Kōji Flashcards
What is kōji?
Steamed rice (or barley or other types of grain) inoculated with kōji-kin fungus.
What does kōji do?
It creates enzymes that convert rice starch into fermentable sugar. Kōji also produces other enzymes that break down protein and produces amino acids and peptides.
what are the three categories of kōji-kin?
- Ki-kōjo-kin -yellow
- Shiro-kōji-kin - white
- Kuro-kōji-kin - black
Which type of kōji-kin is used primarily for sake?
Ki-kōji-kin
What are the two types of tane-kōji?
Granulated and powdered
Granulated tane-kōji is most frequently used for what type of sake?
Ginjo
How long does it take to make koji?
40-48 hours.
About how frequently is the temperature checked during koji making?
2 hours, day and night
Describe so-haze
The koji spore covers the entire rice grain sending many hyphae growing into the kernel.
Describe tsuki-haze
The koji spores grow in a lightly spotted pattern over the rice grain with fewer hyphae growing into the kernel.
Which style has a lower vitamin and fatty acid content, so-haze or tsuki-haze?
Tsuki-haze
Which style dissolves the rice well and promotes strong fermentation.
So-haze or tsuki-haze?
So-haze
Tsuki-haze results in sake that is fuller-bodied.
T or F
False
During koji making, what is created besides glucose?
vitamins, amino acids, peptides, malic acid, succinic acid.
List the seven steps of the Koji making process.
- Bringing in
- Spread seed
- Re-breaking up
- Mounding
- Middle Work
- Final Work
- Sending Out
During what hours does Bringing In occur?
0 hours
During what hours does Spread Seed occur?
hours 2-3
During what hours does Re-breaking Up occur?
hours 10-12
During what hours does Mounding occur?
hours 20-23
During what hours does Middle Work occur?
hours 30-33
During what hours does Final Work occur?
hours 36-38
During what hours does Sending Our occur?
hours 44-48
During Koji propagation, what other flavour-influencing components aside from glucose are created?
vitamins, amino acids, pepties, malic acid, succinic acid, and others.
Describe Futa-koji
The koji-innoculated rice is moved to futa, smaller containes resembling lids or trays. The separating allows the humidity and temperatures of the rice to become more even, The brewers can shift the locations and layers everty 3 hours or so. This method handles 1.5 kg to 2.5 kg of rice. Used for higher grade, expensive sake.
Describe Hako-Koji
Box koji - This method is commonly used for a wider range of sake. It is a simplified version of Futa-Koji. The brewer puts the rice into large boxes, futa, split with a divider that can slide from side to side to control the release of temperature. Handles 15 kg to 40 kg of rice.
Describe Toko-koji
Steamed rice is placed on a special table, the toko. This method allows for a large volume of rice but does not allow for precise manipulation. Primarily used for futsushu.
Middle Work is what step and takes place at what temperature?
Step 5 of 7; 35C
Spread Seed is what step?
2 of 7
Final Work is what step and what temperature?
6 of 7; It doesn’t begin until reaching 38C and it is kept under 43C.
What is the 3rd step of Koji making?
Re-breaking up. The temperature increases to 33C. Rice is mixed well to even the temperature and cool it to 31C.
How long does koji-kin normally take to form?
- Six hours
- One day
- Two to three days
- One week
- Two to three days
What are the ideal conditions for koji mould growth?
High humidity and temperatures between 33C and 38C (92F-100F).
What are the four stages of koji making?
- Cooling the steamed rice to the right temperature
- Innoculating the rice with koji spores
- Initial mould growth
- Controlling and stopping the mould growth.
How is mould growth stopped?
The rice is moved to the coolest and driest part of the koji room.
What is the look / feel / taste of koji rice?
Look: Koji rice looks like polished rice
Feel: Koji rice has a crumby texture
Taste: Koji rice has a slightly sweet chestnut flavour
What are limit dextrans?
Limit dextrans are portions of the starch that the koji enzymes could not break into glucose. They are important because they provide sake’s characteristic rich mouthfeel.
