C13 - Jozo Alcohol and Filtration - completed Flashcards
what is the legal requirement of sake in terms of filtration?
all sake must be filtered
what are the aims of the brewer in filtration?
- stop the fermentation when alcohol and sugar have reached the target levels
- maximise the extraction of desirable components i.e. alcohol, sugar, water, aroma, texture
- leaving all unwanted components behind - rice solids, yeast particles, coarse texture
- maximise the extraction of sake of the desired style
What techniques do brewer’s use in filtration?
- temperature control
- adding jozo alcohol - selectively extract particular aromas, flavours
- using filter
how the fermentation is stopped?
- by lower the temperature to 3 - 5C
what happen to the yeast when the temperature is lowered to 3 - 5C?
- it will halt the yeast but not killing them
why not kill the yeast when fermentation is completed?
because dead yeast will add undesirable flavours to the sake
what happen if the sake is filtered too early?
it will have green and sour smells
after filtration, what is the only ingredient allowed to add to the sake?
water
before filtration, what is allowed to add to ALL sake (premium and futsu-shu)?
water, rice and koji
before filtration, what additives are allowed to add to futsu-shu only?
- sweetness (sugar, glucose)
- acidity (organic acids)
- umami (amino acids)
what are the maximum amount of jozo can be added to:
- junmai
- premium sake
- futsu-shu?
- none
- 10%
- 50% (including any other flavour additives)
*this is the amount of alcohol at 95% abv vs. the amount of polished rice
what is the alcohol level of the jozo when it’s imported?
over 95% abv
to remove all flavours
what is the raw materials making the jozo alcohol from Brazil?
molasses and/or grains
where is the common source country for importing jozo alcohol?
Brazil
jozo alcohol is allowed to add to the sake at which stage?
before filtration
what is the legal requirement of the jozo in terms of ingredient and production method?
it must be distilled from an alcoholic beverage fermented from raw agricultural materials
what is the alcohol level of the jozo when it’s stored by the brewer?
30 - 40% abv
to avoid risk of fire
what is the alcohol level of the jozo when it’s added to the sake?
30 - 40% abv
what are the possible effect on the style of the final sake by adding jozo alcohol?
- increased expression of aromas (esp. for ginjo)
- lighter palate (lower sugar, acidity and umami)
- lighter body
- shorter and cleaner, crisper finish (kire)
does adding jozo alcohol increase the alcohol strength in the case of premium sake?
no, water is almost always added after filtration to adjust the abv to normal (non-genshu)
why adding jozo alcohol can increase the expression of aromas in premium sakes, especially the gijno style?
- many aromatic compounds are more soluble in alcohol than in water
- increase the alcohol at the filtration stage can extract more of these aroma compounds
- especially those fruity esters
if water is added back after jozo addition, what are the effects to the sake’s flavour profile?
- overall effect is dilution
- lighter body: sweetness, acidity and dextrins are diluted
- some aroma and flavours are lighter, some are increased due to alcohol solvent
- result a lighter, leaner, purer, more elegant style
why the usage of jozo is decreasing?
- the current markets increasingly prefer junmai styles
- new techniques and yeast can produce more intense ginjo aromas w/o using jozo
what is the purpose of the fouth addition?
adjust the sweetness level of the sake
when is the fouth addition add to the sake?
towards the end of fermentation of aruten sakes
what are the elements in the fouth addition?
koji enzymes, mixed steamed rice and water
what is the other term of “filtration”
pressing
what are the 3 main methods of filtration?
- Yabuta-shibori (assakuki)
- funa-shibori
- fukuro-shibori (drip separation)
what is the original name of the Yabuta machine?
assakuki
describe the Yabuta machine
- an accordion-like machine
- vertical pockets panels filled with porridge-like sake
- inflatable pocket is next to each sake-filled panel
- when the air pockets expand, apply pressure to the sake pockets, liquid sqeezed out through the fabric
- the remaining sake-kasu is hold inside the fabric
- a strong metal frame holds everything in place
what are the advantages of using Yabuta?
- it comes with various sizes, the large one can extra large volumes in just a few hours
- pressure can be adjust precisely, suitable for both basic or premium sake
- can extract slowly, allow separating filtration fractions carefully
- minimum oxidation
what is the effect of applying strong pressure in filtration?
release coarse components from the lees to the sake
is Yabuta popular?
- it’s the industry standard for futsu-shu, junmai and honjozo
- almost all ginjo and daiginjo sakes are now filtered by Yabuta
why funa-shibori is now limited to some premium sake?
because the Yabuta is more popular for almost all kind of sake
describe how funa-shibori work
- fresh sake are filled into long synthetic fabric or cotton bag
- these bags are laid horizontally in a large fune (a wooden or metal tub)
- pressure is applied from above. usually mechanically
- sake run out from the bags through a hole at the bottom of the tub
- the sake solid (kasu) are left inside the bags
how long it takes to use funa-shibori to complete filtration?
2 days
what are the advantages of funa-shibori compare with Yabuta?
- lower pressures create sake with finer texture
- smaller scale allow more precise separations of filtration fractions
what are the sake styles using funa-shibori?
- ginjo
- junmai ginjo
- daiginjo
- junmai daiginjo
what is special about fukuro-shibori comparing with funa-shibori and Yabuta?
- it use no external pressure, solely rely on gravity to filter the sake
describe how fukuro-shibori works?
- fresh sake are filled into small cloth bags (5 - 10 L each)
- bags are hung up, liquid drop through from the bottom of the bags
- all solid matters are hold inside the bags
- sake are normally collected in 18 L glass bottles (to-bin)
what are the advantages of using fukuro-shibori?
- it’s slowest and smallest in scale, allow the most precise separation
- it’s even more gentler than funa-shibori
- it produces the finest textures
what are the disadvantages of using fukuro-shibori
- labour intensive
- time consuming
- limited to super-premium sake only
what is the name of the sake filtered by using fukuro-shibori?
shizuku-zake (drip sake)
what to do with the solid and liquid left behind in the bags after fukuro-shibori?
- it can be filtered again using Yabuta or funa-shibori
why brewers and engineers keep exploring new methods of filtration?
- for improving speed and efficiency
- minimize oxidation
- minimize lose of aromatic freshness
which two filtration methods have the highest exposure to air?
- funa-shibori
- fukuro-shibori
why minimizing oxidation is important to ginjo’s quality?
- ginjo sakes have chemicals indication high level of oxidation
what are the advantages of centrifuge separator
- minimum oxygen exposure
- fast
- avoid evaporation of ginjo aromas
- made with stainless steel, no risk of tainting the sake
describe the arabashiri sake
- the free-run liquid comes out from the filter before pressure is applied
- livelier, with more dissolved CO2
- a little cloudy
- rough texture
- extreme freshness
how brewer emphasis the characters of the arabashiri if released?
- unmatured
- unpasteurised
- seasonal product
- labelled as arabashiri
what if arabashiri is not released as a standalone product?
- blend with other fractions
describe naka-dori/naka-gumi
- the middle fraction
- the highest quality sake
- silkiest texture
- purest aromas
what is to-bin gakoi?
the middle few 18 litre to-bins filling with the naka-dori be selected to bottle separately
describe seme
- the final fraction
- coarse in texture
- less aromatic freshness
- more bitter flavours
- more astringency
why seme has less aromatic freshness?
- the liquid has longer exposure to air
- longer time in contact with the solids and the liquids
why seme has coarse texture?
- near the end of filtration, pressure is increased
- more protein, lipid, unconverted starch fragments are extracted from the sake-kasu
what is sake-kasu
the solid cake left after filtration
what’s inside sake-kasu?
- undissolved rice and yeast
- about 8% alcohol
how sake-kasu is re-purpose?
- it can be eaten
- making shochu
- cooking
- pickling vegetables
what is kasu-buai?
- sake cake ratio
- the ratio by weight of sakekasu to polished rice
what are the factors affecting kasu-buai?
- koji enzymes’ efficiency
- filtration efficiency
why the number of kasu-buai sometimes is put on the label?
brewers are proud of high kasu-buai
typically what is the kasu-buai for daiginjo class?
40 - 60%
typically what is the kasu-buai for futsu-shu?
below 30%
what is the difference of kasu of ginjo and futsu-shu in terms of their texture
- ginjo kasu: wet and spongy
- futsu-shu kasu: thin and hard sheet
Flavors if filtered too early?
Butter from diacetyl
Woodiness from acetaldehyde
4th Addition
The last step in sake fermentation process PRE FILTRATION adding jōzō or rice, water, or koji
futshū-shu are allowed to add sugar, amino acids and acidity
How to add sweetness to futshū-shu
Add glucose or other approved sugars in 4th addition
How to add acidity to futshū-shu
Add permitted organic acid
How to add umami to futshū-shu
Amino acids
Where does the highest quality sake come from in filtration?
Middle fraction
Naka-Dori/Naka Gumi
What are the two more oxidated filtration methods.
fukuro-zuri - bag drip
Funa-shibori - bag pressure (stacked on sides)
