Since sushi has become introduced to American in the late 1960s it has moved increasingly further from the way it was traditionally made in Japan.
Modern sushi has a lot of sugar that is being added frequently to the sushi rice. It is common for many recipes to include as much as 1 tablespoon of sugar for every cup of sushi rice that is going to be used for making sushi rolls.
In this manner for 20 sushi rolls that would amount to around 10 tablespoons of sugar. Keep in mind that even for Coca Cola the amount of sugar is only just 44 grams. So 20 tablespoons of sugar would equal the amount of sugar consumed by drinking about 3 cans of Cola.
Considering this fact, eating sushi might not be as healthy as you think. Since many Americans including myself eat an embarrassing amount of sushi rolls in one setting.
How Much Sugar Was Added In Traditional Sushi?
The answer is none, because in the beginning there was no addition of sugar to sushi rolls.
According to this source, the use of sushi rice was only for fermenting the fish. The innovative idea of adding vinegar to sushi rice didn’t come about until the middle of the 17th century.
Moreover, it was not until the 18th century in Japan did people start consuming sushi rice along with the sashimi(sushi fish).
But the reason sushi rice tastes differently is not due to the added sugar. Instead the boost of flavor comes from the sourness from fermenting with the rice vinegar.
It is also not necessary to add sugar to the sushi rice. As many people who cook at home can feel free to omit the usage of sugar to the process altogether. Since it will taste just fine without added sugar.
Traditionally in making sushi rice sugar is not frequently added, because the point of using sugar was to balance out the sourness of the vinegar. So a tiny pinch of sugar is good enough to offset the sour flavour from the vinegar.
Moreover, sushi is made with the use of Japanese short grain rice. What makes this variety different is that it has more firmness and chewiness, also very sticky when cooked. Along with imparting a natural sweet flavor without the need of added sugar.
Despite these factors affecting how often sugar is added there are still great differences throughout Japan. Which is heavily dependable on the chef along with the regional preferences for greater sourness vs. sweetness.
Is Sugar Needed to Ferment Sushi Rice?
Another reason why sugar is not often added to sushi rice is because it is not needed to create that fermented sour taste. The sour taste in foods like yogurt, cheese, and sushi rice comes from fermented lactoseconverted to lactic acid.
It is the simple science of turning soluble carbohydrate into lactic acid(the thing responsible for giving sushi rice the sour flavor).
For those who paid attention in high school chemistry should remember that carbohydrate is a type of fast energy source(sugar).
Why is this important? Because rice is mainly carbs, so it is already composed of glucose. That’s why it is unnecessary to add sugar to the fermentation of sushi rice.
The use of rice vinegar is the thing that helps ferment the Japanese short rice and gives it that sour after-taste. Additionally it has the benefit of killing the growth of bacterias.
In the early traditions of sushi making people didn’t add rice vinegar or sugar to the fermentation of rice.
Hence, without vinegar the process that allows the rice to produce lactic acid for pickling the sushi fish could take from 2 months to more than a year.
Also due to this long time-consuming process the rice would be very smelly, so people would throw the rice out and only eat the pickled fish.
Then during the middle of the Edo period, a doctor known as Matsumoto Yoshichi revolutionized the process by introducing the idea of adding vinegar to the sushi rice. This way the fermentation process was much faster and gave the sushi rice a refreshing taste.