C10 - Water and yeast - completed Flashcards
Which two ingredients of sake are not derived from rice?
Water and yeast
Over 80% of the sake is made up of what?
water
Besides alcohol, what else does yeast create during fermentation?
many of the signature aromas
Why historically breweries are located near water source?
- water made up over 80% of the sake
- sake production needs a lots of water for: making the sake, cleaning…etc.
what are the two major source of water for most of the breweries?
- subsoil
- tap water
can brewer alter the content of the water?
yes, can filter and alter the mineral content, acidity of the water.
What is the upper limit in the food product manufacturing standard control?
- level of organic substances
- level of iron
how strict is the standard on the max. level of iron in the water for making sake vs. tap water?
- the limit is less than 1/10 of the level permitted in tab water
What happen to the sake if iron level of the water is too high?
- it gives the sake a reddish-brown colour
- spoils the aroma and taste
Measuring water’s “hardness” and “softness” are determined by which two elements?
- calcium
- magnesium
which element is usually the dominant metal in water?
calcium
which element is the most important in water for making sake?
magnesium
why magnesium in water is more important in making sake?
- it enhance the metabolism of the yeast
what are the other two elements in water aid the growth of yeast and koji?
- potassium
- phosphorus
what kind of water is once preferred by brewers for fast and stable fermentation?
mineral rich i.e. magnesium, potassium, phosphorus
Why mineral rich waters are good for fast and stable fermentation?
the minerals for nutrients for the yeast, which can reduce risks in contamination, weak or starving yeast during fermentation
where was the famous mineral-rich water found?
Hyogo prefecture / Kobe / Nada / miya-mizu water
what style of sake is produced using the miya-mizu water in Kobe?
more restrained, drier style
Where can you find the famous lower mineral water?
Kyoto / Fushimi water
what style of sake is produced using the Fushimi water in Kyoto?
softer style
Other than water, magnesium, potassium and phosphorus can also be found in which sake ingredient?
rice
What is the concern in using the nutrients in rice rather than water to feed the yeast?
- need to be large amount and fast enough to avoid contamination or starving yeast.
which koji style should be used when using low mineral water but aim for a vigorous fermentation e.g. the Kyoto style?
so-haze
what can the brewer do if the water is low in mineral but want to use tsuki-haze koji to produce ginjo style sake
adjust the mineral content of the water
which area makes ginjo style sake using low mineral water and tsuki-haze koji?
Saijo, Hiroshima
what are the 3 major output of yeast from brewer’s point of view?
- alcohol
- aromas
- organic compounds e.g. acids
Other than aromas, what else does yeast determine the sake’s style?
- texture
- acidity
what are the 3 major acids found in sake?
- lactic acid (by shubo)
- malic and succinic acids (by yeast)
yeast activity (speed) are controlled by…?
temperature
at what temperature range, yeast become inactive?
3 - 5C
typically, wine yeasts stop working (dormant) when alcohol level reach ?? %abv?
15 - 16% abv
How beer and wine yeast behave differently from sake yeast in high alcohol environment?
- wine and beer yeast will dormant to protect themselves
- sake yeast keeps working, produce even more alcohol
why yeast doesn’t like high alcohol environment?
alcohol is toxic to yeast, it can be killed by strong alcohol.
What is the maximum alcohol level yeast can produce in making sake?
22% abv
what if the sake has alcohol level over 22% abv?
it cannot be called sake legally
traditionally, where do the yeast come from?
ambient brewery yeast - which attached to the surfaces in the brewery
what is the problem using ambient brewery yeast?
the result is unpredictable, depends on which yeast strain complete the fermentation
what made sake yeast behave not the same as wine and beer yeast?
mutation
initially, how brewers propagate and re-use yeast?
they take the yeast from the foam of a successful fermentation and inoculate in the next fermentation
what are the problems of propagate yeast from the former fermentation?
- 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
what caused the flavour production inconsistent when propagate the yeast?
- microbial contamination
How brewing science improved the consistency of yeast?
- it can isolate individual strains of yeast
- avoid mutation in propagation
why brewers now rely on suppliers in sourcing yeast?
because isolating and maintaining strains of yeast is a specialised skill
where brewers buy their yeast from?
Brewing Society of Japan (BS)
since when, Brewing Society of Japan start distribute selected yeast widely?
1906
What is the main action the Brewing Society of Japan does to yeast?
- Brewing Society of Japan manages the multiplication of yeast
- number and pack the yeast in ampules to avoid contamination
where were the Brewing Society of Japan yeasts found?
- first isolated by a particular brewery
- improvement on earlier numbered yeasts
- developed by other organisations i.e. regional research institute or tax bureau
which year did Brewing Society of Japan Yeast “Number 1” released?
1916
which year did Brewing Society of Japan Yeast “Number 8” released?
1963
Which brewery isolated BS Yeast “Number 6”? In which year?
Aramasa brewery in 1935
Which brewery isolated Brewing Society of Japan Yeast “Number 7”? In which year?
Miyasaka brewery in 1946
what is the top priority of the yeast quality?
a successful, complete fermentation
why a successful, complete fermentation is important to both the brewery and the government?
- the brewer don’t want to lose the whole batch of production
- sake is a big proportion of tax revenue to the government
what is the difference in terms of aromas produced by earlier and recent yeasts?
the early yeast e.g. number 6 and 7 produce more muted aromas
why the early yeast produce more muted aromas?
they predated the “ginjo boom”
One of the reasons why Number 7 became the industry standard but not Number 6
- 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
where did yeast Number 11 come from?
a variant bred from Number 7
What’s special about yeast Number 11?
- 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.
what are the 2 successful new yeasts during the early ginjo style?
- Number 9
- Number 10
where and when yeast number 9 is released?
1968 in Kumamoto
where and when yeast number 10 is released?
1977, Meiri brewery
when is the ginjo boom?
1980s
how’s the acidity level of yeast number 9 and 10?
- both produce a higher level of acidity
- but not as high as no. 6 and 7.
what are the characteristics of yeast number 9 and 10 in terms of style?
- higher acidity
- prominent, pure ginjo aromas
what is the major drive for new yeast types i.e. number 9 and 10?
pursuit of better aromas
what is the target of yeast development after the ginjo boom in the 1980s?
- produce extreme versions of ginjo style for competitions
- yeast with pronounced ginjo aromas and low acidity
Name 2 low acid ginjo yeasts (modern yeasts):
- number 14
- number 1801
what is the basic reason to develop different types of yeast throughout the history?
brewers’ priority
where and when yeast number 14 is released?
1995, Kanazawa
when was yeast number 1801 released?
2006
what are the parents of yeast number 1801?
crossing of number 9 and 1601
examples of “class yeasts”
number 6, 7, 9 and 10
examples of “modern yeasts”
number 14, 1801
what style of sake the modern yeasts are good at?
ginjo styles
what is the criticism of the sake style made with modern yeast?
it has pronounced aromas, but bitter on the palate
when was yeast number 1901 released?
2014
why the foam during fermentation is a problem?
- tank need extra space for the foam
- difficult to clean the tank, risk of contamination
why can’t just use wine or beer yeast to minimize the foam?
- wine and beer yeast cannot adapt to the high-alocohol, low temperature condition
how to find the low-foaming yeast strain?
isolate the mutant yeast in the tank by removing the foam with original yeast attached
when did the low-foaming version 901 of yeast number 9 release?
1975
which yeast strains do not have their foaming version?
from 1501 to 1901
what are the 4 types of yeast?
- reliable fermenters
- early ginjo yeast
- low acid ginjo yeast
- low-foaming yeasts
what are the alternatives to BS’s yeasts?
- ambient yeast
- proprietary yeast
- prefectural and regional yeast
- blending yeasts
where can brewers find ambient yeast?
- on the surfaces of walls, floors, ceilings, fermentation tanks.. in the breweries
why wine using ambient yeast for fermentation is less risky than sake?
the grape juice’s high acidity protects the yeast from microbial contanimation
is using ambient yeast popular in sake?
only a few sakes made this way
Other than the usual sources, where brewer isolate yeasts from?
the nature e.g. flowers and trees
what’s the point to use unique yeast for some breweries?
as a point of difference
which prefectures earned reputations of their prefectural yeast?
- Shizuoka
- Akita (1990s)
- Nagano (1990s)
why brewers blend yeasts?
- combine features that already exist
- no need to develop new yeast
how can a brewer use multiple yeasts in one sake?
- 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
