C11 - The Fermentation Starter (Shubo/Moto) - completed Flashcards
what is the common aim of the producers using fermentation starter in different alcoholic beverage?
to produce a healthy population of their selected yeast
what is the function of the shubo/moto?
- create an acidic environment using lactic acid
- develop a sufficient, concentrated population of fermentation yeast
- in order to carry out the main fermentation successfully
percentage of the small shubo tank compare with the size of the main fermentation tank
6 - 10%
what’s special about the koji used in making shubo vs. in the main fermentation?
- relatively high in proportion
- typically 30 - 33% of the rice used is koji
typically what’s the percentage of koji rice is used across the whole fermentation?
20 - 23%
how long it takes to make a shubo?
14 - 28 days (depends on method)
what techniques the brewers use to manage the shubo making process?
- by managing the temperature and the acidity of the shubo
which tool is used for adjusting the temperature during shubo production?
daki - a bucket-like container, made from aluminium or stainless steel
why temperature control is important when making shubo?
- need to ensure the yeast multiply at the same pace as the koji mould enzymes convert starch to sugar
other than daki, what other devices can be used to adjust the temperature?
pipes or jackets of hot or cold water
what are the ingredient of shubo?
rice, water, koji, (lactic acid)
why microbial contamination is a major risk in making sake?
- 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
in order to protect the yeast to populate in shubo, what is needed?
- high level of lactic acid
what are the 3 methods of making shubo?
- sokujo-moto
- kimoto
- yamahai
which method is the most common in making shubo?
- sokujo-moto
what is the disadvantage of the kimoto/yamahai method?
- it’s vulnerable to spoilage
- take longer time
are sokujo-moto, kimoto, yamahai legally defined terms?
No
which method is a reliable way to create shubo during 1600s to mid 1800s?
kimoto
when did the brewers start to discover how the kimoto method works scientifically?
late 1800s
what was the findings in late 1800s when discovering why kimoto works?
- it’s the lactic acid which protect the yeast
- this ultimately led to the development of sokujo-moto.
when did sokujo-moto development become perfect?
the early 1900s
what is the major difference in making sokujo-moto with kimoto/yamahai?
- it adds lactic acid directly to the shubo
what else sokujo-moto changed the way of making shubo for centuries?
- it raised the temperature to 20 - 25C
- ideal for both koji enzyme extraction and the yeast multiplication
what was the temperature range in making shubo in the old days?
6 - 7C
what are the difference in terms of results of sokujo-moto vs kimoto/yamahai?
- 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
what is the advancement of sokujo-moto recently?
- the “fast sokujo” or ‘medium temperature sokujo’
- start from a even higher temperature
- complete in 10 days
where and when did the prototype of kimoto develop?
- Nada
- late 1600s
how kimoto is made?
- starting with a small batch
- keeps pounding the rice and koji into a smooth paste with poles or paddles
why pounding in kimoto is neccessary?
- 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
what temperature range kimoto starts from?
6 - 7C
in the initial stage of making kimoto, which process starts first, before any microorganism begin to grow?
the starch to sugar conversion
what is the only bacteria take place in the initial stage of making kimoto?
- those convert nitrates to nitrites
which one is the cold-tolerant bacteria in the initial stage of making kimoto?
lactic acid bateria
describe the environment of kimoto which inhibit unwanted microbes to grow
- high concentration of sugar
- low pH (high acidity) due to lactic acid
- low temperature (6-7C)
- presence of nitrites
why kimoto method is more prone to spoilage?
because before the acidity level is high enough, unwanted bacteria still have chance to spoil the shubo.
today, what is the timing of adding yeast to kimoto?
14 days from the start of making kimoto
how long the added yeast takes to multiply until the kimoto is ready?
another 14 days. (total 28 days)
what is the major difference between kimoto and yamahai in terms of process?
- 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
which year was yamahai discovered by scientist?
1909
why some brewers still use kimoto/yamahai despite the extra time and risk?
- the active microbes can produce interesting flavours
- rich flavours
- higher acidity
- complex nutty and caramel flavours from deliberate oxidation
what are the other options of creating shubo?
- ko-on toka moto
- bodai moto
- use mechanical mixers in the mixing stages of kimoto
- no shubo - use black or white koji mould
what’s special about ko-on toka moto?
- 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 permium sake
what’s special about bodai moto?
- 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
what’s special about black and white koji mould?
- 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
