What is "traditional sake brewing"? "Commemorating the registration of UNESCO Intangible Cultural Heritage" Series Part 3
The master brewers and sake brewers have honed their sake brewing skills with years of wisdom and experience, and have built a world-class culture. What is the traditional brewing process?

The defining feature of "traditional sake brewing" is that it skillfully harnesses the power of a small microorganism called koji mold. Using the wisdom and experience accumulated over many years, the master brewers and brewers have continued to carefully hone their skills, building a sake brewing culture that is now the pride of the world. So what exactly are the steps involved in making sake using traditional brewing?
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Traditional sake brewing, its techniques and processes
The first step is to prepare the ingredients for sake brewing."Raw material processing"The outer layer of the rice is carefully scraped off, washed, soaked in water, and steamed to finish. The steaming process creates favorable conditions for the growth of koji mold, which plays an important role in supporting the subsequent processes.
The next step, "making koji," is to sprinkle koji mold on the steamed rice in a special room called a "koji room," mix it together, and then cultivate it under controlled temperature and humidity. Koji is responsible for converting rice starch into sugar, and is a crucial step in sake brewing.
Next is "Making the yeast starter" Sake yeast is cultivated in a mixture of steamed rice, koji, and water. Once the yeast starter is obtained in this process, alcoholic fermentation begins.
Next is finally"Fermentation of moromi"Moromi refers to the state before it becomes sake, and is made by adding steamed rice, koji, and water to the yeast starter. During this fermentation process, the "multiple parallel fermentation" that is unique to sake takes place.
In multiple parallel fermentation, two processes take place simultaneously: the koji converts the starch in the steamed rice into sugar, and the yeast converts that sugar into alcohol.The process is characterized by the fact that it produces a high-alcohol drink because the alcoholic fermentation proceeds while sugar is gradually added. This process is a key point in sake brewing that is not found in wine or beer brewing.
In addition, in this process,"Three-stage preparation"A technique called "adding the ingredients in three batches" is used, which keeps the mash in a healthy state and allows ideal fermentation to proceed.
After fermentation, the mash is pressed and separated into raw sake and sake lees. The freshly pressed sake is left to sit and the cloudiness is allowed to settle, after which it is carefully filtered. It is then pasteurized (heat sterilized) and stored, resulting in a mellow sake with a well-blended aroma and flavor.
The power of koji that supports sake brewing
One thing to pay special attention to when brewing sake is the presence of koji. If we look at brewed alcoholic beverages other than sake, each has its own unique brewing method. For example, beer is made using a method called "simple fermentation," in which the starch in malt is converted into sugar and then yeast is added, while wine is made using a "simple fermentation" method, in which the natural sugar in grapes is converted into alcohol by yeast.
In contrast, sake is made using a process called "multiple parallel fermentation," in which starch is converted to sugar by koji mold and alcoholic fermentation by yeast proceeds simultaneously. This unique sake-making method is made possible by Japan's unique koji.
Koji mold is deeply rooted in our diet. Yellow Koji mold, which has long lived in nature in Japan, is used to make sake and mirin, as well as various fermented foods that are found on our dinner tables every day, such as miso, soy sauce, rice vinegar, and pickles. In addition to yellow Koji mold, black Koji mold and white Koji mold also play important roles in supporting the production of awamori and shochu, respectively.
Looking overseas, brewing using koji is also practiced in East Asian and Southeast Asian countries, but the types of fungi used and the methods of making koji are very different from those in Japan. The reason why Japan has developed such a unique koji culture is because of the climate, geography and natural environment that are suitable for the growth of koji mold. Japanese koji, which was cultivated in this favorable environment, continues to support traditional sake brewing to this day.
Brewers opening up new possibilities for sake
While the brewers who carry out traditional sake brewing continue to cherish the reliable techniques that have been handed down from generation to generation, they are also beginning to proactively embrace new ventures and innovations, exploring new possibilities for sake.
In the brewing process, they are trying out new yeasts and cultivating their own yeasts to expand the variety of flavors and aromas. They are also experimenting with creating sparkling sake through secondary fermentation in the bottle* and fermenting with white koji mold and wine yeast, which are used in shochu brewing, to create sake with unprecedented qualities.
*Secondary fermentation in the bottle: After the mash is roughly pressed, it is bottled without pasteurization, and fermentation continues in the bottle, producing natural carbon dioxide.
Furthermore, in order to make sake accessible to people who were previously unfamiliar with it, an increasing number of breweries are trying new approaches to sake brewing, such as lowering the alcohol content or pursuing a light flavor that can be enjoyed casually in a wine glass. Each brewery is approaching sake brewing with a free-spirited approach, wanting to propose diverse ways of enjoying sake without being bound by traditional drinking methods.
What's interesting is that while some breweries are introducing the latest technology, such as temperature control via smartphone, there is also a growing movement to return to traditional methods and tools, such as making koji by hand, reviving the old-fashioned way of making yeast starter, and using wooden barrels and barrels.
In this way, brewers are trying to pioneer a new era of sake brewing while skillfully maintaining a balance between tradition and innovation. It is a journey in which ancient wisdom will be passed on to the future, and Japan's world-renowned sake culture will continue to weave new stories as it aims for new horizons.
Reference: National Tax Agency"Japanese traditional sake brewing using koji mold" research report
"Commemorating the Registration of UNESCO Intangible Cultural Heritage" Series 2:Japan's sake brewing culture nurtured by the local climate
"Commemorating the Registration of UNESCO Intangible Cultural Heritage" Series Part 1:Passing on Japanese sake brewing to the future!
Text by Yoko Ishikawa
Freelance writer / Japanese Sake Adviser (SSI) / WSET Level 1 / Born in Tokyo / Living in Las Vegas, USA.
After discovering delicious sake here, he opened his eyes to Japanese sake. Recently, he not only enjoys drinking sake, but also brewing it at home.
Social Media: Instagram @lvsakegirl note @lvsakegirl
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