User:Jyan12/sandbox

For our assignment on Sake, we are aiming to explore subtopics such as fermentation methods/manufacturing techniques and chemical compounds used in the production of Sake.

Some reliable and neutral sources of information we plan to use for our project are: 1) https://sake-world.com/about-sake/how-sake-is-made/sake-brewing-process/ 2) http://www.japansake.or.jp/sake/english/howto/process.html 3) https://www.nrib.go.jp/English/sake/ss/sshm_shubo.htm

Final Draft of Project (also posted in the Sake Wikipedia page):

Kōji-kin

Kōji-kin (Aspergillus oryzae) spores are another important component of sake. Kōji-kin is an enzyme-secreting fungus.^[15] In Japan, kōji-kin is used to make various fermented foods, including miso (a paste made from soybeans) and shoyu (soy sauce).^[15] It is also used to make alcoholic beverages, notably sake.^[15] During sake brewing, spores of kōji-kin are scattered over steamed rice to produce kōji (rice in which kōji-kin spores are cultivated).^[16] Under warm and moist conditions, the kōji-kin spores germinate and release enzymes called amylases that convert the starches in the steamed rice into glucose.^[17] This process of starch conversion into simpler sugars (e.g. glucose, maltose) is called saccharification.^[18] Yeasts then turn this glucose into alcohol via fermentation.^[16] Saccharification also occurs in beer brewing, where malt is used to convert starch from barley into maltose.^[16] However, whereas fermentation occurs after saccharification in beer brewing, saccharification (via kōji-kin) and fermentation (via yeast) occur simultaneously in sake brewing (see "Fermentation" below).^[16]

As kōji-kin is a microorganism used to manufacture food, its safety profile with respect to humans and the environment in sake brewing and other food-making processes must be considered. Various health authorities, including Health Canada and the U.S. Food and Drug Administration (FDA), consider kōji-kin (A. oryzae) generally safe for use in food fermentation, including sake brewing.^[15] When assessing its safety, it is important to note that A. oryzae lacks the ability to produce toxins, unlike the closely related Aspergillus flavus.^[15] To date, there have been only several reported cases of animals (e.g. parrots, a horse) being infected with A. oryzae.^[19] In these cases, however, the animals infected with A. oryzae were already weakened due to predisposing conditions like recent injury, illness, or stress, and were therefore especially susceptible to infections in general.^[19] Aside from these cases, there is no evidence to indicate A. oryzae is a harmful pathogen to either plants or animals in the scientific literature.^[19]Therefore, Health Canada considers A. oryzae “unlikely to be a serious hazard to livestock or to other organisms,” including "healthy or debilitated humans."^[19] Given its safety record in the scientific literature and extensive history of safe use (spanning several hundred years) in the Japanese food industry, the FDA and World Health Organization (WHO) also support the safety of A. oryzae for use in the production of foods like sake.^[15] In the U.S., the FDA classifies A.oryzae as a Generally Recognized as Safe (GRAS) organism.^[15]

Fermentation

Moromi (the main fermenting mash) undergoing fermentation

Sake fermentation is a 3-step process called sandan shikomi.^[20] The first step, called hatsuzoe, involves the steamed rice, water, and kōji-kin being added to the yeast starter called shubo, which is made from a mixture of steamed rice, water, kōji, and yeast.^[20] This mixture becomes known as the moromi (the main mash during sake fermentation).^[20]The high yeast content of the shubo promotes the fermentation of the moromi.^[20]

On the second day, the mixture is left to stand for a day to allow the yeast to multiply.^[20]

The second step (the third day of the process), called nakazoe, involves the addition of a second batch of kōji, steamed rice, and water to the mixture.^[20] On the fourth day of the fermentation, the third step of the process, called tomezoe, takes place.^[20] Here, the third and final batch of kōji, steamed rice, and water is added to the mixture to complete the 3-step process.^[20]

The fermentation process of sake is a multiple parallel fermentation, which is unique to sake.^[20] Multiple parallel fermentation is the conversion of starch into glucose followed by immediate conversion into alcohol.^[21] This process distinguishes sake from other liquors like beer because it occurs in a single vat, whereas with beer, for instance, starch to glucose conversion and glucose to alcohol conversion occur in separate vats.^[21] The breakdown of starch into glucose is caused by the kōji-kin fungus, while the conversion of glucose into alcohol is caused by yeast.^[21] Due to the yeast being available as soon as the glucose is produced, the conversion of glucose to alcohol is very efficient in sake brewing.^[21] This results in sake having a generally higher alcohol content than other types of liquor.^[21]

After the fermentation process is complete, the fermented moromi is pushed through a press to remove the sake lees and then pasteurized and filtered for color.^[20] The sake is then stored in bottles under cold conditions (see "Maturation" below).^[20]

The entire process of making sake can range from 60-90 days (2-3 months), while the fermentation alone can take two weeks.^[22]