EXAM COMPLETE QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
Q. Which kind of criteria are used to grade rice? - ANSWER the moisture level and the
percentage of broken, cracked, dead or under-ripe grains. The lower the percentage the
better.
Q. In sake brewing, which part of the grain is always removed? - ANSWER Husk, bran
and germ.
Q. How does the shinpaku differ from the outer layers of the endosperm? - ANSWER
The shinpaku is almost completely pure starch whereas the outer layers of the
endosperm include more other components such as protein, lipids, vitamins and
minerals.
Q. The aim of polishing is to remove the outer layers of the rice grains. Why is this
important? - ANSWER The outer layers include high levels of proteins, lipids, vitamins
and minerals and too much of these would cause the kōji mould and yeast to grow too
quickly. This makes it impossible to have a slow and cool fermentation, which is
required for the generation of the aromas required in sake. Also, too much protein
results in too much umami and coarse textures in the final sake.
Q. What is nuka? - ANSWER This is the powdered outer layers of rice that is created
during polishing.
How long does it take to polish 600kg of rice to 70% seimai-buai? - ANSWER 10 hours.
Q. How long does it take to polish 600kg of rice to 50% seimai-buai? - ANSWER 45
hours.
Q. If a grain of rice is polished to 35% seimai-buai, how much of the grain has been
removed? - ANSWER 65%
Q. Why does a large grain and a well-defined shinpaku help with polishing? - ANSWER
It makes it easier for the brewer to specifically and only remove the outer parts of the
grain. This results in a more efficient use of the rice.
Q. What happens to the rice after it has been polished? - ANSWER It is rested for three
to four weeks to allow the rice to cool and re-absorb some of the moisture lost during
polishing.
Q. What is the ideal moisture level of the grains after soaking? - ANSWER 30-35%
, Q. If the moisture level of the grains is too high, what will happen during fermentation? -
ANSWER If the moisture level of the grains is too high, the rice is not suitable to be
used in the kōji production. The high moisture level will cause the mould to grow too
quickly and create too many enzymes. The highly moist rice is also not suitable to be
added to a fermentation batch because it will make the fermentation process become
more difficult to control. This is due to the fact that the rice will break up too quickly,
resulting in faster enzymatic digestion, creating more sugar and accelerating the
fermentation process.
Q. Does rice with a polishing ratio of 70% need to be carefully managed during
soaking? - ANSWER No. It absorbs water more slowly and, once a moisture level of
30% is reached, very little extra water is absorbed.
Q. What techniques can be used by a brewer in order to achieve the correct moisture
level when soaking rice with a low polishing ratio? - ANSWER Soaking the rice in small
batches, using cold water (it is absorbed more slowly), timing the soaking using a
stopwatch.
Q. What are the aims of steaming? - ANSWER Sterilise the starch, gelatinise the starch
and increase the moisture of the rice to around 40%.
Q. How is rice loaded into a traditional batch steamer? - ANSWER It is loaded in layers
separated by cloths. This makes it easier to unload the steamer.
Q. Where is rice that is to be used in kōji making placed in a traditional batch steamer?
- ANSWER At the top.
Q. How can a brewer reduce the risk of rice absorbing too much moisture when it is in
a traditional batch steamer? - ANSWER Use 'fake rice' at the bottom of the steamer,
cover the steamer with a cloth to stop condensation dripping onto the rice. Use steam
that has a lower concentration of water droplets in it.
Q. How long does it take rice to be steamed in a traditional batch steamer? How does
this compare to a continuous steamer? - ANSWER 700 kilograms of rice are steamed in
40-60 minutes. In a continuous steamer, rice is both steamed and cooled in 30-40
minutes.
Q. Name the three main amylases that are produced by Kōji mould? - ANSWER alpha-
amylase, glucoamylase, alpha-glucosidase
Q. So-haze Kōji has high levels of ... - ANSWER enzymes, vitamins, sugars, amino
acids, fatty acids, and peptides