Webster 1913 Edition
The quality or state of being sour.
Webster 1828 Edition
1.Acidity; sharpness to the taste; tartness; as the sourness of vinegar or of fruit. Sourness being one of those simple ideas which one cannot describe.
2.Asperity; harshness of temper. Take care that no sourness and moroseness mingle with our seriousness of mind.