Water and Yeast Flashcards
Understanding Sake: Explaining Style & Quality Chapter 10
Where do brewers source their water?
It varies from brewery to brewery.
- natural subsoil sources
- filtered tap water for consistancy
Whatever the source, brewers can filter and alter the mineral and acid content of their water
What are the standards that water for sake production must meet?
- food manufacture standards
- upper limits on organic substances
- the level of iron permitted is less than 10% of what is allowed for tap water
Why is a low iron content a requirement of sake water?
Too much iron and the sake will be a reddish-brown colour and spoil aroma and flavour.
What does ‘hardness’ and ‘softness’ of water refer to?
The dissolved magnesium and calcium in the water
- calcium is the dominant metal
- magnesium enhances the metabolism of the yeast
Potassium and phosphorous also aid healthy yeast and kōji growth but are not discussed when water hardness is measured.
What role does magnesium play in sake production?
Higher levels of magnesium in the water enhances the metabolism of the yeast
Is Japan’s water generally hard or soft, from an international perspective?
Soft
What style of sake do mineral-rich waters high in potassium, phosphorous and magnesium produce?
Fast, stable fermentation that produces a restrained and dry style.
Most famous from the Nada area of Kōbe
What is the water from the Nada area of Kōbe in Hyōgo prefecture called?
Miya-mizu
‘Miracle water’
Where is miya-mizu water found?
Nada area of Kōbe in Hyōgo prefecture
‘Miracle water’ high in minerals
Which area of Kyōto famous for sake has low mineral content in the water and produces soft-style sake?
Fushimi
Why are sake from Fushimi in Kyōto produced in a softer style?
Low mineral content in the water
What is the benefit of using sō-haze kōji in a sake made from low mineral water?
The large quantity of enzymes results in the rice breaking up quickly which provides nutrient for the yeast and a healthy ferment.
If tsuki-haze was used with soft water, it would take time for the yeast colony to multiply and there is a risk of contamination or running out of nutrient. For the production of ginjō sake in a soft water area, the brewer would adjust the mineral content of the water.
How can a brewer produce a ginjō sake using tsuki-haze in a soft water site?
By adjusting the mineral content of the water, he can provide more nutrient fo r the kōji and yeast.
What are the three roles of yeast in sake production?
- convert sugar to alcohol
- create aroma compounds
- create organic compounds including acids
Which has more impact on the style of sake produced - rice, yeast or kōji?
Yeast.
Rice and kōji only have a subtle effect.
Yeast impacts aroma, texture and acidity
What impact does yeast have on the style of a sake?
Aroma
Texture
Acidity
Which yeast species is used for making sake?
Saccharomyces cerevisiae
Why does Saccharomyces cerevisiae continue to work in a sake fermentation when it is killed at similar alcohol levels in beer or wine production?
Mutated yeasts that can operate at high alcohol levels have been selected by brewers.
What is the upper permitted legal abv % for sake?
22%
Above 22%, it ceases to be legally sake
Who is the main supplier of yeasts to the sake industry?
Brewing Society of Japan
When did the Brewing Society of Japan begin to distribute sake yeast?
1906
Name two yeasts that are known for reliable fermentations.
#6 #7
Name two yeasts that are referred to as ‘early ginjō’ yeast and were developed in the pursuit of better aromas.
#9 #10
Sake yeasts #1 - #8 were released between 1916 and 1963. What was their intent?
- brewers wanted reliable fermentations, so no batches were lost
- sake was a valuable tax revenue stream for the Japanese government so reliability was important from this perspective
Which yeast was isolated at Aramasa brewery in Akita and released in 1935?
6
In which year was #6 yeast released, after being isolated at which brewery?
1935
Aramasa in Akita prefecture
Which yeast was isolated at Miyasaka brewery in Suwa city and released in 1946?
7
In which year was #7 yeast released, after being isolated at which brewery?
1946
Miyasaka brewery in Suwa city
Which yeast is the ‘industry standard’, used for much futsū-shu?
7
What is the character of yeast #6?
- reliable fermentation
- produce more acidity than more recently isolated yeasts
- muted aromas (pre-dates the ginjō boom)
- less fruity than #7
What is the character of yeast #7?
- reliable fermentation
- produce more acidity than more recently isolated yeasts
- muted aromas (pre-dates the ginjō boom)
- sweeter and more fruity than #6
- the industry standard, used for futsū-shu as well as hon-jōzō, junmai and occasionally ginjō
How are yeasts #7 and #11 comparable?
Yeast #11 was bred from #7 and they have similar characteristics.
Yeast #11 is especially good at fermenting through to dryness in high alcohol conditions, so useful for dry and non-aromatic sake.
