Yeast playes a critical role in determining what two things?
Quality and style
When did the Brewing Society of Japan begin distributing yeast?
1906
How is yeast selected?
Yeasts were selected and isolated from the main fermentation mash of breweries that had produced good sake.
By law, all sake breweries must purchase their yeast from the Brewing Society of Japan. T or F
False Many breweries have proprietary strains.
Kyōkai kōbo
Yeast from the Brewing Society of Japan, also called Brewing Society Yeast.
Strong fermentation, clear fragrance and mellow flavour. Suitable for Kimoto or creating light taste
- isolated at Aramasa in Akita; 1935
- still used by Aramasa regularly today
- robust fermentation and muted aromatics
- generally high acid, but resulting sake is often mellow
- one of the reliable fermenters
6
6号酵母
Current industry standard. Slightly sweet fragrance and vivacious flavour. Suitable from Ginjo to Futsushu.
- one of the reliable fermenters
- used for ginjo if ginjo-ka not desired
- isolated at Masumi, Nagano, 1946
- most widely used yeast for brewing sake
- mellow, slightly fruity, vigorous fermentation
- often produces banana and bubble gum notes
- can produce high acidity, but easy to control in the brewery
7
7号酵母
- variant of #7, can withstand very high alcohol, so used to make super dry sake
- produces high acidity
- hints of apple
- one of the reliable fermenters
11
11号酵母
Floral and sweet fragrance and vivacious flavour. Most common for competition sake until 1990s. Shorter length for main mash fermentation. Suitable for Ginjo.
- aka: Kumamoto Kobo 熊本酵母
- isolated at Koro; Kumamoto, 1953
- Koro is a research brewery
- recently started making sake for the market
- can still be purchased from Koro
- high fragrance both floral and fruity, but crisp
- intense fermentation
- Classic and popular all-around Ginjo yeast
- early ginjo yeast
9
9号酵母
Low-acidity, light flavours. Characteristic aroma of Ginjo. Longer fermentation period in lower temperature. Weak alcohol resistance. Suitable for Junmai or Ginjo.
- aka: Ogawa Kobo 小川酵母
- commonly used in Tohoku (the north of Honshu)
- isolated 1950’s by Ibaraki brewery Meiri Shurui
- ferments well at very low temperatures, low acid, aromatic
- doesn’t play well with Omachi rice
- early ginjo yeast
10
10号酵母
Low acidity, pear and apple. Middle length fermentation in lower temperature. Suitable for Ginjo and other premium category sake
- aka: Kanazawa Kobo 金沢酵母
- isolated in Kanazawa;1992
- low acidity, malic (apple, pear)
- must be fermented slow and cold
- low acid ginjo yeast
14
14号酵母
- newer
- very fruity, lower acid, and mellow
- low foaming
1801
1801号酵母
Foamless Yeast
- add -01 suffix
- ex: #901 is a foamless #9
- no foam rises in the tank, making it easier to work with and clean up
- dried foam is concentrated with microbes– posing a serious risk of spoilage
- foamless yeast is extremely popular
What is an advantage of foamless yeast?
Dried foam is concentrated with microbes– posing a serious risk of spoilage
What are the reliable fermenters?
6, #7, #11
Brewers have been utilizing microbial technology to produce yeasts designed to increase the amount of _______________ delivering a ______________ aroma.
Brewers have been utilizing microbial technology to produce yeasts designed to increase the amount of esters delivering a fruity aroma.
1501
Isolated in Akita, 1990.
Low acidity and notably fruity aroma of ginjo.
The first yeast developed solely as a non-foaming yeast.
Why are special yeast strains needed?
They must be able to keep working in a higher alcohol environment (20%abv or higher), they must be abe to work at low temperatures, and they may need to work with low levels of sugar.
Yeast need what?
From rice: Sugar and other nutrients
From rice + koji: vitamins and nitrogen
From rice + water: magnesium, phosphorous, potassium
Most sakes are made using ambient yeast.
T or F
False
Why is #9 (#901) and #1801 a popular blend of yeast?
1801 has high aromatics that are mitigated by adding #9.
What are three ways to blend yeasts?
- add a mix of yeast strains to the starter.
- create multiple fermentation starters, each with a unique strain, then combine the starters for fermentation.
- create multiple batches of sake, each with a unique yeast, and blend the sakes at some stage after fermentation.
Brewers are still experimenting to determine the best methods for combining yeasts.
T or F
True
What are the low acid ginjo yeasts?
14, #1801
