C10 - Water and yeast - completed

Question 1

Which two ingredients of sake are not derived from rice?

Answer 1

Water and yeast

Question 2

Over 80% of the sake is made up of what?

Answer 2

water

Question 3

Besides alcohol, what else does yeast create during fermentation?

Answer 3

many of the signature aromas

Question 4

Why historically breweries are located near water source?

Answer 4

• water made up over 80% of the sake
• sake production needs a lots of water for: making the sake, cleaning…etc.

Question 5

what are the two major source of water for most of the breweries?

Answer 5

• subsoil
• tap water

Question 6

can brewer alter the content of the water?

Answer 6

yes, can filter and alter the mineral content, acidity of the water.

Question 7

What is the upper limit in the food product manufacturing standard control?

Answer 7

• level of organic substances
• level of iron

Question 8

how strict is the standard on the max. level of iron in the water for making sake vs. tap water?

Answer 8

• the limit is less than 1/10 of the level permitted in tab water

Question 9

What happen to the sake if iron level of the water is too high?

Answer 9

• it gives the sake a reddish-brown colour
• spoils the aroma and taste

Question 10

Measuring water’s “hardness” and “softness” are determined by which two elements?

Answer 10

• calcium
• magnesium

Question 11

which element is usually the dominant metal in water?

Answer 11

calcium

Question 12

which element is the most important in water for making sake?

Answer 12

magnesium

Question 13

why magnesium in water is more important in making sake?

Answer 13

• it enhance the metabolism of the yeast

Question 14

what are the other two elements in water aid the growth of yeast and koji?

Answer 14

• potassium
• phosphorus

Question 15

what kind of water is once preferred by brewers for fast and stable fermentation?

Answer 15

mineral rich i.e. magnesium, potassium, phosphorus

Question 16

Why mineral rich waters are good for fast and stable fermentation?

Answer 16

the minerals for nutrients for the yeast, which can reduce risks in contamination, weak or starving yeast during fermentation

Question 17

where was the famous mineral-rich water found?

Answer 17

Hyogo prefecture / Kobe / Nada / miya-mizu water

Question 18

what style of sake is produced using the miya-mizu water in Kobe?

Answer 18

more restrained, drier style

Question 19

Where can you find the famous lower mineral water?

Answer 19

Kyoto / Fushimi water

Question 20

what style of sake is produced using the Fushimi water in Kyoto?

Answer 20

softer style

Question 21

Other than water, magnesium, potassium and phosphorus can also be found in which sake ingredient?

Answer 21

rice

Question 22

What is the concern in using the nutrients in rice rather than water to feed the yeast?

Answer 22

• need to be large amount and fast enough to avoid contamination or starving yeast.

Question 23

which koji style should be used when using low mineral water but aim for a vigorous fermentation e.g. the Kyoto style?

Answer 23

so-haze

Question 24

what can the brewer do if the water is low in mineral but want to use tsuki-haze koji to produce ginjo style sake

Answer 24

adjust the mineral content of the water

Question 25

which area makes ginjo style sake using low mineral water and tsuki-haze koji?

Answer 25

Saijo, Hiroshima

Question 26

what are the 3 major output of yeast from brewer's point of view?

Answer 26

- alcohol - aromas - organic compounds e.g. acids

Question 27

Other than aromas, what else does yeast determine the sake's style?

Answer 27

- texture - acidity

Question 28

what are the 3 major acids found in sake?

Answer 28

- lactic acid (by shubo) - malic and succinic acids (by yeast)

Question 29

yeast activity (speed) are controlled by...?

Answer 29

temperature

Question 30

at what temperature range, yeast become inactive?

Answer 30

3 - 5C

Question 31

typically, wine yeasts stop working (dormant) when alcohol level reach ?? %abv?

Answer 31

15 - 16% abv

Question 32

How beer and wine yeast behave differently from sake yeast in high alcohol environment?

Answer 32

- wine and beer yeast will dormant to protect themselves - sake yeast keeps working, produce even more alcohol

Question 33

why yeast doesn't like high alcohol environment?

Answer 33

alcohol is toxic to yeast, it can be killed by strong alcohol.

Question 34

What is the maximum alcohol level yeast can produce in making sake?

Answer 34

22% abv

Question 35

what if the sake has alcohol level over 22% abv?

Answer 35

it cannot be called sake legally

Question 36

traditionally, where do the yeast come from?

Answer 36

ambient brewery yeast - which attached to the surfaces in the brewery

Question 37

what is the problem using ambient brewery yeast?

Answer 37

the result is unpredictable, depends on which yeast strain complete the fermentation

Question 38

what made sake yeast behave not the same as wine and beer yeast?

Answer 38

mutation

Question 39

initially, how brewers propagate and re-use yeast?

Answer 39

they take the yeast from the foam of a successful fermentation and inoculate in the next fermentation

Question 40

what are the problems of propagate yeast from the former fermentation?

Answer 40

- flavour production is inconsistant - population of yeast may changed when reused - it contains many strains of yeast and the ratio changes in the next fermentation

Question 41

what caused the flavour production inconsistent when propagate the yeast?

Answer 41

- microbial contamination

Question 42

How brewing science improved the consistency of yeast?

Answer 42

- it can isolate individual strains of yeast - avoid mutation in propagation

Question 43

why brewers now rely on suppliers in sourcing yeast?

Answer 43

because isolating and maintaining strains of yeast is a specialised skill

Question 44

where brewers buy their yeast from?

Answer 44

Brewing Society of Japan (BS)

Question 45

since when, Brewing Society of Japan start distribute selected yeast widely?

Answer 45

1906

Question 46

What is the main action the Brewing Society of Japan does to yeast?

Answer 46

- Brewing Society of Japan manages the multiplication of yeast - number and pack the yeast in ampules to avoid contamination

Question 47

where were the Brewing Society of Japan yeasts found?

Answer 47

- first isolated by a particular brewery - improvement on earlier numbered yeasts - developed by other organisations i.e. regional research institute or tax bureau

Question 48

which year did Brewing Society of Japan Yeast "Number 1" released?

Answer 48

1916

Question 49

which year did Brewing Society of Japan Yeast "Number 8" released?

Answer 49

1963

Question 50

Which brewery isolated BS Yeast "Number 6"? In which year?

Answer 50

Aramasa brewery in 1935

Question 51

Which brewery isolated Brewing Society of Japan Yeast "Number 7"? In which year?

Answer 51

Miyasaka brewery in 1946

Question 52

what is the top priority of the yeast quality?

Answer 52

a successful, complete fermentation

Question 53

why a successful, complete fermentation is important to both the brewery and the government?

Answer 53

- the brewer don't want to lose the whole batch of production - sake is a big proportion of tax revenue to the government

Question 54

what is the difference in terms of aromas produced by earlier and recent yeasts?

Answer 54

the early yeast e.g. number 6 and 7 produce more muted aromas

Question 55

why the early yeast produce more muted aromas?

Answer 55

they predated the "ginjo boom"

Question 56

One of the reasons why Number 7 became the industry standard but not Number 6

Answer 56

- Number 7 is slightly more attractive, sweeter and fruitier than Number 6. - Number 7 is widely used in making honjozo and futsu-shu - but can also be used in making ginjo style without overt ginjo aromas

Question 57

where did yeast Number 11 come from?

Answer 57

a variant bred from Number 7

Question 58

What's special about yeast Number 11?

Answer 58

- mostly the same as Number 7 - it's especially good at fermenting through to dryness in high-alcohol condition, ideal for making dry non-aromatic sakes.

Question 59

what are the 2 successful new yeasts during the early ginjo style?

Answer 59

- Number 9 - Number 10

Question 60

where and when yeast number 9 is released?

Answer 60

1968 in Kumamoto

Question 61

where and when yeast number 10 is released?

Answer 61

1977, Meiri brewery

Question 62

when is the ginjo boom?

Answer 62

1980s

Question 63

how's the acidity level of yeast number 9 and 10?

Answer 63

- both produce a higher level of acidity - but not as high as no. 6 and 7.

Question 64

what are the characteristics of yeast number 9 and 10 in terms of style?

Answer 64

- higher acidity - prominent, pure ginjo aromas

Question 65

what is the major drive for new yeast types i.e. number 9 and 10?

Answer 65

pursuit of better aromas

Question 66

what is the target of yeast development after the ginjo boom in the 1980s?

Answer 66

- produce extreme versions of ginjo style for competitions - yeast with pronounced ginjo aromas and low acidity

Question 67

Name 2 low acid ginjo yeasts (modern yeasts):

Answer 67

- number 14 - number 1801

Question 68

what is the basic reason to develop different types of yeast throughout the history?

Answer 68

brewers' priority

Question 69

where and when yeast number 14 is released?

Answer 69

1995, Kanazawa

Question 70

when was yeast number 1801 released?

Answer 70

2006

Question 71

what are the parents of yeast number 1801?

Answer 71

crossing of number 9 and 1601

Question 72

examples of "class yeasts"

Answer 72

number 6, 7, 9 and 10

Question 73

examples of "modern yeasts"

Answer 73

number 14, 1801

Question 74

what style of sake the modern yeasts are good at?

Answer 74

ginjo styles

Question 75

what is the criticism of the sake style made with modern yeast?

Answer 75

it has pronounced aromas, but bitter on the palate

Question 76

when was yeast number 1901 released?

Answer 76

2014

Question 77

why the foam during fermentation is a problem?

Answer 77

- tank need extra space for the foam - difficult to clean the tank, risk of contamination

Question 78

why can't just use wine or beer yeast to minimize the foam?

Answer 78

- wine and beer yeast cannot adapt to the high-alocohol, low temperature condition

Question 79

how to find the low-foaming yeast strain?

Answer 79

isolate the mutant yeast in the tank by removing the foam with original yeast attached

Question 80

when did the low-foaming version 901 of yeast number 9 release?

Answer 80

1975

Question 81

which yeast strains do not have their foaming version?

Answer 81

from 1501 to 1901

Question 82

what are the 4 types of yeast?

Answer 82

- reliable fermenters - early ginjo yeast - low acid ginjo yeast - low-foaming yeasts

Question 83

what are the alternatives to BS's yeasts?

Answer 83

- ambient yeast - proprietary yeast - prefectural and regional yeast - blending yeasts

Question 84

where can brewers find ambient yeast?

Answer 84

- on the surfaces of walls, floors, ceilings, fermentation tanks.. in the breweries

Question 85

why wine using ambient yeast for fermentation is less risky than sake?

Answer 85

the grape juice's high acidity protects the yeast from microbial contanimation

Question 86

is using ambient yeast popular in sake?

Answer 86

only a few sakes made this way

Question 87

Other than the usual sources, where brewer isolate yeasts from?

Answer 87

the nature e.g. flowers and trees

Question 88

what's the point to use unique yeast for some breweries?

Answer 88

as a point of difference

Question 89

which prefectures earned reputations of their prefectural yeast?

Answer 89

- Shizuoka - Akita (1990s) - Nagano (1990s)

Question 90

why brewers blend yeasts?

Answer 90

- combine features that already exist - no need to develop new yeast

Question 91

how can a brewer use multiple yeasts in one sake?

Answer 91

- mix yeast strains in the fermentation starter - multiple fermentation starter, each use a different single yeast, blending in the main fermentation - multiple batches of sake, blend after fermentations