Oxidation (also known as fermentation) is the natural process that alters the chemical structure of the leaf, allowing key flavor characteristics to emerge. Our rolling process releases the enzymes naturally occurring in the tea leaves. These enzymes, which have been released by the rolling, react with the air.Temperature, humidity, and time are the factors that must be controlled during this process. As blenders, varying the length of time is one way to change the character of the tea. The longer the leaf oxidizes the softer its taste, the deeper its color and the higher its caffeine.