Sake Shubo and Moromi

Question 1

Why is the shubo created before the moromi?

Answer 1

To create an acidic environment where the yeast can multiply healthily

Question 2

How long is the shubo fermentation?

Answer 2

14 - 28 days, depending on the method

Question 3

What is the bucket-like tool used to control the temperature of the shubo ferment?

Answer 3

Daki

Question 4

What is a daki?

Answer 4

A bucket-like tool that can be filled with hot or iced water and used to cool or warm a shubo ferment.
Alternatively pipes, jackets and temperature controlled tanks can be used to control temperature.

Question 5

What are the three methods for making the shubo?

Answer 5

sokujō-moto
Kimoto
Yamahai

Question 6

At what temperature is the sokujō-moto fermented?

Answer 6

20-25°C

Question 7

At what temperature is the kimoto fermented?

Answer 7

6-7°C

Question 8

Why was the sokujō-moto method preferred to kimoto?

Answer 8

• Faster (14 days instead of 28 days)
• Easier to control (particularly acidity level)
• No reliance on bacteria (less risk of ferment contamination)
• Pure flavour profile with less umami

Question 9

What is fast-sokujō?

Also called medium temperature sokujō.

Answer 9

A sokujō fermented at a higher temperature to extract enzymes even more rapidly. The fermentation time takes only 10 days instead of 14.

Question 10

Where was the kimoto method developed?

Answer 10

Nada in Hyogo Prefecture

Question 11

How is the yamahai method different to the kimoto method?

Answer 11

Kimoto - rice and kōji are pounded (time consuming and laborious) to create a large surface area for lactic bacteria to develop at low temperature (6-7°C). The temperature rises slowly and after 14 days it is inoculated with yeast and fermented for 14 days further.

Yamahai was developed in 1909. Kōji and water are mixed to extract enzymes, then steamed rice added. Lactic acid is also relied upon for 14 days, yeast added and fermented 14 days further. Much less labour as there is no pounding.

Question 12

What are the benefits of yamahai or kimoto?

Answer 12

• microbial populations present whilst the lactic acid is developing creates interesting flavours and more complexity
• richer flavours than sokujō
• higher acidity than sokujō
• if the shubo is deliberately exposed to oxygen, oxidative flavours can develop that complement the umami and acidity of the yamahai style in particular

Question 13

What is kō-on tōka?

Answer 13

A new method of shubo.
Very high temperatures early on to sterilise the mixture and accelerate the breakdown of starches.
Especially used in warm brewing areas and for very pure, clean ginjō.

Question 14

Which shubo technique uses very high temperatures early on to sterilise the mixture and accelerate the breakdown of starches?

Answer 14

Kō-on tōka

Question 15

What is bodai-moto?

Answer 15

An ancient four step shubo technique that uses sour rice water to play the role of the lactic acid in the shubo.

Question 16

What affect will the use of black or white kōji have on the ferment?

Answer 16

Higher levels of acid, particularly citric. This can be used to maintain a healthy ferment.
Black and white kōji can also be used if the brewer wants to avoid using a shubo at all

Question 17

What is the ratio of the moromi?

Answer 17

80 parts steamed white rice
20 parts kōji
130 parts water

Question 18

What is the temperature of the moromi on Day 1 (hatsu-zoe)?

Answer 18

12-15°C

Question 19

What happens on Day 2 (odori) of the moromi?

Answer 19

Nothing - yeast is allowed to multiply.

Temperature rises slightly

Question 20

Why is the three stage addition made to the moromi? What does the brewer want to achieve?

Answer 20

• ensure that the yeast population doesn’t get too diluted
• ensure that there are sufficient quantities of conversion enzymes
• avoid the risk of microbial spoilage

Question 21

What is the temperature of the moromi on days 3 and 4?

Answer 21

6-10°C

Question 22

What happens if the main ferment’s alcoholic fermentation lags behind the sugar conversion rate? How can this happen?

Answer 22

The sake will become too sweet. At high sugar levels the sugar to starch conversion becomes inefficient and can lead to volatile acidity or excess sake-kasu.

This can occur if there are too many enzymes in relation to the yeast population. This can be controlled by temperature, or at last resort, the addition of water.

Question 23

What happens if the main ferment’s alcoholic fermentation speeds ahead of the sugar conversion rate? How can this happen?

Answer 23

The reduced sugar levels will be a limit on fermentation. The yeast will slow. Amino acid and peptide conversions will also slow, and the sake will have a thin taste and low umami.

Question 24

What is the temperature of a junmai ferment?

Answer 24

16-18°C

Question 25

What is the temperature of a daiginjō ferment?

Answer 25

8-12°C

As low as 6°C

Question 26

How is the main ferment ended? Why?

Answer 26

The temperature is lowered.

If the ferment is allowed to stop naturally, off-aromas can be caused due to a lack of yeast nutrition and yeast stress.

Question 27

Why are higher polishing rates (70% and higher), sō-haze kōji and higher ferment temperatures suited to junmai and futsū-shu?

Answer 27

• high polishing ratio means more protein, which means a higher level of umami
• sō-haze kōji means more enzymes, which are needed for a fast and vigorous fermentation
• higher temperatures mean a more efficient fermentation and a low sake-kasu ratio

Question 28

How many days does a ginjō fermentation take?

Answer 28

30-35 days

Question 29

Why are cool temperature fermentations used for ginjō style sake?

Answer 29

• tsuki-haze kōji releases enzymes more slowly
• limited release of sugar, yeast growth and low protein conversion lead to a lighter taste and texture
• desirable esters (ginjō-ka) are created and retained
• the rice doesn’t break up as much at low temperatures. so there are lower levels of amino and organic acids

Question 30

How much polished rice is required to make 2.5L of junmai ginjō?

Answer 30

1 kilogram

Question 31

How much junmai ginjō can be produced from 1kg of polished rice?

Answer 31

2.5 litres

Question 32

How much polished rice is required to make 5L of futsū-shu?

Answer 32

1 kilogram

Question 33

How much futsū-shu can be produced from 1kg of polished rice?

Answer 33

5 litres - because of the more complete rice dissolving, the higher level of extraction at filtration and the addition of jōzō.