acescence
/əˈsɛsns/noun
The action of becoming acid or sour; a tendency to become acid or sour; the process of acetous fermentation. Also: acidity, sourness. In later use chiefly with reference to the volatile acidity of wine.
Origin
Mid 18th century; earliest use found in Robert Dossie (d. 1777). From acescent, perhaps after French acescence.