- Fermentation type(s)
The various patterns of sake fermentation are usually described in terms of eight categories.
Note: the styles of fermentation are described using the following characters.
急 (pronounced kyu (with a long “u”) – indicating hurry, and used to describe a fast, vigorous phase
緩 (kan) – meaning slow or gentle
平 (hei) – meaning flat or even
前 (zen) – before or beginning – early stages of fermentation
後 (ko (long “o”)) – after or end – referring to the later stages of fermentation
高温 (ko- (long “o”) on) – high temperature
低温 (tei-on) – low temperature
短期 (tanki) – short (period)
長期 (choki (long “o”) – long (period)
NB: Pronunciation of these characters is different in other contexts and combinations.
- Zenkyu kokan (前急後緩, “fast beginning, slow later”).
Tends to higher temperatures in the early stages, with temperature declining rather in the later phase. Acidity (san-do) tends to be low, and colour pale.
- Zenkyu kokyu (前急後急, “fast beginning, fast later”).
The early stages similar to 1., but with fast fermentation continuing in the later stages. Gives sake low in sweetness.
- Zenkan kokyu (前緩後急, ”slow beginning, fast later”).
Moromi with a gentle fermentation to begin, but high temperature and vigorous fermentation later on. Although the flavour of the finished sake improves with age, it tends to be rough-tasting, darkly coloured, and high in acidity.
- Zenkan kokan (前緩後緩, “slow beginning, slow later”).
Low temperatures in the early stages rise somewhat later, but are generally on the low side overall. Fermentation time (moromi nissu) is long, and large quantities of remaining sake kasu, and sweeter sake, are often the end result.
- Zenkyu kohei (前急後平, “fast beginning, level later”).
The later stages of fermentation rather livelier than for 1.; an ideal progression.
- Zenkan kohei (前緩後平, “slow beginning, level later”).
With a rather slower second half than 3., but overall slightly faster than 4., this pattern is not much seen.
- Ko-on tanki (高温短期, “high temperature short-term”).
High-temperature moromi with short fermentation time.
- Tei-on choki (低温長期, “low temperature long-term”).
Low temperatures and long fermentation time.