Rice it is the main ingredient in sake. In a previous post I talked about different types of sake rice. If you missed or want to revisit you can click here.
The first steps in brewing sake is preparing rice. This rice will be used to make the koji rice and will also be fuel that the koji and yeast breakdown into sugar and then into alcohol. The following post discusses the first step in brewing sake and all have to do with the rice.
The first step in getting the rice ready is polishing the rice. Polishing rice happens by running the rice grains between two rough surfaces over and over for a few hours. Each pass between the surfaces removes just a little of the outside layers of the rice. This is done until the rice reaches its appropriate seimaibuai (also known as its Rice Polishing Rate).
The seimaibuai number is listed as the percentage of the rice grain remaining after polishing. So if you see a sake with a RPR of 60% it means they polished off the outer 40% and the grain has 60% remaining. The different styles have different RPR requirements.
Here are the different grades broken down by RPR (seimaibuai)
The rice has been polished to the toji’s (master brewer) requirements it is on to the second step. It is time to wash the rice. This step is self-explanatory. The kurabito (employees of the sake brewery) wash the sake to remove the dust left over from the polishing process.
The third step is soaking the rice. This step allows the rice to absorb some water and become softer. This step heavily relies on the toji’s experience. He determines how long it should soak using his experience.
The fourth step is steaming the rice. They take the soaked rice and put it in a steamer. Now, you might be thinking it like at home where they heat the rice in the water. That is not the case here. The rice is loaded into an open pot called a koshiki. The koshiki is the covered with a sheet and steam it sent up from the bottom. The steam rises up through the rice and around the rice until the rice is done. The point of this is to soften the rice to the core to allow for the koji to get to the center of the grain (shinpaku) where most of the starch in concentrated and break it down from starch to sugar.
These steps are what get the rice ready to make koji, fermentation starter, and main mash. I will cover those other topics in future posts.