What is "Fermentation"?



Q1. Tell me about the fermentation process in everyday foods and drinks such as sake, wine, beer, miso, soy sauce, vinegar, mirin, natto, bread, cheese, kimchi pickles, yoghurt, fermented plants extract “Enzyme”, etc.


  1. The main ingredients involved in the process are sugar and bacteria (yeast bacteria). Bacteria consume sugar and produce beneficial substances such as amino acids, oligosaccharide, vitamins, etc.


Let’s look at Japanese sake.  It’s made from rice which contains starch.  Starch forms long chains made up of sugar.  So rice malt is needed to break the chains down into small sections of sugar which the yeast bacteria are then able to consume.

The bacteria in turn produces beneficial substances such as amino acids, oligosaccharide, lactic acids, vitamin, etc. for human.

If the process continues for long enough, alcohol and carbon dioxide are produced.

This is the process of alcohol fermentation.


In the case of miso, the soy beans contain chains of both proteins, such as amino acid, and sugars.

The malt used breaks down these long chains and yeast bacteria consumes the amino acids and sugar and produces amino acids,,,,,etc. 

*Did you know?

“Koji” is a fungus which converts the starch in rice or soybeans into glucose.

 Now let’s look at fermented plants extract: the products name is known as “Enzyme”.

Fermented plants extract is mainly ingredients is vegetables, fruits, grain and beans, and seaweed.

Leaf vegetables and seaweed contain many vitamins and minerals, but little sugar or protein.  However, they contain lots of fibre which can be broken down into sugar and this is consumed by yeast bacteria.

Root vegetables, such as spinach, etc. contain lots of sugar, so it is easy for the bacteria to consume it.

Fruit, such as unpeeled apples, contain fructose, a sugar, and lots of fibre, so they are easily fermented by yeast bacteria, just as the grapes used in making wine.