Sake Rice Preparation Flashcards
Understanding Sake: Explaining Style & Quality Chapter 8
What is the moisture content of rice that allows it to be stored for weeks or months?
15%
What are the three things that the brewer needs to achieve during rice preparation?
- reduce the levels of proteins, lipids, vitamins and minerals in the grain that can lead to fast fermentation
- adjust the amount and distribution of moisture in the rice grain to allow the kōji to reach the heart of the grain and for it to break up evenly
- to gelatinise the starch so that the kōji enzymes can break the starch into sugar
What does an overabundance of proteins, lipids, vitamins and minerals cause?
- accelerates kōji production
- accelerates fermentation
High levels of sugar and fast, active fermentations make it difficult to achieve the cool temperatures required to develop precise and elegant flavours.
How is rice polished?
Mechanically, with a high speed rotating roller. The modern vertical rice-polishing machine was first developed in the 1930s and was widespread by the 1980s (ginjō boom)
The historic method is by hand or by a watermill - rice could not be polished under 60% by these methods
What is the nuka?
Rice powder produced by polishing
How long does it take 600kg of brown rice to be polished to 70%?
10 hours
How long does it take 600kg of brown rice to be polished to 50%?
45 hours
What happens after the seimai-buai is reached but before the rice is washed?
Cooling
The cooling process can take three to four weeks.
The rice is allowed to cool down and absorb some of the moisture that was lost during the polishing process. This prevents the rice from cracking when it is washed.
When the rice is soaked during the preparation process, what is the ideal moisture content?
30-35%
The amount depends on the variety, seimai-buai, if it’s intended for kōji or not.
Why is excessive rice soaking bad for the the final product?
If the rice is destined to be kōji, the mould will grow too quickly and not produce the appropriate levels of enzymes.
If the rice is intended for the fermentation, it will break up into the liquid too quickly, allowing for too much sugar in the fermentation and not enough flavours produced (a particular problem for ginjō and daiginjō styles)
What is the temperature of the water used for soaking the rice?
8-15°C
Cooler water is absorbed more slowly
Why would 70% rice be soaked for longer and with less precision than 50% rice?
70% starts off with more natural moisture and absorbs moisture slowly. After a few hours, it reaches 30% and very little extra water is absorbed. Thus it can be soaked in larger batches and with less precise management.
50% starts off drier and absorbs moisture quickly. If left to soak it will absorb more than 30% very easily. Ginjō styles also require more precision in the levels and distribution of moisture.
What are the three techniques the brewer can use to manage moisture levels during the soaking process?
- soak the rice in very small batches
- use cold water to slow absorption
- time the soaking with a stopwatch
After soaking, how quickly is the rice moved to the steamer?
The rice must be drained completely, usually rested for several hours or overnight.
The soaked rice is steamed within 24 hours.
What is are the two purposes of steaming the rice?
- Sterilisation
- Alters the structure of the starch molecules
Steaming also increases moisture content from 30% to 40%
