Snow accumulated during the winter begins to thaw and seeps into the ground, thereby being filtered. This ground water then wells up as rivers everywhere in Niigata Prefecture. Since 80% of sake is made of water, it is no exaggeration to say that water plays the most essential role in deciding the future taste of sake. In fact, each brewery has its own water source in the form of a well or spring water. Accordingly to this, the quality of water is put under a stricter control than tap water. Since water is used not only to prepare but also to wash and soak the rice and to wash tools during the whole process of brewing, both the quality and quantity of water matter. It is said that about 40 times of water is used in the whole process of brewing as that used in the preparation stage.
In Niigata Prefecture, there are many sites famous for their water such as Ryugakubo (Tsunan Town), Morimori no Mori spring (Nagaoka City), which were chosen among the 100 famed mineral waters by the former Ministry of Environment, and Kitshou Shimizu (Murakami City), Odeguchi Sensui (Joetsu City), Uho-no Shimizu (Myoko City), Arakawa (Sekikawa Village), which were selected as some of the 100 famed mineral waters of Heisei. Many breweries use these waters in their sake making. For example, Morohashi Brewery in Nagaoka uses Morimori-no-Mori Wakimizu and in the same city, Kusumi Brewery uses Sakaya-no Shimizu, a famous water in the prefecture; the latter is famous for ‘Kame-no O’ where the comic ‘Natsuko no Sake’ was set in. Hakkai Brewery in Minami Uonuma City uses Raidan Sama no Mizu, known as water for longevity and sweetness. In total, there are sixty-two famed waters in Niigata Prefecture, four of which were added recently in Heisei year 26 (2014).
Since old times, it has been said that ‘The sake of Nada (Hyogo) is manly and that of Fushimi (Kyoto) is feminine.’ This phrase means that since water in Nada is rich in minerals, a crispy, dry sake is produced there. Whereas the water in Fushimi has less minerals, the sake produced from that water becomes milder. But the water in Niigata, much milder than that of Fushimi, is called super soft water. This is because of the ample precipitation from heavy snow and a short staying time of river and underground water in the strata. Soft water contains less minerals such as calcium and magnesium. Minerals encourage yeast fungi to ferment, so in hard water, fermentation proceeds faster, while in soft water it is slow. It had been said that the super soft water of Niigata was never suitable for brewing because yeast fungi did not progress desirably. We owe a lot to the development of the unique rice of Niigata – Gohyaku Mangoku Mai that made it possible for soft water, through prolonged fermentation at a low temperature, to produce sake with a clear taste.