I am doing my IB Chemistry HL IA on coffee oxidation, and how varying levels of oxidation (or after an amount of time) affects its pH value. I know that over time it will get more acidic, in which the pH value will drop, but I want to know what exactly in coffee causes the oxidation to happen?
I am aware that after brewing the shelf life of the coffee beverages immediately starts to decrease, where the longevity depends on the storage methods of the beans themselves, so what compound reacts with oxygen and loses hydrogens (or electrons)?