Nikiri is a short form of nikiri shoyu in which an alcohol-evaporated mirin, sake, soy sauce and dashi broth are added together. Since raw soy sauce is too strong a taste for sushi, brush sushi lightly with nikiri is tasty enough to eat.
The most delicious way to eat sushi at restaurants where the sushi chef applies Nikiri (soy sauce perfectly evaporated with sake) for you is just the way it was prepared. However, at restaurants where sauce is not applied for you, the sushi is eaten by dipping it in soy sauce. The soy sauce used for dipping is provided for you at the counter or table. Many restaurants use the same evaporation formula for the dipping soy sauce.
Soy sauce for dipping is put into a small dish for use, but don’t put in too much. It depends on the depth of the small dish, but the diameter of the circle of soy sauce after being poured should be approximately 25mm.
When dipping sushi into the soy sauce, turning it upside down (although it will be somewhat tilted) and dipping the topping seems to be the most common method. If you keep the topping on the bottom when you put the sushi in your mouth, the flavors of the soy sauce and the fish are in complete harmony and the delicious taste spreads through your mouth. There is also an opinion that turning the sushi upside down for dipping is unacceptable practice. There are also some with the opinion that whether to eat with your hands or chopsticks depends on the situation.
Make sure not to get any soy sauce on the Shari (vinegar rice). You don’t want to add unnecessary saltiness to the Shari, which has already been seasoned. It would be a terrible waste to cancel out the exquisite balance of the topping, wasabi and Shari with the saltiness of soy sauce.
A surprising number of tasks in the Edomae style utilize the scientific effects of soy sauce.
Many different things all over the world 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 sauce used for nigiri sushi is not primarily intended to add saltiness. Rather, it serves to suppress the fishy odor of raw fish and to enhance umami by adding the many amino acids found in soy sauce. Soy sauce is especially rich in glutamic acid, which, when combined with inosinic acid naturally present in the fish, creates a synergistic umami effect. Think of it more like an important background role to the sushi that isn’t meant to stand out.
On the other hand, overseas, sushi such as rolled sushi is generally eaten cold, and since the flavors such as sweetness, umami, and aroma fade at low temperatures. when it cools, there is a tendency to use more soy sauce. To compensate for this flavor fade, stronger seasonings such as sriracha sauce, eel sauce, and teriyaki sauce are often used, so that the flavor of the sushi does not get lost even when it cools.
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.
Edomae 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 Edomae 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 Edomae 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 natural umami flavor and also creates an attractive glossy glaze. Scientifically, this technique leverages the odor-masking properties of soy sauce, which contains sulfur-containing compounds such as methanethiol (methyl mercaptan). These compounds chemically interact with and neutralize unpleasant raw fish odors, effectively masking the “fishy” smell and enhancing the overall sensory experience.
Historically, zuke (soaking fish in nikiri soy sauce) was not limited to tuna but applied to other types of fish as well. This traditional method takes advantage of the bacteriostatic effects of soy sauce—its high salt concentration and presence of antimicrobial peptides inhibit the growth of harmful bacteria like Escherichia coli (E. coli), thereby preserving freshness and enhancing food safety.
Tsume, a thickened sushi sauce made by boiling down soy sauce with simmered conger eel sauce, mirin and sugar, demonstrates the thermal chemical reactions involved in soy sauce cooking. The Maillard reaction between amino acids from the soy sauce and reducing sugars creates a rich brown glaze and complex aroma that stimulates appetite. This reaction also contributes to the development of subtle caramelized flavors, enhancing the sauce’s depth.
In addition, adding a small amount of soy sauce when making rolled egg omelets (tamagoyaki) enhances and harmonizes the natural sweetness and umami of the eggs and other ingredients. This effect is primarily due to the presence of free amino acids in soy sauce. Sweetness is imparted by amino acids such as glycine, while umami arises from the combined action of approximately 20 different amino acids. Among these, acidic amino acids like glutamic acid and aspartic acid, as well as basic and neutral amino acids such as lysine and alanine, contribute most significantly to the overall umami profile.
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.
Zuke is one of the traditional Edo-style sushi methods. It is said that it was started in the Edo period to stop tuna from rotting when there were large amounts of the fish in the market. Now that there has been advances in refrigeration technology, it’s no longer necessary, but maturing the fish gives it a completely different taste and brings out its umami. Zuke is divided into two broad methods. Here we describe the characteristics of each.
Recently, most sushi restaurants incorporate the “Single Zuke”.
Each slice of tuna is soaked separately, so it can mature quickly. The immersion time is only a few minutes. The idea is to marinate just enough so that the tuna’s aroma remains and the soy sauce doesn’t overtake it.
On the other hand, the old Edo-style method is to perform Zuke after parboiling.
Parboiling means to wrap the fish in a wet cloth, and poor boiling water on the wrapping until the color of the tuna changes color, then turn the fish over and repeat the process. The fish is then put in ice water so the heat doesn’t go too deep in the meat. It is immediately removed once it cools so that it doesn’t get too watery. The tuna is then put in Zuke soy sauce and left to marinate for about half a day. In this method, the soy sauce only soaks into the surface part where the color changed from the parboiling, so the flavor of the tuna remains.
Both methods keep the maximum tuna flavor possible. Tuna is an essential part of Edo-style sushi. There is great diversity between sushi restaurants in the parts, marinating time and flavor of Zuke, which creates a new, original flavor when the lean meat of the tuna soaks up the soy sauce. The fattiest cuts of tuna are most popular. The lean meat has only become more popular due to a rekindled interest in zuke, but in fact during the peak of the bubble economy, there was a time when high-end restaurants in Ginza didn’t know what to do with all their leftover lean tuna meat. It’s almost unbelievable to think of it now.
Using too much soy sauce spoils delicious sushi so make sure to only put a bit of soy sauce in the special dish. Make sure to tilt the sushi to the side and put just a dab on the end of the topping. Gari can be used as a brush to apply soy sauce to sushi rolls since they cannot be tilted. However, there are differing opinions as to whether this is a refined way to eat or not. Many people say it was basically made up by a publishing company. You just need a few drops in the soy sauce cruet. Actually at very fancy establishments the sushi is served with Nikiri so normal soy sauce is never used for dipping.