Production method (Saké)
Let’s learn about the production method (Saké) to make your cup of Saké more tasteful.
Although the production process of Saké is extremely complicated, its basis is relatively simple.
There is an old saying about production method (Saké) :
“First the Koji, and then the Moto, and finally the Tsukuri (Tsukuri means the Saké manufacturing method as a whole)”.
1) Moto (mother of Saké)
Let’s start with Moto.
First of all, you must prepare the Koji as well as all other fermented foods I’m introducing. As I mentioned in the page of Koji, Koji bacteria convert starch into glucose which is indispensable to produce alcohol. This is the first step of fermentation.
In this Koji, you add cooked rice and water to make Moto, i.e. “mother of Saké”. The purpose of this process is to multiply Koji-bacteria and Saké yeast, expelling other bacteria.
In the Moto, the below are in activity:
ii) lactic acid bacteria,
ⅳ) Saké yeast
At an early stage, i) nitrobacter derived from rice or water are active. It reduces the nitrate in the water to nitric acid that attacks other bacteria.
However, when the temperature rises *, ii)lactic acid bacteria multiply.
It produces lactic acid which expels other bacteria, including i) nitrobacter. But both iii) Koji-bacteria and ⅳ) Saké yeast are resistant to lactic acid.
Subsequently, when i) nitrobacter is extinguished, Saké yeast is added into Moto to ferment glucose produced by Koji-bacteria into alcohol.
* Actually, the lactic acid bacteria do not multiply only by increasing the temperature. Therefore it requires some human-induced methods to reproduce them, e.g. a: Kimoto,
As for this process I’d like to explain later.
Thus two processes of fermentation advance in the Moto:
i) fermentation to get glucose,
ii) fermentation to get alcohol.
Such a simultaneous fermentation is quite unique.
In this connection, wine is produced by one process.
Because the wild yeast living in the skin of grapes ferments the glucose in grapes to alcohol. In addition, there is no need to multiply the yeast.
Saké is a drink with the highest alcohol content in the world. Many might say that whiskey or vodka contains more alcohol. But these percentages are earned after having distilled.
Surprisingly, the highest alcohol content of Saké is 23%. (It’s a little too strong for Saké and sometimes they mix it with water. Therefore, alcohol content of Saké is generally from 15% to 20%).
Why can Saké contain so much alcohol?
As always, the reason is in Koji.
In general, yeast dies because of the alcohol which it made by itself (Lactic acid bacteria also die because of the alcohol).
But the yeast of Koji-bacteria (Saké yeast) does not die thanks to lipid protein that protects it against alcohol. Of course, it is Koji-bacteria that produce this protein.
In the next step, you add more cooked rice, Kojiand water to make Moromi.
But you have to added them little by little, generally in three times, to avoid weakening yeast activities. Thus, the scale of fermentation gradually increases (this process is called as kaké).
After the fermentation of a month, you can gain 14 times more of Moromi.
Apropos, Moromi is a cloudy fluid.
By filtering the lees, it becomes clear.
Seisyu (clear sake)
Nigori-saké (whitened Saké. Nigori means turbidity) is Saké without enough filtering.
Actually, it is more nutritious than the clear Saké (“sei-shu”).
3) Kimoto, Yamahai, Sokujyô
These are the methods to effectively reproduce lactic acid bacteria.
In this method, Lactic bacteria naturally multiply by pounding cooked rice in the flat bucket to make Koji adhere to the whole rice. But this operation called “yama-oroshi” (“yama” means a mountain) requires a mastery difficult to learn. So in the early 20th century when the Sakéfermentation system was scientifically elucidated, simpler methods were invented.
They are b: yama-hai and c: sokujyô.
In this method, you add Koji dissolved in water to cooked rice and make the rice absorb the Koji enzyme in the water. This is “Yama-hai” which literally means the abolition of “yama”. Because this method can save the effort of “yama-oroshi”. However the cohesion between rice and Koji is lighter than in a) Kimoto.
In this method, you add the separately cultured lactic acid.
By this method, it only takes about 14 days to do Moto, although it takes about 30 days in the ways a) and b).
This is the final process of production method (Saké).
In this process, the clear Saké (“sei-shu“) is heated to 65°C to stop enzyme activities and sterilize Saké.
In general, “hi-ire” is done twice:
1) after being filtered,
2) just before shipping for sale.
But only 1) or 2) are also possible. From time to time, you can pass over the process of “hi-ire” itself.
In this case, the yeast is still active and you can taste strong “umami” flavor, although it can change rapidly in quality.