Hi, I'm C-taka.
Rice and water are typical ingredients of sake, but in fact, rice and water alone cannot produce sake.
Because in order to make rice into sake,
(1) Saccharification to convert starch in rice into sugar
(2) Fermentation to change the sugar into alcohol You have to go through these two steps.
In each of these stages, small microorganisms such as aspergillus and yeast are active.
Now, let's check the functions of Aspergillus oryzae and yeast.
Aspergillus oryzae produces sugar, which is essential for fermentation.
First, aspergillus oryzae is a microorganism essential for saccharification.
Aspergillus oryzae is a kind of mold, and there are several types of aspergillus used in Japan. White koji, black koji and yellow koji are usually used for shochu, black koji for awamori, and yellow koji for sake as well as miso and soy sauce.
Aspergillus oryzae is sprinkled on steamed rice and multiplied to produce koji(rice molt). In addition to saccharification, Aspergillus oryzae also converts proteins into amino acids to produce umami and flavor components.
In sake brewing, microbial yeast is responsible for alcohol fermentation. The role of yeast is to ferment so well.
And yeast is an essential microorganism for fermentation.
The first requirement for yeast is to ferment vigorously and soundly. Generally, yeast has a property of producing a good aroma to the extent that it is placed in a severe environment at a low temperature, but if it cannot stand the environment, it may produce unpleasant taste or stop fermentation.
For this reason, for sake brewing, it has long been practiced to isolate and culture superior yeast from moromi (unrefined sake) produced by breweries that produce good sake and to breed them. A typical example is "Kyokai yeast" selected and distributed by the Brewing Society of Japan.
Yeast also produces acid and flavor components during fermentation. In recent years, as a result of the elucidation that yeast has a great influence on taste and flavor, original yeasts have been cultivated and used not only in the National Research Institute of Brewing and the Brewing Society of Japan, which had been in charge of the research of yeast, but also in prefectures and sake breweries.
Below are some of my previous posts on sake ingredients.
ctaka-japanese-sake.hatenablog.com
