The simplest way to understand how oxidation works is to compare it to taking a first bite out of an apple. Than imagine your best friend called you and wanted to tell you all about how his/her date went last night. Twenty minutes later you hang up the phone and before you realize, something has happened to your apple. What is the color of it now as compared to before? With tea, oxidation refers to how and when the oxidation occurs, and how and when the oxidation stops.
The process of white tea is quite minimal which includes drying and withering almost immediately after picking. Some refer to white tea as a “raw” tea. The secrets of the teas withering process varies from region to region in Fujian China and depends on climate conditions and family traditions. White tea gets its name from a silvery type down that cover the leaves and buds, known as “Hao.”
Green tea leaves are plucked then immediately cooked to prevent oxidization. Japanese greens are generally steamed resulting in a bright green infusion while Chinese greens are pan, or wok roasted to neutralize the natural enzymes, rolled, then dried which results in a pale green color.
Full leave Black Tea leaves are produced through a rolling and cooking action resulting in 100% oxidization process. As a result, black tea generally provides a robust and brisk flavor and as the juices are brought to the surface from the rolling action the effect contains more caffeine than the teas in other categories.
Finally, Oolong Teas are hand tossed in baskets to bruise the leaves and release essential oils that initiate the oxidation process then withered between 2-8 hours depending on moisture, climate, and results the artisan is looking to achieve. Oolong teas being partially oxidized can be categorized generally in between a Green Tea and Black Tea in terms of length of oxidation, strength of flavor and caffeine content. Oolongs can be between 1% oxidized which would be closer to a green tea up to 99% oxidized closer to a black tea.