Filtration

Question 1

Name the 3 types of filtration

Answer 1

1. Yabuta-shibori (Assakuki)
2. Funa-shibori
3. Fukuro-shibori

Question 2

Name 4 advantages of Yabuta-shibori

Answer 2

1. Efficient. Can extract large amounts in a few hours.
2. Flexible. Can be used for all types of sake grades. Air pressure can be adjusted according to grade of sake produced.
3. Good at minimising oxidation.
4. Lower remnants of Kasu.

Question 3

How long does Funa-shibori take?

Answer 3

About 2 days

Question 4

Name 2 advantages of Funa-shibori

Answer 4

1. Lower pressure results in sake with finer texture
2. Smaller scale leads to more precise separation of filtration fractions.

Mainly for Ginjo grade & some Daiginjo grade

Question 5

Name 2 advantages of Fukuro-shibori

Answer 5

1. More gentle than Funa-shibori leading to even finer textures
2. Most precise separation of filtration fractions.

Used for super premium Daiginjo grade or competition.

Remainder of bags can be used in Funa-shibori

Question 6

Name 3 disadvantages of Funa-shibori & Fukuro-shibori

Answer 6

1. Labour intensive
2. Time consuming
3. Oxidation

Question 7

Name the vessel used in Funa-Shibori

Answer 7

Fune

Question 8

Name the vessel used to store sake after Fukuro-shibori

Answer 8

Glass to-bin. Each being 18L

Question 9

Name the 3 filtration factions

Answer 9

1. Arabashiri
2. Naka-dori/naka-gumi
3. Seme

Question 10

Name 3 characteristics of Arabashiri sake

Answer 10

1. Livelier with carbon dioxide which can dissipate over time
2. Can be a little cloudy & rough textured
3. Extreme assertive freshness

Some brewers release this as unmatured, unpasteurised seasonal sakes to maximise the fresh character.

Question 11

Name 3 characteristics of Naka-dori/Naka-gumi sake

Answer 11

1. Highest quality
2. Silkiest texture
3. Purest aromas

No legal definition. Based on toji choice

Question 12

Name 2 characteristics of Seme sake

Answer 12

1. Coarser in texture than Naka-dori
2. Less aromatic freshness because of longer exposure to oxygen

Question 13

What is sake-kasu?

Answer 13

• Solid cake left over from filtration
• Contains undissolved rice, yeast & about 8% abv

Question 14

What can sake-kasu be used for?

Answer 14

• Can be eaten on it’s own
• Raw ingredient for making shochu
• Cooking
• Pickling vegetables

Question 15

What is kasu-buai?

Answer 15

Ratio of mass of sake-kasu as a % of mass of polished rice used to make the sake

Question 16

Name 2 ways that lead to higher kasu-buai

Answer 16

1. Ginjo ferments (low level of koji enzymes & low temp ferment)
2. Very gentle filtration (Fukuro-shibori)

Question 17

Name 2 ways that lead to lower kasu-buai

Answer 17

1. Non ginjo ferment (large amounts of koji enzymes & higher fermentation temp)
2. Very efficient filtration methods (Yabuta-shibori)

Question 18

Describe Yabuta Shibori in 5 steps

Answer 18

1. Sake mash is pumped into vertical pocket panels
2. In between these pocket panels, another pocket can be inflated with air mechanically.
3. Air pockets expand, applying pressure
4. Squeezing the liquid through the fabric
5. A strong metal frame hold everything in place.

Question 19

Describe Funa Shibori in 5 steps

Answer 19

1. Takes 2 days
2. Finished sake mash is poured into long cloth bags
3. Subsequently laid horizontally in a large tub called Fune.
4. Pressure applied mechanically
5. Sake flows out of bags, while solids remain

Question 20

Describe Fukuro Shibori in 5 steps

Answer 20

1. Traditional method
2. Uses no external pressure, relying solely on gravity
3. Finished sake mash is poured into small cloth bags
4. Hung up allowing liquid to flow through.
5. Liquid usually collected in a to-bin (18L)