C12 - The Main Fermentation (Moromi) - completed

Question 1

which stage in sake production determine the styles of the sake?

Answer 1

the main fermentation (Moromi)

Question 2

what are the aims of the brewer in moromi?

Answer 2

• avoid problems
• balance of the two parallel processes
• achieve the desired aromas and textures

Question 3

what are the objectives in the 3 different stages of moromi?

Answer 3

1 - avoid contamination

2 - adjust temperature to balance the two parallel processes

3 - ending the fermentation

Question 4

what fermentation temperature range are most of the sake use?

Answer 4

12 - 18C

Question 5

how long does most of sake take for main fermentation?

Answer 5

21 - 28 days

Question 6

what is the alcohol level achieved for most of the sake after main fermentation?

Answer 6

17 - 20% abv

Question 7

what is the residual sugar level of most of the sake after main fermentation?

Answer 7

15 - 25 g/L

Question 8

what is the fermentation temperature range for making ginjo?

Answer 8

10 - 12C

Question 9

how long it takes to make a ginjo?

Answer 9

30 - 35 days

Question 10

what is kasu?

Answer 10

the suspended particles of rice and yeast cells in the alcoholic liquid after fermentation.

Question 11

what are the two key controlling mechanisms to achieve consistency?

Answer 11

• proportion and timing of adding the ingredients
• temperature, speed and time

Question 12

what is the standard ratio of: steamed rice: koji: water?

Answer 12

80: 20: 130

Question 13

why cannot add all ingredient in one go in the main fermentation?

Answer 13

• the yeast population will be too diluted
• amounts of conversion enzymes will be insufficient
• risk of microbial contamination

Question 14

what level is the koji in the shubo and the earlier additions?

Answer 14

high

Question 15

why the shubo and earlier addition has a high level of koji?

Answer 15

to help the fermentation with a strong start

Question 16

why can’t just add lactic acid to the main fermentation to reduce risk of microbial contamination?

Answer 16

that needs a large amount of lactic acid, which will make the sake too acidic

Question 17

is the sandan jikomi a legal requirement?

Answer 17

No

Question 18

In the Day 1 of sandan jikomi, how many ingredient is added including the shubo?

Answer 18

1/6 of the total volume

Question 19

what is the fermentation temperature in the first day of sandan jikomi?

Answer 19

12 - 15C

Question 20

what is “Odori” mean in Japanese?

Answer 20

dance

Question 21

why it’s nothing to add in the day 2 (odori)?

Answer 21

• give time for the yeast to multiply.
• required for a balanced fermentation

Question 22

what ingredients are added in the day 3 (naka-zoe)?

Answer 22

water, koji, steamed rice

Question 23

how many ingredient is added in day 3?

Answer 23

2/6

Question 24

during the middle addition (naka-zoe) and final additions (tome-zoe), the temperature is reduced to which range?

Answer 24

6 - 10C

Question 25

how brewer lower the temperature in the 3rd addition?

Answer 25

replace some water with ice

Question 26

what does the brewer need to be accurate when building the fermentation?

Answer 26

must be very accurate in the amount and type of koji i.e. ratios of the ingredients

Question 27

how temperature affect both enzymes and yeast activities?

Answer 27

- warmer > more active - cooler > less active - warmer: enzymes increase rate is slower than yeast consume sugar

Question 28

how temperature affect the quantity of enzyme needed?

Answer 28

- warmer: 16 - 18C, more enzymes is needed to keep up with the demand of yeast - cooler: 8 - 12C, less enzymes is needed

Question 29

what will happen if the sugar concentration in the ferment is too high?

Answer 29

- inhibit further starch conversion - result in a higher kasu ratio - unpleasant volatile acidity

Question 30

in the case of sugar concentration is too high in a ferment, what's the consequence of adding water to dilute the sweetness?

Answer 30

- excess water will lead to dilute, flat taste - low density of yeast will let to slow or fermentation stop prematurely

Question 31

what will happen if fermentation speed is far ahead of the starch to sugar conversion?

Answer 31

- sugar level is reduced - the conversion of protein to amino acids and peptides slow down - the resulted sake will have a thin taste and low umami

Question 32

techniques used to controlling temperature:

Answer 32

- using mats (formed or woven) wrap around the tank - insert ice to into the space between the mat and the tank for cooling - modern breweries use jackets on the outside of the tank - heat exchangers submerged into the fermentation mass - computer system controlled water circulation in the heat exchangers

Question 33

besides the techniques, what else is needed to control the temperature closely?

Answer 33

- constant attention - small adjustment

Question 34

to make a rich junmai style sake, what should be the temperature range?

Answer 34

top end of the range, 16 - 18C

Question 35

to make a daiginjo style sake, what should be the temperature range?

Answer 35

lower end 10 - 12C

Question 36

what happen if the temperature is wrong for the desired style of sake?

Answer 36

- impossible to create the desired style - because the desired aromas and flavours are not created

Question 37

when will the brewer decide to end the fermentation?

Answer 37

when the target level of sugar and alcohol are achieved

Question 38

why brewers lower the temperature when it's near the end?

Answer 38

- because high temperature and/or high alcohol concentration will increase the rate of dying yeast - which will create undesirable tastes and aromas in the sake

Question 39

what ingredients and conditions should be used for making a rich, high-umami style?

Answer 39

- high polished ratio (70%+) - so-haze koji - higher fermentation temperature

Question 40

what is the result of using high polished ratio rice, so-haze koji and high fermentation temperature?

Answer 40

- higher level of protein being broken down to amino acid and peptides - fast starch to sugar conversion to feed the yeast - vigorous fermentation - higher acidity, low aroma - richer tastes

Question 41

what ingredients and conditions should be used for making a ginjo style?

Answer 41

- low polishing ratio rice (<60%) - use tsuki-haze koji - extremely cool conditions - fermentation temperate of 8 - 12C - long fermentation time 30 - 35 days

Question 42

what is the result of using low polished ratio rice, tsuki-haze koji and low fermentation temperature?

Answer 42

- tsuki-haze convert the starch to sugar slowly, as well as amino acid nutrients - yeast growth is limited - fermentation is slow - acidity is low - low degradation of proteins - result is a light and smooth taste and texture - aromatic

Question 43

why ferment in low temperature produce a more aromatic sake?

Answer 43

- because low temperature reduced the lost of esters by evaporation

Question 44

under what condition yeast will create increased levels of a particular group of higher alcohols?

Answer 44

- cold temperature - shortage of nitrogen (or amino acid)

Question 45

what kind of higher alcohol will yeast number 9 create under extreme stress?

Answer 45

isoamyl alcohol

Question 46

what is ester?

Answer 46

the highly fruity or aromatic compounds produced by yeast when under stress

Question 47

how yeast produce esters?

Answer 47

- in the enzymatic chemical reactions - yeast combine various alcohols with acetyl, caproyl-coA and other chemical groups to produce esters

Question 48

what are the most notable esters in ginjo?

Answer 48

- isoamyl acetate (aromas of banana) - ethyl caproate (aromas of green apple or melon)

Question 49

what is the ideal temperature tolerance per day for ginjo fermentation?

Answer 49

0.3 - 0.5C

Question 50

why it is important to keep monitoring the ginjo fermentation?

Answer 50

- if yeast nutrients is too high, the fermentation will run too fast. - it's difficult to lower the temperature because it's already in the lowest limit of yeast

Question 51

after a long fermentation at low temperature, what is the result in the remaining rice solid?

Answer 51

- rice does not broken up as much - many rice solid remaining in the tank

Question 52

why leaving a lots of rice solid (kasu) in the tank is a good sign of quality for ginjo?

Answer 52

- that means very little amino acid or organic acids are extracted - which create a very smooth texture and clean, delicate taste

Question 53

What is the ideal fermentation batch size (rice and water) range of brewing ginjo?

Answer 53

600kg - 1500kg of polished rice 800 - 2000 L of water

Question 54

How many liters of ginjo sake can be produced by 600 - 1500 kg of polished rice plus 800 - 2000 L of water?

Answer 54

720 - 1800 L. of sake

Question 55

how many junmai ginjo can be produced by 1 kg of polished rice?

Answer 55

about 2.5 L. - after water adjustment to 15% abv.

Question 56

how many junmai can be produced by 1 kg of polished rice?

Answer 56

about 2.6 L.

Question 57

why the yield of honjozo is higher than junmai?

Answer 57

due to the small amount of jozo addition.

Question 58

how many futsu-shu can be produced by 1 kg of polished rice?

Answer 58

about 5 L

Question 59

why futsu-shu can have a much higher yield?

Answer 59

- more dissolved rice - higher level of extraction at the filtration stage - up to 50% of jozo alcohol addition

Question 60

typically what is the fermentation batch size of futsu-shu compare with junmai?

Answer 60

futsu-shu is 20 - 30 times bigger than junmai

Question 61

why futsu-shu ferment in such large size?

Answer 61

to lower the production cost.