The relationship between ingestion of coffee and reduction of mental stress was investigated in 256 young Japanese women. Among the 68% of subjects whose questionnaire responses indicated that they liked coffee, 68% indicated they feel relaxed when they drink coffee. In an organoleptic test, coffee extracted at 80 degrees C exhibited a greater relaxation effect than coffee extracted at 65 or 95 degrees C. This effect showed a significant negative relationship to sourness, suggesting that the relative lack of sourness enhances feelings of relaxation. Coffee drinking also decreased experimentally-induced mental stress evaluated by chromogranin A concentrations.
