Rice and Starch Flashcards
Which prefecture is Omachi grown?
Okayama
Which prefecture is Yamada-nishiki grown?
Hyōgo
Which prefecture is Gohyakuman-goku grown?
Niigata
Which prefecture is miyami-nishiki mainly grown?
Nagano
Which prefecture is Akita-sake-komachi grown?
Akita
When is Omachi harvested?
Late harvest
When is Gohyakuman-goku harvested?
Early Harvest
When is yamada-nishiki harvested?
Late Harvest
When is miyama-nishiki harvested?
Medium harvest
When is akita-sake-komachi harvested?
Medium harvest
What are the 8 stages of rice growing?
- Preparing the paddy
- Growing seedlings
- Transplanting the seedlings
- Draining and re-flooding the paddy
- Appearance of the ears
- Ripening
- Harvesting
- Drying and removing of the husks
What is the ideal location for a paddy?
In a natural basin. This makes it easier to flood and drain the paddy.
What are the qualities growers need their soil to have?
Gluey substances from plants and animals, high percentages of clay particles, rich in nutrients, free from volcanic ash.
Do growers of sake-specific rice use fertilisers in a similar way to growers of table rice?
No. Growers of sake-specific rice use less fertiliser. Farmers will use fertilisers when the seeds are sown, when they are transplanted and when the ears appear. If they add too much fertiliser the levels of proteins, lipids, vitamins and minerals go up in the grains. This is great for tasty table rice but it can result in undesirable aromas and coarse textures in a sake.
What is the most important component of a fertiliser that is used by a farmer?
Nitrogen
What are the nutrients that are important for the formation of a large shinpaku?
Calcium, silicate, phosphoric acid and potassium
When does growing seedling happen?
March to April
Do most farmers grown their own seedlings?
No, most farmers buy seedlings to be transplanted
When does transplanting seedlings happen?
April to June
When does transplanting the seedlings happen?
April to June
Why is the paddy flooded when the rice is transplanted?
It suppresses weeds
What are the ideal weather conditions between transplanting and the appearance of the ears?
Warm sunny days and cool nights
Why do farmers drain the paddy?
If they do not then any rotting vegetation underwater will disrupt the healthy growth of the rice plants. Draining the field allows the dead vegetation to have access to oxygen and decompose in a way they provide nutrients for the rice
When does the appearance of the ears happen?
Late July to September
Is wind helpful when the ears flower?
No, it can disrupt fertilisation and result in a smaller crop
When does ripening happen?
August to October
Why is a large temperature difference between day and night helpful at this time?
It helps with the formation of the shinpaku
What happens if the temperature is too hot?
The rice becomes too glutinous making it harder to handle in the brewery. Also the grains are likely to have proportionally more protein and are more prone to cracking.
When does harvesting happen?
Late August to November
What happens if the farmer harvests too early?
There are too many green/unripe grains in the crop which can result in undesirable flavours in a sake
What happens if the farmer harvests too late?
The grains are drier and more likely to crack
What is lodging?
A condition when the stems of the rice become too weak to support the weight of the grains.
What weather phenomenon are late ripening rice varieties at greater risk from?
Typhoons.
When do drying and removing the husks happen?
Late August to November
What is the moisture level that rice is dried to and why?
14 - 16%. Above this level grains can rot. Below this level grains are more likely to crack when processed. It is also the agreed standard for weighing rice for trading.
What criteria are used to grade rice?
The moisture level and the percentage of broken, cracked, dead or under-ripe grains. The lower the percentage the better.
What are the 5 parts of a rice grain?
From the outer most layer:
Husk
Bran
Germ
Endosperm
Shinpaku
In sake brewing, which part of the grain is always removed?
Husk, bran and germ
How does the shinpaku differ from the outer layers of the endosperm?
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
What are the stages of starch formation and conversion?
Glucose
Starch molecule formed
Starch molecule wrapped into a granule
Gelatinisation
Enzymatic Hydrolysis
Glucose
What is the straight part of a starch molecule called?
Amylose
What is the branched part of starch called?
Amylopectin
What percentage of amylose is required for starch to be considered non-sticky or non-glutinous?
At least 20%
What happens during gelatinisation and why is it necessary?
The starch granules unravel which makes it possible for enzymes to break the starch back into glucose.
What is a limit dextrin and why is it important in sake brewing?
It is a starch fragment that comes from the points where amylopectin branches. They cannot be broken down by kōji mould enzymes, and give sake its mouthcoating texture.
In sake brewing, when does enzymatic hydrolysis take place?
It takes place at the same time as the alcoholic fermentation.
The aim of polishing is to remove the outer layers of the rice grains. Why is this important?
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.
What is nuka?
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?
10 hours
How long does it take to polish 600kg of rice to 50% seimai-buai?
45 hours
If a grain of rice is polished to 35% seimai-buai, how much of the grain has been removed?
35%
Why does a large grain and a well-defined shinpaku help with polishing?
It makes it easier for the brewers to specifically and only remove the outer parts of the grain. This results in a more efficient use of the rice.
What happens to the rice after it has been polished?
It is rested for three to four weeks to allow the rice to cool and re-absorb some of the moisture lost during polishing
Which step follows polishing, and why is it required?
Washing. It is required to remove any remaining nuka from the polished grains. Traditionally done by hand, this can now be done to the same quality by machine.
What is the aim of soaking?
Increase the moisture content of the rice
What is the ideal moisture level of the grains after soaking?
30 - 35%
If the moisture level of the grains is too high, what will happen during fermentation?
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.
Does rice with a polishing ratio of 70% need to be carefully managed during soaking?
No. It absorbs water more slowly and, once a moisture level of 30% is reached, very little extra water is absorbed.
During soaking, how does rice with a low polishing ratio behave differently to rice with a high polishing ratio?
It will continue to absorb water once the moisture level has reached 30%.
What techniques can be used by a brewer in order to achieve the correct moisture level when soaking rice with a low polishing ratio?
Soaking the rice in small batches
using cold water (it is absorbed more slowly)
timing the soaking using a stopwatch.
What is the final stage of rice preparation?
Steaming
What are the aims of steaming?
Sterilise the starch
Gelatinise the starch
Increase the moisture of the rice to around 40%
How is rice loaded into a traditional batch steamer?
It is loaded in layers separated by cloths. This makes it easier to unload the steamer
Where is rice that is to be used in kōji making placed in a traditional batch steamer?
At the top of the
How can a brewer reduce the risk of rice absorbing too much moisture when it is in a traditional batch steamer?
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.
How long does it take rice to be steamed in a traditional batch steamer? How does this compare to a continuous steamer?
700 kilograms of rice are steamed in 40-60 minutes. In a continuous steamer, rice is both steamed and cooled in 30-40 minutes.
