Sushi Ingredients | Sushiblog－Sushiuniversity

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.

10 pieces of sushi we recommend for February

This is a list of 10 must-try sushi toppings in February. Hamaguri was once harvested in abundance from Tokyo bay, and even today is a fundamental ingredient in Edomae sushi.

Red seabream (Tai)

Blackthroat seaperch (Nodoguro)

Golden cuttlefish (Sumi ika)

Lean meat of tuna (Akami)

Medium Fatty Tuna (Chutoro)

Spear squid (Yari ika)

Pen-shell (Tairagi)

Ark shell (Akagai)

Rediated trough-shell (Kobashira)

Common orient clam (Nihamaguri)

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Revision date: January 22, 2018

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.

10 pieces of sushi we recommend for January

This is a list of 10 must-try sushi toppings in January. Tai is always served at celebratory occasions in Japan.

Longtooth grouper (Kue)

Red seabream (Tai)

Golden cuttlefish (Sumi ika)

Lean meat of tuna (Akami)

Medium Fatty Tuna (Chutoro)

Botan shrimp (Botan ebi)

Mirugai clam (Mirugai)

Ark shell (Akagai)

Sakhalin surf clam (Hokkigai)

Japanese oyster (Kaki)

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Revision date: November 6, 2020

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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Why do some sushi toppings have ginger instead of wasabi?

Ginger is used for toppings with a strong, distinct taste and strong fishy smell such as bonito, horse mackerel and sardines.

Wasabi has a spicy taste and stimulates the senses of taste and smell and works to dull the senses so the fishy smell is not felt, but ginger is effective in actually extinguishing the fishy smell.

Because the effect of wasabi is transient and difficult to sustain, it is not a good match for fish with a peculiar odor in some respects. For this reason, it is often used with white fish that have a lighter flavor.

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Revision date: January 13, 2023

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10 pieces of sushi we recommend for December

This is a list of 10 must-try sushi toppings in December. The proficiency of a sushi restaurant can be distingusihed by the quality of the maguro they buy.

Red seabream (Tai)

Red gurnard (Houbou)

Golden cuttlefish (Sumi ika)

Lean meat of tuna (Akami)

Medium Fatty Tuna (Chutoro)

Japanese pufferfish (Fugu)

Japanese spanish mackerel (Sawara)

Ark shell (Akagai)

Sakhalin surf clam (Hokkigai)

Splendid alfonsino (Kinmedai)

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Revision date: November 6, 2020

You know toro tuna and akami, but have you heard of the more rare parts of the tuna?

A single bite of the same bluefin tuna differs greatly depending on the part of the fish it came from.

The body of the fish is broadly categorized into the dorsal (back) and the ventral (belly) sides, which taste completely different. Of course the meat near the head tastes completely different from the meat near the tail. If you dig even deeper, there are parts that aren’t as well-known as the Otoro (fatty), Chutoro (medium fatty) and Akami (lean) tuna meats. We’d like to explain those now.

“Hachinomi (ハチの身) or Tsunotoro Nouten” is the meat from the crown of the head. It is fatty and rich and also called “Head Toro”. Only about 1kg of this precious meat can be taken from even a very large fish, and it is only shared with regular, loyal customers.

“Kamatoro (カマトロ)” is taken from behind the jaw. It is known as “shimofuri (霜降り)” or marbled meat. There are no veins in this part so the meat is soft and the marbling is more detailed than Otoro, so it is sticky and melts in your mouth. The balance of fat and sweetness in this part is unparalleled. It can be said that otoro (such as shimofuri and jabara) of tuna is the representative part of toro tuna. This is an image of the shimofuri on the right, and the jabara (蛇腹) on the left.

“Chiai (血合い)” is the part with the most veins, so it is a dark red color. It has a strong odor of blood and has multiple times the acidity of the lean meat, so it is not used as a sushi topping.

“Chiai Gishi (血合いぎし)” －Located right next to chiai, this is the meat you can taste the umami of the rich red meat and the sweetness of toro fat at the same time.

“Wakaremi (分かれ身)” is a precious part with very little meat found next to the dorsal fin. The part especially close to the dorsal fin is popular and called “Setoro (背トロ)”. Setoro has both the umami of akami and the umami of fat. The fat isn’t overbearing so you can eat a ton. However, this part is hard to get, even in high-quality tuna and is not available except to regular customers in almost all sushi restaurants.

A sushi chef, Hiroyuki Sato, serves a tossaki hand roll as the first sushi piece of the course. “Tossaki (突先)” is an exclusive cut of tuna that goes well with sushi rice using red vinegar, which is less sour but has more umami and flavor compared with white vinegar. Because tossaki is the base of the tuna’s head and it moves a lot, there are a lot of muscular striations. Therefore it needs to be prepared using the back of a knife carefully as if peeling it off (Hagashi). It is said that tossaki is a high-tuna-flavor cut. A couple of Sato’s apprentices also offer a hand roll to open up the meal in the same way.

The meat of tuna gets leaner and muscular striations are fewer towards the inner center of the body. “Tenpa (天端)”, surrounding the spine, is deeper in color and tastes stronger. It features the tender texture coming from the finest meat quality. This is also called Tenmi (天身).

“Hohoniku (ホホ肉)” or cheek meat is taken from below the eye, seasoned, grilled and made into gun-kan rolls. The taste is enhanced in this part by grilling.

“Hireshita (ヒレ下)”－Located right above the first pectoral fin. Characterized with the tender meat which is relatively low in fat content but rich with umami flavor. This truly is the valuable part of whether there will be even enough for 10 pieces of sushi from an over 200 kg tuna.

If you are fortunate enough to get an opportunity to taste these, you can take it as proof that you have been accepted as a regular and loyal customer. It is difficult to distinguish these parts by appearance alone, so make sure you try them at a sushi restaurant you can trust. Just for your reference.

Today you will learn how to easily identify artificial salmon roe!

The natural salmon roe season is the autumn. Does this mean that most of the roe eaten during the off-season is artificial Salmon roe. Not necessarily. As stated in his biography, even at the famous sushi restaurant Sukiyabashi Jiro, frozen roe is thawed as necessary.

Long ago this was an extremely expensive topping that ordinary people couldn’t afford, so artificial roe was used. There was a time when this was the case. But nowadays salmon roe is regularly imported from overseas and can be obtained cheaper, eliminating the need to use artificial roe instead.

However, we cannot overlook the commercial law for passing off artificial roe as natural roe. In Japan, the non-perishable properties of artificial salmon roe made from chemical substances (mainly sodium alginate) is utilized and used mainly in hospitals, but not sold to the general public. I’ll also tell you that it is very rare to find a sushi restaurant that serves artificial roe. Cheap roe is generally made from eggs of trout, other related species, or imported from Canada and other countries.

Unfortunately I’m not familiar with the state of things outside of Japan, but I can tell you how to tell the difference. All it takes is hot water and a moment of observation. Artificial salmon roe will show no changes in hot water, but natural roe will start to turn white on the surface. This is due to the protein reacting and changing with the heat. That said, this is not an experience you can just set up at the sushi restaurant.

The following describes the artificial salmon roe composition. The nucleus of artificial salmon roe is made of red-colored vegetable oil, the thin outer film is made of sodium alginate or carrageenan, and the sol-like contents are made of polysaccharides derived from seaweed, Gum arabic, and Xanthan gum. While real salmon roe is high in polyunsaturated fatty acids, artificial salmon roe is high in saturated fatty acids derived from vegetable oils, oleic acid and linoleic acid.

As an aside…

What are the fish eggs on sushi called in Japan?

There are eight types of fish eggs served at Japanese sushi restaurants. However, not all of them are used for Nigiri sushi. Some are served as side dishes. Uni is sometimes translated as sea urchin’s roe, but it is actually the sea urchin’s genitals (testes and ovaries). Most people also don’t know that Tobiko and Tarako are not served at 99% of Edo-style restaurants. In other words, these toppings are only served at kaiten-sushi (conveyor belt) restaurants. The one type of roe topping that can probably be found at all sushi restaurants is Ikura. Even more types of fish eggs, such as Masago, Paddlefish roe and Hackleback roe are used in sushi overseas, but Japan remains more conservative. Of course, it’s only natural that fish substitutes are not well-received in the place where sushi was born.

Types of fish roe

Fish roe usually cannot be preserved as is, so it is salted or smoked to make it last longer. Today, thanks to advances in freezing technology, frozen fresh fish roe is also available, but as a raw material for processing, fish roe is often salted to reduce its water content and then frozen for preservation. Nutritional value is generally high in fat and protein and low in carbohydrates, with higher calories and cholesterol than the meat of the parent fish.

What is Ikura? － It is Salmon roe.

What is Kazunoko? － It is Herring roe.

What is Sujiko? － It is Salmon roe that is still within its egg membrane.

What is Tobiko? － It is Flying fish roe.

What is Tarako? －Tarako is the salted ovary of Alaska pollack. It is often colored red with food coloring. Karashi-mentaiko is Tarako marinated in a seasoning solution of salt and chili peppers, and is a well-known Hakata specialty. The name Karashi-mentaiko comes from the Korean word for Alaska pollack, Mentai.

a photo of Tarako nigiri sushi — Tarako nigiri sushi is very rare, even in conveyor-belt sushi.

What is Caviar? － It is Sturgeon roe.

What is Karasumi? －It is made by salting, aging, and drying the ovaries of Flathead gray mullet (Bolla). The product resembles Chinese ink karasumi, hence the name. Good ones are candy-colored, cut into thin slices, lightly roasted, and served as nibbles for drinks. Imports have been increasing recently, but the most famous domestic product is karasumi from Nomo, Nagasaki Prefecture.

What is komochi konbu? － It is Herring spawn on kelp.

What is Capellinko? － It is Capellin roe.

a photo of Capellinko gunkamaki — Capellinko (Capellin roe) is a substitute for Tobiko (Flyingfish roe).

What is Madarako? － It is Pacific cod roe.

What is Masuko?－ It is Humpback salmon roe.

a photo of Masuko gunkanmaki — In Japan, Humpback salmon roe is called Masuko and Chum salmon roe is called Ikura.

What is Masago? －What’s the difference between Tobiko and Masago?

Just for your own information.

Related contents：

What is Artificial caviar?

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Revision date: August 9, 2023

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10 pieces of sushi we recommend for November

This is a list of 10 must-try sushi toppings in November. This is when Zuwaigani (Snow crab) fishing season opens. Kanbirame is caught in mid-winter. Its meat is so firm that when bitten into your teeth almost bounce back.

Bastard halibut (Hirame)

Filefish (Kawahagi)

Japanese amberjack (Buri)

Lean meat of tuna (Akami)

Medium Fatty Tuna (Chutoro)

Gizzard shad (Kohada)

Whelk (Tsubugai)

Mackerel (Saba)

Common octopus (Madako)

Snow crab (Zuwaigani)

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Revision date: October 30, 2017

Why is sushi eaten with sushi sauce (shoyu)?

There are many different things all over the world that are share the name “sushi”. However, when Japanese people hear this word they think of “nigiri sushi”. Of course outside of Japan, it probably more commonly refers to sushi rolls.

Similarly, the way soy sauce is used also differs greatly between people in Japan and those in other countries. The soy sauced used for nigiri sushi is not used to add salty flavor to the sushi. The reason it’s used is to subdue the fishy odor of the fish and to add the many amino acids contained in soy sauce to nigiri sushi, which brings out the umami synergistic effects. Think of it more like an important background role to the sushi that isn’t meant to stand out. Meanwhile, since sushi rolls and other sushi dishes overseas are generally eaten after being cooled, the flavor is subdued, leading to using large amounts of soy sauce.

There is also a big difference in the concept of sushi sauce. In Japan, there is no such word as “sushi sauce”. Neither chefs nor the general population has heard this term. However, the term is easy to imagine what it would be, so hearing the word “sushi sauce” would probably lead Japanese people to assume it meant nikiri shoyu or nitsume, which are used in nigiri sushi. Also, soy sauce, or “shoyu” as it’s called in Japanese, is not considered to be a type of “sauce” in Japan. But what about in other countries? Sushi sauce has a distinctive, assertive flavor and is added to bring out multiple layers of flavor. There are also many types of sushi sauce such as sriracha sauce, spicy mayo, mango sauce, ponzu sauce, tonkatsu sauce, eel sauce, tamari sauce, teriyaki sauce, dynamite sauce and others. They each play an important role in bringing out the flavors of sushi rolls that otherwise wouldn’t be apparent.

In other words, as the definition of sushi definition changes across borders, the definition of sushi sauce changes too. However, what both sushi sauce overseas and Shoyu in Japan have in common is that they complement the sushi they are used for.

Now we would like to explain a bit about the Shoyu used in nigiri sushi.

Edo style sushi was created during the Edo period in Japan (1804-1830). The expansion of the soy sauce culture of the Edo area (currently Tokyo) had a big influence on the creation of Edo style sushi. In a time when refrigeration and other technology had not yet been developed, soy sauce played an important role not only in taste, but also in preservation. A surprising number of tasks in the Edo style utilize the scientific effects of soy sauce.

First of all, lightly applying just a small amount of Nikiri shoyu (sushi sauce) on the sushi topping, brings out its flavor and creates a glaze. To put it scientifically, this a clever use of the odor eliminating effects of soy sauce, eliminating the raw odor.

Also, long ago zuke (soaking in soy sauce) was also used for fish other than tuna. This was a way to utilize the bacteriostatic effects of soy sauce, which stop the growth of Escherichia coli (E. coli).

Tsume (sushi sauce) represents the thermal effects of soy sauce. By adding soy sauce, mirin and sugar then boiling down, the amino acids in the soy sauce and the sugar react and the goal is to create a delicious glaze and a nice scent that stimulates the appetite.

Adding a small amount of soy sauce when making rolled egg omelets has the effect of enhancing and bringing out the flavor and sweetness of the ingredients.

Soy sauce is generally overshadowed by the sushi topping and vinegar rice, but soy sauce plays an important role in bringing out and enhancing the delicious taste of the sushi.

10 pieces of sushi we recommend for October

This is a list of 10 must-try sushi toppings in October. Considered the king of the silver-skinned fish, it has been a staple ingredient used in sushi since edomae sushi first appeared.

Bastard halibut (Hirame)

Young Japanese amberjack (Inada)

Swordtip squid (Kensaki ika)

Lean meat of tuna (Akami)

Medium Fatty Tuna (Chutoro)

Gizzard shad (Kohada)

Alaskan pink shrimp (Ama ebi)

Mackerel (Saba)

Pacific saury (Sanma)

Japanese conger (Anago)

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Revision date: October 1, 2017

A Guide to Avoiding Food Fraud!

It is true that in an age when aquatic resources are being depleted, there is a worldwide demand for a substitute for luxurious fish. However, although it’s not easy to tell fish apart once it’s sliced, that doesn’t mean that restaurants should not be held to certain standards. Here we present a number of severe cases.

First of all, Opah belly meat with some fat is used for the tuna in Negi-toro (tuna minced with Welsh onion leaves). Opah is widely distributed in warm seas and it’s known to be inexpensive with a smooth taste. The price is less than 1/100 of the Pacific bluefin tuna and if possible Negi-toro made from Opah should be avoided.

Next let’s discuss Japanese conger, an essential Edo-style sushi topping. A substitute for Japanese conger is the Common snake eel, which is a type of sea snake from Peru. The taste is pretty good, but the skin is rubbery and it doesn’t stick to the Shari (vinegar rice) so it’s instantly apparent that it’s a substitute fish. If you find Japanese conger at kaiten-zushi for JPY 100 per plate, you might want to question the source.

A premium sushi topping is the Mirugai clam (also called Hon-miru). This shellfish is characterized by its unique texture and taste. Instead the Japanese geoduck (Shiro-miru) is used, which sells for half the market price. However, the taste of the two is so similar that even Sushi Tsu has mistaken them, which is great news for dishonest dealers.

In April 2015 the Food Labeling Act was revised, leading to progressive reduction of fraudulent labels, but it is not a solution that eradicates dishonest dealers so consumers need to be educated and aware.