The pH value of lightly roasted breakfast coffee is between 4.5 and 4.7, the pH value of medium-dark roasted FullCity is around 5-5.5, and the pH value of dark roasted coffee (DarkRoast) is above 5.5. For ordinary people's taste buds, if the pH value of a drink exceeds 5.5, it is difficult to detect its sour taste. The pH value of heavily roasted beans often exceeds 5.5, so it is difficult to taste sourness in the drink. Human taste buds easily taste sour to drinks with a pH value below 5, so light roasted beans will have a sour taste.

Ranges from 0 to 14, with solutions from 0 to 7 considered acidic, while solutions from 7 to 14 considered alkaline. Most coffee varieties are acidic, with an average pH between 4.85 and 5.10.

Extended information:

Coffee mainly presents two flavors, one is bitter and the other is sour. Whether coffee is sour or not depends on the degree of roasting of the beans. The longer the roasting time, the higher the degree of caramelization, and the more acidic substances are destroyed, the less likely to be sour. The shorter the roasting time, the lower the degree of caramelization and the less acidic substances. There is less damage and it is easy to brew sour coffee, which means that roasting degree and sourness are inversely proportional. The darker the roasted coffee, the less sour, and the lighter the roasted beans, the more sour.

In addition, the temperature of brewing coffee also has an impact. Water with a slightly lower temperature is definitely easier to brew sour coffee than a slightly higher water temperature. People who are afraid of acidity should drink the coffee while it is hot, otherwise the sour taste of the coffee will be Occurs as the temperature decreases.

Baidu Encyclopedia-Coffee