Sushi soy sauce and regular soy sauce

Chinese Soy Sauce: Soybean Residue + Wheat Bran: The traditional method of making Chinese soy sauce uses soybean residue and wheat. However, in the 1950s, in order to save costs, wheat bran began to be used in large quantities as a substitute. This increased the yield, but the color of the soy sauce became lighter, and the flavor became thinner.

In Chinese soy sauce, most add bran, while Japanese sushi soy sauce adds wheat.

Chinese soy sauce: soybean residue + bran: the traditional method of making Chinese soy sauce uses soybean residue and wheat. However, in the 1950s, in order to save costs, bran began to be used in large quantities as a substitute. This increased production, but the color of the soy sauce became lighter, and the flavor became thinner.  

Japanese sushi soy sauce: soybean residue + wheat: the method of making Japanese soy sauce was introduced from China, so it also follows the formula of soybean residue and wheat, and it still does so today. Wheat, when roasted, emits a fragrance that adds flavor to the soy sauce, making it rich. There was a time when Japan faced material shortages, so bran was used instead of wheat to brew soy sauce, but soon wheat was used again.

2. China uses low-salt solid-state fermentation, while Japanese sushi soy sauce uses high-salt liquid-state fermentation 

China: low-salt solid-state fermentation: the concentration of the brine added is low and the amount is small, resulting in solid-state fermentation of the soy mash, with a short production cycle that can be completed within a month. Traditional Chinese soy sauce making emphasizes "spring starter, summer sauce, autumn oil," where a barrel of sauce needs to undergo at least six months of fermentation before the first soy sauce can be drawn. However, the current method has greatly shortened the time, and various microorganisms cannot grow abundantly, resulting in a significant reduction in flavor.  

Japan: high-salt liquid-state fermentation: the concentration of the brine added is high and the amount is large, resulting in liquid-state fermentation of the soy mash. Soy sauce made this way has a rich and fragrant flavor and good quality. Nowadays, Japanese soy sauce production often involves precise control of details, with a long production cycle to ensure high-quality and stable output.