Phenolphthalein indicator
フェノールフタレイン指示薬ふぇのーるふたれいんしじやくPhenolphthalein indicator is a chemical indicator used to assess whether an environment is acidic, neutral, or alkaline. It is used in measuring the amino acid level and in evaluating pH. In particular, when the pH is in the range of 8.2 to 10, it changes from colorless to pale pink. This property makes scientific analysis of sake quality control and flavor possible.