Sake Filtration & Fining Flashcards
Understanding Sake: Explaining Style & Quality Chapters 13 & 14
What are the objectives of the brewer at when considering the addition of jōzō alcohol and the filtration process?
- stop the fermentation at the required level of alcohol and sugar
- ensure desirable components get into the sake
- ensure undesirable components stay behind
- extract as much sake as is appropriate for the style being produced
What are the additions that can be made to a sake after filtration?
Only water.
All other additions must be made before filtration.
What is jōzō alcohol made from?
It can be made from rice and locally made, but is often made from molasses and grains, and imported from Brazil.
At what abv is the jōzō added to the sake?
30-40% abv
It’s purchased at 95% and watered back
How much jōzō can be added to premium sake?
No more than 10% of the volume
How much jōzō can be added to futsū-shu?
No more than 50% of the volume (including any other additions)
Why would a brewer decide to add jōzō to his premium sake?
- better extraction of aromas and flavours which are more soluble in alcohol than water and don’t remain in the rice solids
- lighter palate profile - lower sugar, umami, acidity, body
- shorter more cleansing, crisp kire finish
What is the ‘fourth addition’?
A method to adjust the sweetness of a sake.
Kōji is added to steamed rice and water. The enzymes convert starch to sugar without fermentation occurring and the liquid is added to the sake to create the desired balance.
What are the three main methods of filtration?
- Yabuta-shibori or Assakuki (mechanised modern system)
- Funa-shibori (traditional press, sake in cloth bags)
- Fukuro-shibori (drip separation)
Is filtration used for all sake?
Yes - a legal requirement
Is filtration used for nigori sake?
Yes - a legal requirement
What are the benefits of yabuta-shibori?
- efficient extraction of large amounts of liquid
- short filtration time - just a few hours
- pressure can be adjusted for different types of sake so suited to both futsū-shu and daiginjō.
- minimise oxidisation
How long does funa-shibori take?
2 days
What are the benefits and disadvantages of funa-shibori?
- slow and gentle pressing gives fine texture
- small scale allows for precise separation of fractions
- takes 2 days
- risk of oxidisation
What are the benefits and disadvantages of fukuro-shibori?
- even gentler and finer than funa-shibori
- suited to the ultra-premium and competition sake
- slowest method and can only be done on a small scale
- highly labour intensive and time consuming
- very inefficient - the remaining kasu is usually refiltered in a yabuta.
What are the three filtration fractions?
- arabashiri
- naka-gumi
- seme
What is arabashiri?
The free-run liquid from the sake filter.
Lively, with dissolved CO2 and can be cloudy and rough-textured
What is naka-gumi?
The best fraction of the filtration.
Silky texture and pure aromas
What is seme?
The final fraction of the filtration.
Coarsely textured with less aromatic freshness. Possible astringency and bitterness.
Usually blended away in less expensive sake
What are the factors that influence the kasu-buai?
- fermentation technique (higher temperature is more efficient with more dissolved rice so lower kasu-buai, lower temperatures are less efficient)
- filtration techniques (yabuta-shibori more efficient than funa- or fukuro-shibori)
What is the typical kasu-buai of a daiginjō?
40-60%
What is the typical kasu-buai of a futsū-shu?
below 30%
What types of fining can be done to a sake?
- sedimentation (natural settling)
- protein fining (to prevent protein haze)
- charcoal fining (to remove colour and undesirable aromas)
- final filtration (to remove yeast and bacteria)
What are the advantages and disadvantages of charcoal fining?
- remove colour
- remove undesirable aromas
- slows the ageing of the sake
- can make the sake thin and characterless
- in extreme cases the carbon can be tasted
What is hi-ire?
Pasteurisation
Why isn’t sulphur dioxide used as a sake preservative?
- SO2 depends on acidity to be affective (sake much lower in acidity than wine)
- sake cannot legally have preservatives added
What is the most problematic spoilage bacteria?
Hi-ochi kin
What is hi-ochi kin?
Lactic acid spoilage bacteria.
Produces off-aromas, cloudiness and oxidisation
Can be prevented by ultra-fine filtration but usually pasteurisation
At what temperature is the sake heated to during pasteurisation?
60-65°C
When can the sake be pasteurised?
- in bulk, after filtration but before bulk storage
- in bottle (a gentle technique used for ginjō)
- both!
What is nama-chozō?
A sake pasteurised once, after storage in bulk.
What is nama-zume?
A sake pasteurised once, before storage in bulk and bottled without a second pasteurisation
What is ‘once-pasteurised’?
A sake pasteurised just once, after bottling.
How long is sake stored for before release? Why?
Six to twelve months
After pasteurisation, the sake can have an unrefined taste.
What type of blending is used for sake?
- different polishing rates
- different rice types
- different yeast types
- different press fractions
- different ages or storage methods
- higher and lower amounts of sake lees for nigori
