In the earlier article, I explained Single Fermentation and Multiple Fermentation. Here, I will focus on Multiple Fermentation and explain the differences between beer and sake fermentation.
There are two types of multiple fermentation: Sequential Multiple Fermentation (Single Line Multiple Fermentation) and Multiple Parallel Fermentation.
Sequential Multiple Fermentation (Single Line Multiple Fermentation): Beer
In beer brewing, saccharification and alcohol fermentation happen separately. Since malt for beer has enzymes to break down starch into glucose (sugar) by keeping it in a certain temperature of water at around 65 degrees celsius, brewers provoke saccharification in a tank A to extract the malt glucose. After the saccharification, they cool them down and add yeast to the juice and begin alcohol fermentation in a tank B. There are types of beer made from barley, rice, corn, and other starch; however, the process is the same as above.
Multiple Parallel Fermentation: Sake
Unlike malt for beer, rice for sake doesn’t contain enzymes in itself.Therefore, in sake fermentation, brewers need koji enzymes to help transfer the starch of rice grains to glucose. After they make koji rice, they add the koji rice, steamed rice, and yeast to a tank. As normal steamed rice contains starch, enzymes continue provoking saccharification by koji enzymes while producing alcohol fermentation by the yeast simultaneously.
By learning the kinds of multiple fermentation, we can understand sake has the most complex process in alcohol brewing globally. It is what embodies Japanese craftsmanship.
As for the science of koji mold, I will dig into the details in article number 9.
Before moving on to the details, let your curiosity grow about the whole sake brewing process.