‘Sake rice is not table rice!’
Good water – Sake rice – Koji mold and yeast – Brewing alcohol
Sake consists of 80% water. The mineral content of the water influences the growth of the Koji mold and yeast. This means that the flavor of the sake will change depending on the water that is used. The water quality will also affect the feeling in the mouth.
Sake rice is especially suitable for making sake. Important is the Shimpaku in it’s core. This is the milky white substance that remains after polishing the rice. The degree of how much the surface is polished away has an important effect on the character of the sake.
KOJI AND YEAST
Koji mold is added to the rice to become Koji rice. The mold converts the rice’s starches into glucoses. The yeast will ferment the glucoses into alcohol. This means that both saccharification and fermentation happen at the same time.
The fermenting mash that will become the undiluted sake is called ‘Moromi’. The moromi determines the character of the sake. Sometimes brewing alcohol is added to bring out aromas in the sake and to sharpen the flavor of it.
Step 1 Polishing the rice
From the moment the sake rice arrives in the brewery it goes to the mill to polish the rice. By polishing the outer layer of each grain, the starchy core comes exposed. The percentage of polishing is always mentioned on the label of the sake bottle. That percentage refers always to the amount remaining after polishing. This is called ‘Seimaibuai‘. The lower the percentage, the more the rice has been polished and the higher the quality of the sake.
Step 2 Washing and soaking the rice
Because of the polishing procedure the rice grain is covered with rice flour. This needs to be washed away. This way the rice gets moistured. This step is strictly timed.
Step 3 Steaming the rice
In this step the rice will be steamed from underneath during 1 hour. The reason why they do this is to change the molecular structure of the rice. It will make it easier to breakdown the starch.
Step 4 Sprinkling the Koji mold spores
In a hot room with wooden (sometimes metal) walls the spread out rice will be sprinkled with Koji mold spores. The mold will grow on the steamed rice and create Koji rice. This takes about 4 days.
Step 5 Making yeast starter
Yeast, Koji rice, steamed rice and water are mixed gently in a small tank. That way Shubo, the mother of the sake, is created. The yeast starter that causes the fermentation.
Step 6 Making the main mash
Now it is time to put all ingredients together in one big brewing tank: water, sake rice, Koji rice and the Shubo (fermentation starter). During 4 days the ingredients will be added 3 times (San dan jikomi). After the third time, the remaining mash, called Momori, is left for fermentation for about 25 days.
Step 7 Pressing
After that brewing process the sake needs to be separated from the remaining rice solids. Those rice solids are called ‘Kasu’. This is done by a pressing machine.
Step 8 Filtering
Now the fine particles need to be moved out of the sake. Often a charcoal filtration is used in this step. Charcoal bits can trap the remaining dead yeast, enzymes and starch. Charcoal is mixed through the sake and then they run it through filters with special filter paper. What remains is clear sake.
Step 9 Pasteurization
- Polishing the rice
- Washing and soaking (moisturing) the rice
- Steaming the rice (1h at 100°C)
- Sprinkling the rice with Koji mold spores to become molded Koji rice.
- Making yeast starter, Shubo
- Brewing: making main mash, Moromi
- Pressing: getting rid of the Kasu