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カテゴリ: ワインエキスパート受験

アル添について
Jozo alcohol are added to any sake for following reason
・stop the fermentation
・to ensure desireble conponents to be extracted, and to get into sake →Increase aromas
・undesireble conponents to stay behind→lighter palate profile

For premium sake, 10% of addition is allowed except for Junmai.
For Futsu-shu 50% is allowed. Also sweetness, acidity and umami are allowed to add.

This process is not categorised as 'fortified' since water is added after the filteration.
 
四段
To control(increase) the level of sweetness Forth addition (mixture of water, rice, koji=dissolved sugar) is added to Aruten sake.

上槽
Filteration is to separate and remove the solid part.
・Yabuta shibori(assakuki) 
 This can extract large volume of liquid very rapidly.
 By decreasing the air pressure also possible to produce high quality sake. 
  Good at minimising oxidation.
・Funa shibori
  Traditional way.
 Limited use for some premium sake.
 Danger of oxidation.
・Funkuro shibori.
 No pressure added, relying only to gravity.
 Sake is collected to Tobin, 18L bottle.
 The usage is limited to super premium sake for competition.
 Danger of oxidation.
・Centrifuge separator
 Minimal oxidation risk.
 Only used for limited number of breweries.

あらばしり…Free run liquid, contains some carbon dioxide, extreme freshness
中どり…Highest quality sake, with silkiest texture and purest aromas. called To-bin gakoi for shizuku shibori
責め…Rough texture and less aromatic freshness

酒粕
Kasu buai defers depending on the way of filteration and how it is made.
Daiginjo has 40-60% of kasu buai, Futsu-shu will be around 30%.



 

Moromi
・Three stage addition(三段仕込み)
・The temperature control(12-18c, 10-12 for ginjo)
・End fermentation

 三段仕込み
If the entire amout is added to the tank at once, there is a delay before yeast reach a population large enough to balance the monversion of starch to sugar by the koji enzymes.
This delay has risk of contamination, adding more lactic acid will be a solution but it'll be too acidic.
Day1: Add 1/6 of moromi
Day2: none (wait for the yeast to multiply)
Day3: Add 2/6 of moromi (In this time 3/6, it means half of the tank is full)
Day4: Add the rest(3/6) and the tank will be full. cool the temperature to 6-10c.

Temperature control
Enzyme and yeast increase when in higher temperature.
If the target temperature is around 17c, more koji is required for the yeast.
If the temperature is around 10c, the amount of koji exceeds the yeast consumption.
When in high temperature, it produces more alcohol, and yeasts will be dead by the alcohol. The dead yeast produce undesireble flavour.

High Umami
The rice should be high polishing ratio with so-haze koji. 
Kasu ratio will be lower in higher temperature, becase most of the nutrients such as amino acid and peptide are extracted to sake.

Ginjo fermentation
The fermentation is processed under stress for the yeasts, lower temperature and less enzyme.
Isoamyl acetate and ethil caproate are extracted under this condition. 
The kasu racio will be higher since most of the nutrent such as amino acid and organic acid remain in the rice.

Batch size
For ginjo style 1 kg of rice produce 2.5L of sake, for futsu-shu it will be 5L out of 1 kg of rice.



 

Create the starter not only to increase the yeast, but also to increase lactic acid for safe fermentation.
The percentage of koji in shubo is around 30-33%, and the total percentage of the koji is 20-23%.
If the whole amount of rice is 1000kg, approx. 200kg is the total amout of koji. In shubo, 60kg is koji.

For temperature control of shubo, an equipment called daki, stainless steel made bucket-like tool used with hot water or ice, is used.
Alternatively pipes, jackets of hot or cold water are also used.

For acidity, brewers try to increase the amount of lactic acid.
One method is directry adding lactic acid(sokujo), another is to mix the rice very well to grow the population of lactic acid.

Sokujo-moto
The temperature is 20-25c, takes 14 days to grow.
Less umami and acidity in the taste.

Kimoto and Yamahai
The temperature is around 6-7c, takes about 28 days.
First bacteria converts nitrates to nitrites, then lactic acid are created.
High concerntration of sugar, low PH, low temperture avoid the growth of undesireble yeast.
Yamahai was born in 1909, by skipping the stage of turning rice into paste.
More umami and acidity, can be more interesting flavour. 

Other kinds of  shubo
・ko-on toka moto
・Improve techniques (Higer temperature sokujo-moto, kimoto mixing machine)
・bodai-moto
・No shubo used (when black or white koji is used citric acid is enough to kill the undesireble yeasts)

 

Water
Water softness or hardness is basically important for sake.
Iron is the most undesireble content of the water, it spoils color, aroma and flavour, and soft water usually contains less iron (calsium and magnesium occurs together with other metals).
Magnesium enhances the metabolism of the yeast.
Potassium and phosphorus helps the healthy growth of yeast and koji.

Water matters for stable fermentation, miya-mizu is one famous example of rich in mineral water.
Because of healthy and fast fermentation floral ginjo aromas are hardly appears to the sake of Nada area.

Rice takes time to break up the fermentation, this waiting time can leads to contamination.
To avoid this, using so-haze koji is one option to break up the rice rapidly.
Alternatively Controlling the mineral content of the water, especially for ginjo style with tsuki-haze koji, in Saijo(Hiroshima) area.

Yeast
The yeast for sake starts to activate from low temperature around 6c, and alcohol level reaches around 20-22 in maximum.
Traditionally brewers were using the natural yeast they had in their brewery, but it had the risk of contamination.
Brewing society has started to isolate and distribute the stable yeast, each of them keeps the characteristics of the style. 
Stable fermentation is important not to lose the alcoholic tax revenue for the government.
・No. 6-7: Produce more acidity and muted aroma, mainly used for futsu-shu, honjozo, and junmai.
・No. 9-10: Produce high level of acidity but not more than 6-7, ginjo aroma. 
・No. 14-1801: 'modern yeasts', produce low acidity and ginjo aroma.
・No. n01: Low form yeasts. Avoid the risk of overfloat, easier to clean and avoid contamination.  

Ambient yeast: to make the product more original.
Proprietary yeast: isolate the yeast from flowers or trees, for more unique expression.
Prefectual and regional yeasts: ex. very soft isoamyl acetate banana aroma of Shizuoka, very successful ginjo yeast of Akita and Nagano.

Blending yeasts
mix
・ yeast strain
・starter
・liquid after fermentation 

Usually 20% of the total amout of rice is Koji.
Rice should be warm temperature otherwise the mould will stop growing. 
The mould grows by sending feeding tubes into rice, this tube provides enzymes to break the starches into glucose.
Koji mould also provides 
・amino acids, peptide
・vitamins (for yeast)
・lipids and proteins

Koji mould has 3 types, yellow, black and white.
Yellow is usually used for sake because this produces very low levels of citric acid.

For growing koji there are 2 types, spores(種麹) and granulated(米麹).
The mainstream is using spores, however granulated koji is still used for some ginjo sake(tsuki-haze).

So-haze
If the moisture content of the rice is too high it will be uneven mould growth called nuri-haze.
This koji is ideal for
・Futsu-shu
・Premium sake with full body flavour.

Tsuki-haze
The feeding tube of the mould grows into the centre of the grain, it is almost impossible to use machine for this style.
Below is the necessary conditions to grow tsuki-haze
・low level of moisture content for slow controlled fermentation to develop ginjo aromas
・less amount of koji spores
・warmer but less humid koji room
Lipid of the koji also produces ginjo aroma.

Making Koji
Bringing in (Hikikomi)
・32-35c
(H)Steamed rice is cooled and laid out onto toko
(M)Cooling conveyor

Spreading the spores(Tanekiri) 
・1-3h after bringing in
・30-35c
(H)sprinkle the spore by hand and wrap it with blanket
(M)spray the spore using steam

Re-breaking up(kirikaeshi)
・10-12h
・33-31c
(H)mix the rice again and break the clumps
(M)the rice is broken up by the rotating rollers

Mounding(Mori) 
・20-23h
・33-35c
(H)Keep the rice to bed(toko, for futsu-shu, honjozo, junmai), box(hako, not for futsu-shu) or tray(futa, suitable for ginjo) for desired style. 
(M) just leave the rice in the drums.

Middle work(Naka shigoto)
・30-33h
・36-33c, rising again to 38c
(H)make the koji shalowly to provide oxgen and evaporate the water
(M)the rotate roller keeps on rotating to redistribute water and heat 

Final work(shimai shigoto)
・36-38h
・higher thatn 38c avoid exceeding 43c
(H)Increasing the surface area to reduce heat and dry the rice
(M) the rotate roller keeps on rotating to redistribute water and heat 

Sending out(de-koji)
・44-48h
・reduced from 38c
(H)Transfer the vessels to cool down the koji to stop the growth
(M)Lower the temperature inside the drum 

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