Hydrogen ion concentration (pH)

Hydrogen ion concentration (pH) is an indicator of how acidic or alkaline a solution is. pH is expressed as a number from 0 to 14, with 7 being neutral. Values below 7 indicate acidity, and values above 7 indicate alkalinity. In sake, the typical pH range is about 4.2 to 4.7, and it is an important factor affecting the flavor and shelf stability of the sake. The lower the pH of a sake, the stronger its sourness, and it may come across as fresh with a clean finish. On the other hand, a higher pH is characterized by a mellow, sweeter taste. Appropriate pH control during the brewing process also contributes to better quality.