― From the Science of Taste, Culinary Techniques, and Cultural Background ―
Why do soy sauce and wasabi alone complete the flavor of sushi? It is because the umami and aroma of the seafood, the acidity of the vinegared rice, the chef’s skill, and the values of Japan’s unique food culture all unite, come together harmoniously in the mouth.
The umami components in seafood, such as glutamic acid, inosinic acid, and succinic acid, combine with the acetic acid in the vinegared rice and the amino acids in the soy sauce to create a deep flavor. Soy sauce integrates these umami flavors, and its fermented aromatic components (phenols and furanones) blend with the natural aroma of the seafood to add depth to the flavor. Salt tightens the flavor profile by assisting taste receptors, balancing the overall composition alongside the vinegar rice’s acidity.
Furthermore, the pungent compound allyl isothiocyanate in wasabi is also perceived as an aroma in the nasal cavity, uniting spiciness and fragrance to further enhance the multidimensional taste experience.
The unsaturated fatty acids (EPA and DHA) contained in fish fat oxidize slightly to produce volatile components such as hexanal, which are perceived as the “aroma of the sea.” These aromas are released most naturally at room or body temperature. The acidity of the vinegared rice melts in the mouth and enhances the aroma, bringing out the maximum umami of the fish topping and creating a scientifically sound harmony of flavors.
The artisan’s skill exists to further enhance this chemical interaction. They perform preparatory steps tailored to the freshness and condition of each topping, removing excess moisture and off-odor to highlight the ingredient’s inherent umami. Cutting techniques are also meticulously chosen for each topping—such as sogigiri (angled slicing), hikkikiri (pulling cut), or hirazukuri (flat slicing)—considering the fish’s fiber and fat distribution to adjust texture and aroma release.
The temperature and firmness of the shari (vinegared rice) are precisely calculated to ensure the fish’s fat melts perfectly in the mouth, creating the moment where aroma and umami unite. Wasabi is meticulously adjusted in quantity and placement for each piece to accentuate its fragrance and balance the mouthfeel. The combination of all these elements creates a single, complete taste experience in the mouth.
And cultural background underpins this harmony. This refers to a culinary philosophy that highlights the inherent appeal of ingredients by subtracting unnecessary elements rather than adding excessive flavors or aromas. For example, instead of drenching fatty white fish in strong sauce, it is designed so that the fish’s natural umami and aroma can be felt in a single bite, simply seasoned with the spiciness of wasabi and the saltiness of soy sauce. Whereas Western cuisine is often described as “additive cooking,” building flavor through layers of seasonings and sauces, sushi emphasizes the natural flavors of ingredients through subtraction.
The umami of the fish, the flavor of its fat, the acidity of the rice, and the aroma of the wasabi are calculated to harmonize naturally. In the early Edo period, wasabi was expensive and not something commoners could use daily. However, during the late Edo period, as “hayazushi” (sushi using vinegared rice to shorten fermentation time) became popular at street stalls, artisans noticed that wasabi’s spiciness and aroma enhanced the flavor of raw fish. They gradually began incorporating it into sushi. Thus, artisans continued refining their craft to complete each piece with minimal adjustments while respecting the individuality of the ingredients, establishing the philosophy of harmonious flavors in sushi.
Thus, sushi is perfectly complete with just soy sauce and wasabi. The fusion of scientific umami synergy, the artisan’s meticulous technique, and the cultural backdrop of the subtractive aesthetic allows one to experience the depth of flavor and the three-dimensionality of aroma in a single bite. Soy sauce and wasabi are not mere seasonings; they embody the essence of sushi.