Editing Sake (section)

==Production==
[[File:Brasserie de saké Takayama.jpg|thumb|Sake brewery in [[Takayama, Gifu|Takayama]], with a ''[[sugidama]]'' globe of [[Cryptomeria|cedar]] leaves indicating new sake]]
===Rice===
[[File:Yamada Nishiki rice (unpolished) from Hyogo.jpg|thumb|[[Yamada Nishiki]]]]
The rice used for brewing sake is called {{Nihongo3|'sake rice'|酒米, さかまい|sakamai}}, or officially {{Nihongo3|'sake-brewing suitable rice'|酒造好適米, しゅぞうこうてきまい|shuzō kōtekimai}}.<ref>{{Cite web|title=A handy guide to sake - Japan's national drink|url=https://japantoday.com/category/features/food/a-handy-guide-to-sake-japan%27s-national-drink|access-date=2021-11-23|website=Japan Today|language=en}}</ref> There are at least 123 types of sake rice in Japan.<ref name ="nourin">{{cite web|url=https://www.maff.go.jp/j/seisaku_tokatu/kikaku/attach/pdf/sake_01chousa-1.pdf|archive-url=https://web.archive.org/web/20221215083805/https://www.maff.go.jp/j/seisaku_tokatu/kikaku/attach/pdf/sake_01chousa-1.pdf|script-title=ja:資料2 酒造好適米の農産物検査結果（生産量）と令和元年産の生産量推計（銘柄別）|language=ja|publisher=[[Ministry of Agriculture, Forestry and Fisheries (Japan)]]|archive-date=15 December 2022}}</ref> Among these, [[Yamada Nishiki]], Gohyakumangoku, Miyama Nishiki and Omachi rice are popular.<ref name ="nourin"/> The grain is larger, stronger (if a grain is small or weak, it will break in the process of polishing), and contains less protein and lipid than ordinary table rice. Because of the cost, ordinary table rice, which is cheaper than sake rice, is sometimes used for sake brewing, but because sake rice has been improved and optimized for sake brewing, few people eat it.<ref name="yamada">{{cite web|url=http://www.nippon.com/ja/features/h00113/|archive-url=https://web.archive.org/web/20170625030216/http://www.nippon.com/ja/features/h00113/|script-title=ja:酒米の王様「山田錦」|language=ja|publisher=Nippon.com|date=19 June 2015|archive-date=25 June 2017}}</ref><ref name="nihonshula">{{cite web|url=https://sake-5.jp/rice-polishing-rate/|archive-url=https://web.archive.org/web/20220519091409/https://sake-5.jp/rice-polishing-rate/|script-title=ja: 日本酒の精米歩合について詳しく解説 精米歩合が高い=良いお米？|language=ja|publisher=Nihonshu Lab|date=18 September 2020|archive-date=19 May 2022}}</ref>

Premium sake is mostly made from sake rice. However, non-premium sake is mostly made from table rice. According to the Japan Sake and Shochu Makers Association, premium sake makes up 25% of total sake production, and non-premium sake ({{tlit|ja|futsushu}}) makes up 75% of sake production. In 2008, a total of 180,000 tons of polished rice were used in sake brewing, of which sake rice accounted for 44,000 tons (24%), and table rice accounted for 136,000 tons (76%).<ref>Page 15 and 37 https://www.nrib.go.jp/English/sake/pdf/guidesse01.pdf {{Webarchive|url=https://web.archive.org/web/20201111191207/https://www.nrib.go.jp/English/sake/pdf/guidesse01.pdf |date=November 11, 2020 }}</ref>

Sake rice is usually polished to a much higher degree than ordinary table rice. The reason for polishing is a result of the composition and structure of the rice grain itself. The core of the rice grain is rich in starch, while the outer layers of the grain contain higher concentrations of fats, vitamins, and proteins. Since a higher concentration of fat and protein in the sake would lead to off-flavors and contribute rough elements to the sake, the outer layers of the sake rice grain is milled away in a polishing process, leaving only the starchy part of the grain (some sake brewers remove over 60% of the rice grain in the polishing process). That desirable pocket of starch in the center of the grain is called the {{Nihongo||心白, しんぱく|shinpaku}}. It usually takes two to three days to polish rice down to less than half its original size. The rice powder by-product of polishing is often used for making [[Rice cracker|rice crackers]], Japanese sweets (i.e. [[Dango]]), and other food stuffs.<ref name="yamada"/><ref name="nihonshula"/>

If the sake is made with rice with a higher percentage of its husk and the outer portion of the core milled off, then more rice will be required to make that particular sake, which will take longer to produce. Thus, sake made with rice that has been highly milled is usually more expensive than sake that has been made with less-polished rice. This does not always mean that sake made with highly milled rice is of better quality than sake made with rice milled less. Sake made with highly milled rice has a strong aroma and a light taste without miscellaneous taste. It maximizes the fruity flavor of ''[[#Special-designation sake|ginjō]]''. On the other hand, sake made with less milled rice but with attention to various factors tends to have a rich sweetness and flavor derived from rice.<ref name="yamada"/><ref name="nihonshula"/>

''Rice polishing ratio'', called {{Nihongo||精米歩合, せいまいぶあい|Seimai-buai}} (see [[Glossary of sake terms]]) measures the degree of rice polishing. For example, a rice polishing ratio of 70% means that 70% of the original rice grain remains and 30% has been polished away.<ref>{{Cite news|last=Mathew|first=Sunalini|date=2019-01-03|title=Introducing sake|language=en-IN|work=The Hindu|url=https://www.thehindu.com/life-and-style/food/introducing-sake/article25899194.ece|access-date=2021-11-23|issn=0971-751X}}</ref> As of 2023, the most polished sake has a polishing ratio of 0.85% or less, with at least 99.15% of its rice grains polished away. This sake is {{nihongo||零響 Crystal 0|Reikyo Crystal 0}}, released by {{nihongo|Niizawa Brewery Co.|新澤醸造店}}, priced at 1,375,000 yen for 720 ml.<ref>{{cite web|url=https://xtrend.nikkei.com/atcl/contents/18/00765/00003/|archive-url=https://web.archive.org/web/20230127134216/https://xtrend.nikkei.com/atcl/contents/18/00765/00003/?n_cid=nbpnxr_twed_new|script-title=ja:日本酒の世界最高精米歩合、ついに更新 新澤醸造店が目指す新地平|language=ja|publisher=Nikkei Business Publications, Inc.|date=24 January 2023|archive-date=27 January 2023}}</ref>

===Water===
Water is involved in almost every major sake brewing process, from washing the rice to diluting the final product before bottling.  The mineral content of the water can be important in the final product. [[Iron]] will bond with an [[amino acid]] produced by the {{tlit|ja|kōji}} to produce off flavors and a yellowish color. [[Manganese]], when exposed to ultraviolet light, will also contribute to discoloration.  Conversely, [[potassium]], [[magnesium]], and [[phosphoric acid]] serve as nutrients for sake yeast during fermentation and are considered desirable.<ref name=water>{{cite web|last=Gauntner|first=John|title=How Sake Is Made|date=September 30, 2014|url=http://sake-world.com/about-sake/how-sake-is-made/the-water/|publisher=Sake World|access-date=January 1, 2016}}</ref>  The yeast will use those nutrients to work faster and multiply resulting in more sugar being converted into alcohol. While soft water will typically yield sweeter sake, hard water with a higher mineral content is known for producing [[Dryness (taste)|drier-style]] sake.

The first region known for having great water was the [[Nada-Gogō]] in [[Hyōgo Prefecture]]. A particular water source called {{tlit|ja|Miyamizu}} was found to produce high-quality sake and attracted many producers to the region.

Typically breweries obtain water from wells, though surface water can be used.  Breweries may use tap water and filter and adjust components.<ref name=water />

=== ''Kōji-kin'' ===
==== ''Aspergillus oryzae'' (yellow ''kōji'') ====
''[[Aspergillus oryzae]]'' spores are another important component of sake. ''A. oryzae'' is an enzyme-secreting [[fungus]].<ref name="Machida-2008">{{Cite journal|last1=Machida|first1=Masayuki|last2=Yamada|first2=Osamu|last3=Gomi|first3=Katsuya|date=August 2008|title=Genomics of Aspergillus oryzae: Learning from the History of Koji Mold and Exploration of Its Future|journal=DNA Research |volume=15|issue=4|pages=173–183|doi=10.1093/dnares/dsn020|issn=1340-2838|pmc=2575883|pmid=18820080}}</ref> In Japan, ''A. oryzae'' is used to make various fermented foods, including ''[[miso]]'' (a paste made from soybeans) and {{Nihongo3|||shoyu}} ([[soy sauce]]).<ref name="Machida-2008" /> It is also used to make alcoholic beverages, notably sake.<ref name="Machida-2008" /> During sake brewing, spores of ''A. oryzae'' are scattered over steamed [[rice]] to produce {{Nihongo3|||kōji}} (rice in which ''A. oryzae'' spores are cultivated).<ref name="Tengu Sake">{{Cite web|url=https://www.tengusake.com/sake-guide/how-sake-is-made/|title=How sake is made|website=Tengu Sake|language=en-GB|access-date=2019-08-08}}</ref> Under warm and moist conditions, the ''A. oryzae'' spores germinate and release [[amylase]]s (enzymes that convert the rice [[starch]]es into maltose and glucose). This conversion of starch into simple sugars (e.g., glucose or maltose) is called [[saccharification]]. Yeast then [[fermentation|ferment]] the glucose and other sugar into [[ethanol|alcohol]].<ref name="Tengu Sake" /> Saccharification also occurs in [[beer]] brewing, where [[mashing]] is used to convert starches from [[barley]] into maltose.<ref name="Tengu Sake" /> However, whereas fermentation occurs ''after'' saccharification in beer brewing, saccharification (via ''A. oryzae'') and fermentation (via yeast) occur ''simultaneously'' in sake brewing (see "Fermentation" below).<ref name="Tengu Sake" />

As ''A. oryzae'' is a microorganism used to manufacture food, its safety profile concerning humans and the environment in sake brewing and other food-making processes must be considered. Various health authorities, including [[Health Canada]] and the [[United States|U.S.]] [[Food and Drug Administration]] (FDA), consider ''A. oryzae'' generally safe for use in food fermentation, including sake brewing.<ref name="Machida-2008" /> When assessing its safety, it is important to note that ''A.'' ''oryzae'' lacks the ability to produce toxins, unlike the closely related ''[[Aspergillus flavus]]''.<ref name="Machida-2008" /> To date, there have been several reported cases of animals (e.g. [[parrot]]s, a [[horse]]) being infected with ''A. oryzae''.<ref name="Government of Canada-2017">{{Cite web|url=http://publications.gc.ca/site/archivee-archived.html?url=http://publications.gc.ca/collections/collection_2017/eccc/En14-267-2017-eng.pdf|title=Final Screening Assessment for ''Aspergillus oryzae'' ATCC 11866 |date=January 2017 |last=Government of Canada |access-date=2019-08-08|archive-url=https://web.archive.org/web/20191023170107/http://publications.gc.ca/collections/collection_2017/eccc/En14-267-2017-eng.pdf |archive-date=Oct 23, 2019 |url-status=dead}}</ref> In these cases the animals infected with ''A. oryzae'' were already weakened due to predisposing conditions such as recent injury, illness or stress, hence were susceptible to infections in general.<ref name="Government of Canada-2017" /> 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.<ref name="Government of Canada-2017" /> Therefore, Health Canada considers ''A. oryzae'' "unlikely to be a serious hazard to [[livestock]] or to other organisms," including "healthy or debilitated humans."<ref name="Government of Canada-2017" /> 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.<ref name="Machida-2008" /> In the US, the FDA classifies ''A.oryzae'' as a [[Generally recognized as safe|Generally Recognized as Safe]] (GRAS) organism.<ref name="Machida-2008" />

==== ''Aspergillus kawachii'' (white ''kōji'') ====
In addition to ''Aspergillus oryzae'' (yellow ''kōji''), ''Aspergillus kawachii'' (white ''kōji'') and ''Aspergillus luchuensis'' (black ''kōji''), which are used to brew ''[[shōchū]]'' and ''[[awamori]]'', have been used to brew sake since the 21st century.<ref name="kawachii220520">{{cite web|url=https://sakestreet.com/ja/media/learn-shiro-koji-and-kuro-koji|archive-url=https://web.archive.org/web/20220930061200/https://sakestreet.com/ja/media/learn-shiro-koji-and-kuro-koji|script-title=ja:日本酒造りにもたらされた「クエン酸」による変革!! - 白麹、黒麹仕込みの日本酒を学ぶ|language=ja|publisher=Sake Street|date=22 May 2022|archive-date=30 September 2022|access-date=9 April 2023}}</ref>

From the 1980s, research was conducted to brew sake using ''[[Aspergillus luchuensis|Aspergillus kawachii]]'' (white ''kōji''), which is used to make ''shōchū'',<ref>{{cite journal|url=https://www.jstage.jst.go.jp/article/jbrewsocjapan1988/85/2/85_2_114/_article|archive-url=https://web.archive.org/web/20180605164117/https://www.jstage.jst.go.jp/article/jbrewsocjapan1988/85/2/85_2_114/_article|title=Fermentation Characteristics of Sake Mash made by Using Rice Koji Prepared with Aspergillus kawachii |first1=Akihiro |last1=Nakamura |first2=Naoki |last2=Iimori |first3=Shigetoshi |last3=Sudo |first4=Shigeaki |last4=Mikami |first5=Kiyoshi |last5=Ito |first6=Takeaki |last6=Ishikawa |journal=Journal of the Brewing Society of Japan |volume=85 |date=1990 |issue=2 |pages=114–119 |doi=10.6013/jbrewsocjapan1988.85.114 |doi-access=free |archive-date=5 June 2018|access-date=9 April 2023}}</ref> and sake made with ''Aspergillus kawachii'' became popular when Aramasa Co, Ltd. released "Amaneko" using ''Aspergillus kawachii'' in 2009. ''Aspergillus kawachii'' produces about 10 times more [[citric acid]] than ''Aspergillus oryzae'', and thus has a strong ability to suppress the growth of bacteria that damage the flavor of sake. It also imparts a sour, citrus-like flavor to sake. Because it produces so much citric acid, older sake-making methods such as ''[[#Methods of preparing the starter mash|kimoto]]'' or ''[[#Methods of preparing the starter mash|yamahai]]'' can produce a starter mash as quickly as modern ''[[#Methods of preparing the starter mash|sokujō]]''. ''Kimoto'' and ''yamahai'' do not add artificial lactic acid, which allows them to be labeled "additive-free," giving them a marketing advantage when exporting.<ref name="kawachii220520"/>

==== ''Aspergillus luchuensis'' (black ''kōji'') ====
As of 2022, sake made with ''[[Aspergillus luchuensis]]'' (black ''kōji'') is not as popular as sake made with ''Aspergillus kawachii''. It produces more citric acid than ''Aspergillus kawachii''. However, it produces less [[amino acid|amino acids]], which produce complex flavors such as [[umami]], bitterness, and sweetness. ''Aspergillus luchuensis'' also produces more [[peptide|peptides]], which results in a bitter taste. This combines with a strong sour taste from the citric acid, which is sometimes compared to strawberry or [[red wine]].<ref name="kawachii220520"/>

=== Sake yeast ===
[[File:Sake made with Kyōkai yeast Akairo kōbo for pink nigorizake, 協会酵母清酒用赤色酵母（桃色濁り酒用）.jpg|thumb|150px|Sake made with Kyokai yeast "Akairo kōbo" for pink ''[[nigori|nigorizake]]''<ref name="akairo2"/>]]
Sake [[yeast]] is so important in sake brewing that it is said to affect the flavor of sake more than rice. In sake brewing, ''kōji'' breaks down rice starch into glucose, and yeast is responsible for the fermentation process that converts the glucose into alcohol. Yeast has a significant impact on the flavor of sake by producing [[Ethyl hexanoate|ethyl caproate]], [[isoamyl acetate]], and other flavor compounds and acids as well as alcohol during the fermentation process.<ref name="ss051219">{{Cite web |author=Kohei Ninohe|script-title=ja:実は味の決め手？「酵母」とは - 日本酒造りにおける役割と種類を徹底解説|language=ja|url=https://sakestreet.com/ja/media/learn-yeast-for-sake-1|archive-url=https://web.archive.org/web/20240915004906/https://sakestreet.com/ja/media/learn-yeast-for-sake-1|publisher=SAKE Street, Inc.|date=5 December 2019|archive-date=15 September 2024|access-date=8 February 2025 }}</ref>

The various types of yeast used in sake brewing belong to the species ''[[Saccharomyces cerevisiae]]'', and a large number of yeasts have been developed in Japan.<ref name="ss051219"/> For example, the laboratory of the {{ill|Hakutsuru Sake Brewery|ja|白鶴酒造}} has 400 types of yeast.<ref name="st140120">{{Cite web |author=Akiko Watabe|script-title=ja:400種以上の“自社開発酵母”が日本酒の新たな個性をつくる─ 革新的な商品を次々と生み出す白鶴酒造が培った酵母研究|language=ja|url=https://jp.sake-times.com/special/pr/pr_hakutsuru2_004|archive-url=https://web.archive.org/web/20240910114946/https://jp.sake-times.com/special/pr/pr_hakutsuru2_004|publisher=Sake Times|date=14 January 2020|archive-date=10 September 2024|access-date=8 February 2025 }}</ref>

Before the modernization of Japan, breweries used yeasts that were native to each brewery. The yeasts evolved uniquely in each brewery as they competed for survival by mixing with microorganisms that became airborne and attached to the human body during the sake brewing process. Because some of these yeasts were not suitable for brewing sake, the quality of sake varied from brewery to brewery and from period to period.<ref name="hi0220120">{{Cite web |author=|script-title=ja:日本酒の「酵母」の歴史|language=ja|url=https://harimacountry.com/archives/330|archive-url=https://web.archive.org/web/20240725194628/https://harimacountry.com/archives/330|publisher=[[Himeji|Himeji City]]|date=21 January 2020|archive-date=25 July 2024|access-date=8 February 2025 }}</ref><ref name="as190214">{{Cite web |author=|script-title=ja:酵母の話（1）|language=ja|url=https://www.osake.or.jp/sake/140219.html|archive-url=https://web.archive.org/web/20230908021908/https://www.osake.or.jp/sake/140219.html|publisher=Akita Sake Brewers Association|date=19 February 2014|archive-date=8 September 2023|access-date=8 February 2025 }}</ref><ref name="kt291222">{{Cite web |author=|script-title=ja:酵母の発見～酵母の歴史を巡る～|language=ja|url=https://tc-kyoto.or.jp/magazine/history-kyotokobo-ep02/|archive-url=https://web.archive.org/web/20241005065706/https://tc-kyoto.or.jp/magazine/history-kyotokobo-ep02/|publisher= Kyoto Municipal Institute of Industrial Technology and Culture|date=29 December 2022|archive-date=5 October 2024|access-date=8 February 2025 }}</ref>

In 1895, Dr. Kikuji Yabe isolated the first ''Saccharomyces sake'' yeast suitable for brewing sake. In 1904, the government established the National Brewing Laboratory and began detailed studies of yeast.
In 1906, the Brewing Society of Japan was founded, and a system was established whereby any superior yeast discovered was registered as ''Kyokai-kōbo'' ("Kyokai yeast", "Association yeast") and distributed to breweries throughout Japan. Kyokai yeast No. 7 and No. 9 are particularly popular. In response to the popularity of ''ginjō-shu'' since the 1980s, various aromatic yeasts have been developed. Today, the Brewing Society of Japan, research institutes in each prefecture, and breweries continue to develop a variety of yeasts, and an increasing number of breweries are making sake from yeasts found in flowers.<ref name="hi0220120"/><ref name="as190214"/><ref name="kt291222"/>

Some sake yeasts can also color sake. For example, Kyokai yeast "Akairo kōbo", isolated in 1984, can produce pink ''[[nigori]]'' or ''[[#Different handling after fermentation|origarami]]'' sake by producing a red pigment during fermentation. This yeast is not fertile and temperature control is difficult, but it adds a sweet strawberry flavor to the sake.<ref name="akairo">{{Cite web|script-title=ja:清酒用赤色酵母（桃色濁り酒用）|language=ja|url=https://www.jozo.or.jp/yeast/red/|archive-url=https://web.archive.org/web/20241011234433/https://www.jozo.or.jp/yeast/red/|publisher=The Brewing Society of Japan|date=|archive-date=11 October 2024|access-date=15 February 2025 }}</ref><ref name="akairo2">{{Cite web|script-title=ja:ちえびじん LOVE PINK|language=ja|url=https://www.jizake.com/c/sake/chiebijin/Sake9100_1800|archive-url=https://web.archive.org/web/20240916025032/https://www.jizake.com/c/sake/chiebijin/Sake9100_1800|publisher=The Brewing Society of Japan|date=|archive-date=16 September 2024|access-date=15 February 2025 }}</ref>

=== Fermentation ===
[[File:Moromi.JPG|thumb|{{tlit|ja|Moromi}} (the main fermenting mash) undergoing fermentation|alt=]]

Sake fermentation is a three-step process called {{tlit|ja|sandan shikomi}}.<ref name="JSSMA" /> The first step, called {{tlit|ja|hatsuzoe}}, involves steamed rice, water, and {{tlit|ja|kōji-kin}} being added to the yeast starter called {{tlit|ja|shubo}}: a mixture of steamed rice, water, [[Aspergillus oryzae|kōji]], and yeast.<ref name="JSSMA" /> This mixture becomes known as the {{tlit|ja|moromi}} (the main mash during sake fermentation).<ref name="JSSMA" /> The high yeast content of the {{tlit|ja|shubo}} promotes the fermentation of the {{tlit|ja|moromi}}''.''<ref name="JSSMA">{{Cite web|url=http://www.japansake.or.jp/sake/english/howto/process.html|title=Brewing Process {{!}} How to |website=Japan Sake and Shochu Makers Association |access-date=2019-08-08|archive-date=July 30, 2019|archive-url=https://web.archive.org/web/20190730174108/http://www.japansake.or.jp/sake/english/howto/process.html|url-status=dead}}</ref>

On the second day, the mixture stands for a day to let the yeast multiply.<ref name="JSSMA" />

The second step (the third day of the process), called {{tlit|ja|nakazoe}}, involves the addition of a second batch of {{tlit|ja|kōji}}, steamed rice, and water to the mixture.<ref name="JSSMA" /> On the fourth day of the fermentation, the third step of the process, called {{tlit|ja|tomezoe}}, takes place.<ref name="JSSMA" /> Here, the third and final batch of kōji, steamed rice, and water is added to the mixture, followed by up to ten days or so of additional fermentation to complete the three-step process.<ref name="JSSMA" />

The multiple parallel fermentation process of sake brewing, where starch is converted into glucose followed by immediate conversion into alcohol,<ref name="en-tradition" /> is unique to it.<ref name="JSSMA" /> This distinguishes sake from other brewed alcoholic beverages 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.<ref name="en-tradition" /> The breakdown of starch into glucose is caused by the {{Nihongo3|||kōji-kin}} fungus, while the conversion of glucose into alcohol is caused by yeast.<ref name="en-tradition" /> 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.<ref name="en-tradition" /> This results in sake having a generally higher alcohol content than other types of beer or wine.<ref name="en-tradition">{{Cite web|url=https://en-tradition.com/sake/heikou.html|title=Multiple parallel fermentation: Japanese Sake|website=en-tradition.com|access-date=2019-08-08|archive-url=https://web.archive.org/web/20190808040615/https://en-tradition.com/sake/heikou.html|archive-date=August 8, 2019|url-status=dead}}</ref>

After the fermentation process is complete, the fermented {{tlit|ja|moromi}} is pressed to remove the sake [[Lees (fermentation)|lees]] and then pasteurized and filtered for color.<ref name="JSSMA" /> The sake is then stored in bottles under cold conditions (see "Maturation" below).<ref name="JSSMA" />

The process of making sake can range from 60 to 90 days (2–3 months), while the fermentation alone can take two weeks.<ref>{{Cite web|url=https://sake-world.com/about-sake/how-sake-is-made/sake-brewing-process/|title=Sake brewing process|last=Gauntner|first=John|website=Sake World|date=September 29, 2014|language=en-US|access-date=2019-08-08}}</ref> On the other hand, ''[[#Special-designation sake|ginjō-shu]]'' takes about 30 days for fermentation alone.<ref name="ginjo"/>

=== Maturation ===
Like other brewed beverages, sake tends to benefit from a period of storage. Nine to twelve months are required for the sake to mature. Maturation is caused by physical and chemical factors such as oxygen supply, the broad application of external heat, nitrogen oxides, aldehydes, and amino acids, among other unknown factors.<ref>{{Cite journal|last=National Research Institute of Brewing|date=March 2017|title=Sake Brewing: The Integration of Science and Technology|url=http://www.nrib.go.jp/English/sake/pdf/SakeNo02_en.pdf|journal=The Story of Sake}}</ref>

===''Tōji''===
{{Nihongo||杜氏|Tōji}} is the job title of the sake [[Brewing|brewer]]. There are various theories about the origin of the word, but the most popular is that it is a corruption of the word {{Nihongo||刀自|tōji}}, which was used for housewives and elderly women who supervised ''[[miko]]'' (shrine maidens). This is because sake brewing was the work of housewives at home and ''miko'' at [[Shinto shrine|Shinto shrines]].<ref>{{cite web|url=https://www.osake.or.jp/sake/140312.html|archive-url=https://web.archive.org/web/20220520103254/https://www.osake.or.jp/sake/140312.html|script-title=ja:秋田の杜氏の秘密 杜氏（とうじ）とは|language=ja|publisher=Akita Sake Brewers Association.|date=12 March 2014|archive-date=20 May 2022|access-date=6 February 2023}}</ref><ref>{{cite web|url=https://www.gekkeikan.co.jp/enjoy/sake/industry/industry03.html|archive-url=https://web.archive.org/web/20220705162609/https://www.gekkeikan.co.jp/enjoy/sake/industry/industry03.html|script-title=ja:杜氏と蔵人 杜氏に匹敵する技を持つ蔵元の酒造技能者|language=ja|publisher=[[Gekkeikan]]|archive-date=5 July 2022|access-date=6 February 2023}}</ref><ref>{{cite web|url=https://sakestreet.com/ja/media/what-is-toji|archive-url=https://web.archive.org/web/20220930060512/https://sakestreet.com/ja/media/what-is-toji|script-title=ja:日本酒造りの責任者「杜氏」とは？ - 杜氏の仕事から杜氏の流派 蔵人たちの役職まで|language=ja|publisher=Sake Street|date=11 December 2021|archive-date=30 September 2022|access-date=6 February 2023}}</ref> It is a highly respected job in the [[Culture of Japan|Japanese society]], with {{tlit|ja|tōji}} being regarded like [[Music of Japan|musicians]] or [[Japanese painting|painters]]. The title of {{tlit|ja|tōji}} was historically passed from father to son. Today new {{tlit|ja|tōji}} are either veteran brewery workers or are trained at universities. While modern breweries with cooling tanks operate year-round, most old-fashioned sake breweries are seasonal, operating only in the cool winter months. During the summer and fall, most {{tlit|ja|tōji}} work elsewhere, commonly on farms, only periodically returning to the brewery to supervise storage conditions or bottling operations.<ref>{{cite web|url=http://www.esake.com/Knowledge/Ingredients/People/people.html|title=The People|publisher=eSake}}</ref>