INFLUENCE OF pH ON FLAVOUR STALING DURING BEER STORAGE

A decreasing pH accelerated an increase in the chemiluminescence production and degradation of isohumulones and procyanidins during the storage of beer and using a model system. The sensory test showed that the addition of HCI to fresh beer accelerated the flavour staling during beer storage but that the addition of HCI to stored beer did not significantly accelerate the flavour staling. Therefore, it was thought that the acceleration of beer flavour staling is not dependent on a decrease in pH such that the decreasing pH isolates stale flavour aldehydes by a dissociation from staling-flavour aldehyde adducts but based on the fact that the decreasing pH accelerates the flavour staling reactions, free radical reactions, during beer storage.