided within that budget. The customer can also specify toppings they prefer to avoid. In other words, you need to let the chef know in advance about your budget according to the market, and any requests (For example, I would like to eat the Splendid alfonsino (Kinmedai) in season) that you can’t budge on. You don’t need to leave those two things up to the chef’s discretion.

Now, in actuality, there are many sushi restaurants that stray from the original definition of “Omakase.”

For instance, he/she may include Tsumami as part of the course, rather than only sushi. This would be Sushi Kappo (sitting at the counter to enjoy Japanese food and served directly by the chef). A sushi restaurant was once a place where only Nigiri sushi was served. To explain in more detail, if only Nigiri sushi is served, then even if you were to eat 20 pieces of Nigiri sushi, your time in the restaurant would only be around 30 minutes (this is true the case of the establishment of the famous Jiro). Nowadays sushi restaurants are used for entertaining business clients or going on dates, so the customer may stay for around two hours. In situations like this conversation is the priority, so the actual ordering of the sushi takes the backseat. Incidentally, the practice of drinking Japanese sake at sushi restaurants is said to have begun around 1910.

Next, we’ll let you in on a common misconception that you probably don’t want to hear.

Apparently, people believe that ordering Omakase means that you will be served rare pieces that are not disclosed on the menu. Some are even convinced that they can get more expensive toppings than they would if they ordered with the Okonomi method. However, the restaurant just sets the price for the Omakase course and just adjusts the menu items accordingly (to suit the budget) based on current stock. The benefit to the restaurant is that it only stocks the amount of seafood necessary and will waste less. Unfortunately, rare finds are reserved for customers who know what they like. Go ahead and toss any such expectations out of your mind right now. Instead, acquiring sushi knowledge will allow you to avoid being recommended toppings that are approaching expiration.

Finally, if you just get an expensive Omakase course without understanding where the toppings came from or when they are in season, then it won’t contribute to your deeper understanding of the magnificence of Nigiri sushi.

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Revision date: April 18, 2023

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Nigiri sushi should be eaten when the fish is in season!

a photo of Mackerel — Mackerel is now in season.

Each food has its own season. It goes without saying that the taste is at its best at that time of year.

When is this “season”?

Most people would answer that it is the time of year when food can be harvested in abundance. This is certainly true for fruits and vegetables. However, this is not always the case with fish. Fish season refers to “the time when the fish is at its peak of fat content,” which does not necessarily coincide with the time when the food is in abundance.

Then, what determines when fish are in season, is the relationship with the spawning season, which is the most important factor. One to two months prior to spawning, both male and female fish feed frantically. This is the time of year when the fish are fat, fatty, and delicious. This is the fish’s season.

However, when the spawning season arrives, the fish become thin. This is because all the nutrients in the body are absorbed by the testes of the males and the eggs of the females. Especially immediately after spawning, the fish have used up all their energy, and their flesh is in a very shabby state.

In other words, the timing of eating the fish is off by just a few days, and the fish tastes considerably less good than when it is in season.

We think you get the idea by now.

You are bound to order fish out of season due to your lack of knowledge. To avoid wasting your money, you should know the season of typical sushi items.

The seasons of typical fish are as follows.

Spring: Japanese halfbeak (Sayori), Ark shell (Akagai), Red seabream (Tai), Pacific herring (Nishin), Black Rockfish (Mebaru), Firefly Squid (Hotaru ika)

Summer: Japanese conger (Anago), Bonito (Katsuo), Horse mackerel (Aji), Greater amberjack (Kanpachi), Goldstriped amberjack (Hiramasa), Daggertooth pike conger (Hamo), Japanese sea bass (Suzuki), Sea urchin (Uni), Japanese whiting (Kisu), Chicken grunt (Isaki), Common scallop (Hotate)

Autumn: Pacific saury (Sanma), Mackerel (Saba), Gizzard shad (Kohada)

Winter: Bastard halibut (Hirame), Japanese amberjack (Buri), Bluefin tuna (Kuro maguro), Japanese pufferfish (Fugu), Splendid alfonsino (Kinmedai), Golden cuttlefish (Sumi ika)

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Revision date: February 27, 2023

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What is Katsuobushi?

a photo of Katsuobushi — Of the ingredients used to make dashi, katsuobushi is the most common.

Katsuobushi (鰹節) appears frequently in documents from the Muromachi period (1333-1573) and later, and was used then, as it is now, to take dashi. The name Tosa-bushi is also found in documents from the early Edo period (1603-1868), but the method of making it seems to have been to boil it down and then dry it in the sun, and it is said that the current molding method was invented around 1673~81. In the Tosa Domain, which has been famous for bonito fishing since ancient times, Harimaya Sanosuke of Usa and Yamazaki Giemon of Nakahama worked to improve and popularize Tosa-bushi, and the name Tosa-bushi spread as a specialty of the domain in Edo and Osaka.

The process of making katsuobushi begins by boiling the formed bonito meat in boiling water, removing the bones and some of the skin, placing it in baskets, and then placing it in a chamber to be heated and dried over a fire made of oak, sawtooth oak, or kashiwa (oak tree). This is called Baikan (焙乾).

At this stage the product to be shipped is called Namabushi. The first Baikan is called Ichiban-bi. After that, the cracks and missing parts of the Fushi are repaired with bonito surimi. The baikan is repeated once a day for 2 to 12 times. In case you are wondering, Katsuobushi before shaving is called Fushi.

After Baikan, it is called Arabushi (荒節) or Onibushi (鬼節). After drying in the sun for a few days, the surface is scraped with a small knife and called Hadakabushi (裸節), Akamuki (赤むき), Wakabushi (若節), Shinbushi (新節), etc. After drying in the sun again, it is placed in a wooden box called Kabi-tsuke-bako for 15 to 17 days in a cool and dark place, and the surface of the Fushi is covered with blue-green mold. This initial molding is called Ichiban-kabi (一番黴). This process is repeated, and those that have been processed for Niban-kabi are called Aokarebushi (青枯れ節).

This process is usually repeated four times, and when the Yoban-kabi (四番黴) process is completed, the product is called Hongarebushi (本枯れ節). This process is very effective in reducing the fishy smell and fat content of the Fushi and improving its flavor and color.

The best Katsuobushi is the one that is well-dried, has a tortoiseshell-like color, and a clear metallic sound when tapped. When buying katsuobushi with high-fat content or oxidized fat, the surface color may be white or yellowish-brown, so care should be taken when purchasing katsuobushi.

Kezuribushi made by shaving Hongarebushi is called Katsuobushi-kezuri (鰹節削り). On the other hand, shaved Arabushi is called Katsuo-kezuri (鰹削り). Katsuobushi-kezuri has a milder fragrance than Katsuo-kezuri and is relatively light. This is because the mold softens the smoky smell of Baikan and the fishy smell of fish.

Generally, Arabushi is used mainly in Kansai, while Hongarebushi is preferred in Kanto. The reason for this goes back to the Edo period (1603-1867). At that time, Katsuobushi was transported to Edo by sea from western Japan, including Tosa, Satsuma, and Kishu. However, because mold grew during the voyage, it was dried in the sun and eaten, which added a mild aroma. Since then, mold-dried Katsuobushi has been favored in Edo.

Kezuribushi varies in thickness. Usukezuri (薄削り) is 0.1 mm or less and is used as Hana-katsuo (花かつお) for decoration, and is not suitable for making dashi. Nakakezuri (中削り) is around 0.2 mm thick and is generally used at home because it can be used to make dashi in a short period of time. Atsukezuri (厚削り) is about 0.7 mm thick and should be boiled for about 20 minutes to make dashi.　Atsukezuri is rarely used by itself but is often blended with several types of Fushi for commercial use.

Kezuribushi is all about the aroma. To prevent volatilization and oxidation of the aroma, it should be sealed in a plastic bag, with the air inside pushed out, and stored in a refrigerator or freezer. Even though it is dry food, it needs to be handled in the same way as fresh food.

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Revision date: February 21, 2023

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What is Gyosho (fish sauce)?

Shiokara (salted fish guts) and Gyosho (fish sauce) are widely produced throughout East Asia and are very similar foods in terms of their ingredients and production methods.

Gyosho is made by preserving raw seafood in salt. It is a fermented food in which the raw materials are broken down into amino acids, mainly by the action of enzymes contained in the raw materials, and the umami is intensified. There are solid and liquid products leached from it.

The production process is not much different from that of salted fish, but salted fish is intended for long-term preservation of protein sources, whereas gyosho is produced for use as a seasoning. It is originally obtained as a byproduct of salted fish, but nowadays, it is produced only for the purpose of obtaining Gyosho.

However, most of the Shoyu produced in Japan is made from cereal grains, and the amount of gyosho produced for local consumption is minimal.

Types of Gyosho

Shottsuru

Shottsuru has long been produced in the Akita area. Sailfin sandfish (Hatahata) is the most well-known fish used, but Sardine and Pacific sand lance are also used. First, the fish’s head, entrails, and tail fins are removed, and the fish is washed in water. Then the fish is drained, and about 10 kg of fish is mixed with about 1,800 ml of rice malt and 1,800 ml of salt, packed in a wooden barrel, covered with a lid, and weighted down. After maturing in a cool, dark place for about three years, the fish is filtered and boiled to make the product.

Ishiru

Ishiru is made in the Okunoto region. There are other names such as Ishiri, Yoshiru, and Yoshiri. The fish used are sardine, round herring, horse-mackerel, etc. The meat is often processed into dried fish, and the surplus heads and entrails are used. About 30% salt is added to this, packed in miso barrels, covered with a sheet, and aged for six months to a year. After that, it is boiled and filtered to make the product.

Ishikawa Prefecture also produces “Ishiri,” which is easily mistaken for “Ishiru,” but it is made from the entrails of the Japanese common squid.

Nam pla (น้ำปลา)

Nam pla is an essential seasoning for Thai cuisine. In Thai, nam means liquid and pla means fish. In the traditional method, small marine fish, starting with sardine, are mixed with 30~40% salt by weight and placed in a large jar for maturing.

After about a year, a long, thin bamboo basket is inserted into the jar and the liquid that has leached out is drawn out and bottled to make the product. Inland, freshwater fish such as Carp and Loach are used. There is also a theory that the origin of Nam pla is to use freshwater fish.

Anchovy sauce

Gyosho, called garum, was widely used in ancient Rome around the 1st century BC. Bluefish such as mackerel would be pickled in salt, stuffed into unglazed jars, and maturing under the sun. The garum that flowed out through a hole drilled in the bottom of the jar was then used as a seasoning. In Italy, garum production stopped around the 16th century.

Anchovy sauce, a similar product made by maturing salted round herring for six months or more, grinding it, and adding spices, is now used as a secret ingredient in spaghetti and other Italian dishes.

Nước mắm

Nước mắm is mainly made from Round herring and Amberstripe scad in Vietnamese Gyosho, and Carp, Loach and Catfish fry are also used around the Mekong Delta. The cleaned fish is placed in a container with 10~15% salt by weight, stirred every morning, and salt is gradually added until it reaches a concentration of about 30%, depending on the progress of maturing. Those aged for one year or more are more delicious. Gyosho from Đảo Phú Quốc is considered the best.

Colatura

Colatura is an Italian Gyosho. It is made from nothing but round herring and salt. The round herring is first removed from the head and entrails and placed in a barrel, alternately layered with salt. Then, a wooden lid is placed on the herring, and weights are placed on top of it for maturing.

After maturing for three to four years, a hole is drilled in the bottom of the barrel and the Colatura is slowly extracted, drop by drop, over time. The slow aging process in the barrels concentrates the flavor of the fish and produces the amber-colored Colatura.

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Revision date: February 20, 2023

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