C11 - The Fermentation Starter (Shubo/Moto) - completed Flashcards

1
Q

what is the common aim of the producers using fermentation starter in different alcoholic beverage?

A

to produce a healthy population of their selected yeast

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2
Q

what is the function of the shubo/moto?

A
  • create an acidic environment using lactic acid
  • develop a sufficient, concentrated population of fermentation yeast
  • in order to carry out the main fermentation successfully
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3
Q

percentage of the small shubo tank compare with the size of the main fermentation tank

A

6 - 10%

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4
Q

what’s special about the koji used in making shubo vs. in the main fermentation?

A
  • relatively high in proportion
  • typically 30 - 33% of the rice used is koji
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5
Q

typically what’s the percentage of koji rice is used across the whole fermentation?

A

20 - 23%

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6
Q

how long it takes to make a shubo?

A

14 - 28 days (depends on method)

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7
Q

what techniques the brewers use to manage the shubo making process?

A
  • by managing the temperature and the acidity of the shubo
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8
Q

which tool is used for adjusting the temperature during shubo production?

A

daki - a bucket-like container, made from aluminium or stainless steel

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9
Q

why temperature control is important when making shubo?

A
  • need to ensure the yeast multiply at the same pace as the koji mould enzymes convert starch to sugar
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10
Q

other than daki, what other devices can be used to adjust the temperature?

A

pipes or jackets of hot or cold water

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11
Q

what are the ingredient of shubo?

A

rice, water, koji, (lactic acid)

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12
Q

why microbial contamination is a major risk in making sake?

A
  • when steamed rice, water and koji mixed together, it’s low acidic, cannot protect the yeast
  • shubo is a very attractive environment to microorganisms
  • koji mould enzymes is slow in converting starch to sugar, means less food to support rapid yeast population
  • bacteria multiply much more faster than yeast
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13
Q

in order to protect the yeast to populate in shubo, what is needed?

A
  • high level of lactic acid
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14
Q

what are the 3 methods of making shubo?

A
  • sokujo-moto
  • kimoto
  • yamahai
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15
Q

which method is the most common in making shubo?

A
  • sokujo-moto
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16
Q

what is the disadvantage of the kimoto/yamahai method?

A
  • it’s vulnerable to spoilage
  • take longer time
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17
Q

are sokujo-moto, kimoto, yamahai legally defined terms?

A

No

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18
Q

which method is a reliable way to create shubo during 1600s to mid 1800s?

A

kimoto

19
Q

when did the brewers start to discover how the kimoto method works scientifically?

A

late 1800s

20
Q

what was the findings in late 1800s when discovering why kimoto works?

A
  • it’s the lactic acid which protect the yeast
  • this ultimately led to the development of sokujo-moto.
21
Q

when did sokujo-moto development become perfect?

A

the early 1900s

22
Q

what is the major difference in making sokujo-moto with kimoto/yamahai?

A
  • it adds lactic acid directly to the shubo
23
Q

What are the differences in making sokujo-moto versus traditional shubo?

A
  • Add lactic acid directly
  • it raised the temperature to 20 - 25C
  • ideal for both koji enzyme extraction and the yeast multiplication
24
Q

what was the temperature range in making shubo in the old days?

A

6 - 7C

25
Q

what are the difference in terms of results of sokujo-moto vs kimoto/yamahai?

A
  • it’s faster, take 14 days instead of 28 days.
  • it has more precise control in the level of lactic acid, usually lower than kimoto/yamahai
  • the shorter time and no need to rely on lactic acid bacteria avoids variations that may led to failure
  • less umami in flavour
26
Q

what is the advancement of sokujo-moto recently?

A
  • the “fast sokujo” or ‘medium temperature sokujo’
  • start from a even higher temperature
  • complete in 10 days
27
Q

where and when did the prototype of kimoto develop?

A
  • Nada
  • late 1600s
28
Q

how kimoto is made?

A
  • starting with a small batch
  • keeps pounding the rice and koji into a smooth paste with poles or paddles
29
Q

why pounding in kimoto is neccessary?

A
  • this increase the contact of the rice starch and koji enzymes
  • speed up the conversion process
  • thus speed up the yeast population
  • thus yeast becomes the dominant bacteria faster
30
Q

what temperature range kimoto starts from?

A

6 - 7C

31
Q

in the initial stage of making kimoto, which process starts first, before any microorganism begin to grow?

A

the starch to sugar conversion

32
Q

what is the only bacteria take place in the initial stage of making kimoto?

A
  • those convert nitrates to nitrites
33
Q

which one is the cold-tolerant bacteria in the initial stage of making kimoto?

A

lactic acid bateria

34
Q

describe the environment of kimoto which inhibit unwanted microbes to grow

A
  • high concentration of sugar
  • low pH (high acidity) due to lactic acid
  • low temperature (6-7C)
  • presence of nitrites
35
Q

why kimoto method is more prone to spoilage?

A

because before the acidity level is high enough, unwanted bacteria still have chance to spoil the shubo.

36
Q

today, what is the timing of adding yeast to kimoto?

A

14 days from the start of making kimoto

37
Q

how long the added yeast takes to multiply until the kimoto is ready?

A

another 14 days. (total 28 days)

38
Q

what is the major difference between kimoto and yamahai in terms of process?

A
  • yamahai mix koji and water together, and then steamed rice, to start the starch to sugar conversion,
  • no need of the laborious pounding process as in kimoto
39
Q

which year was yamahai discovered by scientist?

A

1909

40
Q

why some brewers still use kimoto/yamahai despite the extra time and risk?

A
  • the active microbes can produce interesting flavours
  • rich flavours
  • higher acidity
  • complex nutty and caramel flavours from deliberate oxidation
41
Q

what are the other options of creating shubo?

A
  • ko-on toka moto
  • bodai moto
  • use mechanical mixers in the mixing stages of kimoto
  • no shubo - use black or white koji mould
42
Q

what’s special about ko-on toka moto?

A
  • it use very high temperature in the initial stage to sterilise the mixture and accelerate the starch to sugar conversion
  • it’s suitable for very pure, clean style of premium sake
43
Q

what’s special about bodai moto?

A
  • it use sour water to play the role of lactic acid in sokujo-moto
  • the sour water comes from mixing bacteria decay rice into water
44
Q

what’s special about black and white koji mould?

A
  • they create higher and different acid (citric acid)
  • the acidity level is enough to start a fermentation with small yeast population
  • these koji moulds were normally used for making shochu