What water should be used?

Sake is made of at least 80% water. It is the main ingredient and undeniably influences the taste. In the final stages of the sake-making process, water is even added to adjust the taste. Water is also used to clean, soak and steam the rice, and to clean utensils and equipment. The taste of the water leaves its mark.

La teneur en minéraux est déterminante du goût du saké. Le fer et le manganèse induisent des odeurs et des saveurs désagréables tandis que le potassium, le magnésium et certains composés de phosphore nourriront le KojiQu’est ce que le Koji ? Dans le cadre du saké, le koji est une moisissure noble qui permet de transformer l’amidon contenu dans le riz en sucre. On appelle cette étape la saccharification.* et les levures qui s’activeront et se propageront d’autant mieux pour envahir plus vite le brassin diminuant les possibilités qu’il soit contaminé par d’autres organismes nuisibles.

Pure spring water is therefore required. It is said that hard waterune eau est considérée comme dure si son PPM  est supérieur à 120PPM is better for making good sake than soft waterune eau est considérée comme douce si son  PPM est inférieur à 60PPM de. Hard water will make a drier sake, while soft water will make a sweeter sake.

Beware!
Some breweries use mains tap water which they will filter and re-mineralise. it is also always possible to rebalance the minerals in your water, even spring water, to have an ideal water.
I don't think it's a problem, but if you do it, it's good to say so. Too many breweries communicate about their water or their traditions, making lies by omission.

The hardness of water varies from source to source. It is determined by the concentration of certain minerals, especially magnesium, calcium and calcium carbonate. It is measured in parts per million (ppm). At less than 60 ppm, the water will be considered very soft; in Japanese it is called nansui 軟水On the other hand, if it contains more than 120 ppm, it is called hard; it is called kôsui 硬水

soft water = 0 to 60ppm
medium hard waterune eau est considérée comme moyennement dure si son PPM  est compris entre 60PPM et 120PPM = 60 to 120ppm
hard water = from 120ppm

evian = 345ppm

Koji* = microscopic fungus that enables enzymatic fermentation by transforming rice starch into sugar