02: Sake is made from mold. Really!?

Writer: Tamaki Kashiwagi

In my last column, I explained the origin of Sake. It was made from rice chewed in a mouth,  spitted back into a barrel. It looked like thick mud, rather than liquid as we know Sake to date. So the ancient people ate Sake with chopsticks, not drank it. A bit disgusting, isn’t it? Then when did we start “drinking” Sake?


We don’t know exactly, but it is believed to be during the Nara period (710-794) because some cups and flasks for drinking Sake were found from old ruins of the Nara period. They are similar to the one that we are serving Sake for today. And there is an interesting description in the “Kojiki”, the Japanese oldest written record of ancient history of Japan scripted in the VIII century. It says that “koji” was introduced to the Sake making in the Nara period, the method of which invented in China. Because of the coincided timing, it is believed that “koji” is something to do with the transformation of solid Sake to liquid.


So what is “koji”? It is steamed rice covered by molds. It is made by sprinkling “koji bacteria” (scientific name: Aspergillus)” over steamed rice so that the molds grow on rice. Until today, the same method is used. Sake is made from ”koji”, additional rice and water. You might think that Sake contains molds. Yuck! But don’t you worry. It doesn’t contain molds. We are just getting their help for making Sake. Generally, alcohol is made through fermenting sugar. But rice does not have enough sugar unlike grapes. “Koji” has the power of decomposing rice starch and converting it into sugar. So after putting koji into rice, enough sugar is generated for alcohol production.


There are two types of molds, “useful” and “harmful”. “Koji” is obviously the former. This useful mold is used also for making miso, soy sauce and cheese. In the VIII century during the Nara period, the biology was not advanced as today, so I wonder how the ancient people distinguished the useful molds from harmful molds. There might have been great sacrifices for discovering “koji”. The people might have eaten and got a lot of diarrheas! They might have died because of it!? We must be grateful for those great ancestors who gave us wonderful drink!