So...What is Tea?
Tea is interpretated quite differently across cultures. Besides the English term "tea", it also appears in multiple characters and pronouciations such as "cha","chai","ceai""tsa","te". In certain culutres, tea refers to everything related to plant infused beverage, while in other cases, tea refers to drinking beverage made exclusively from the plant Camelia Sinensis, which has over hundreds of sub varieties. In Chinese tea culture, 90 percent of the time tea is associated with the crafted products of Camelia Sinensis, while certain regional customs relate tea to herbal/floral drinks as well.
It is the general consensus that tea originates from current day southwestern China and the norther Myanmar region. The two predominate varieties of Camelia Sinensis are Camelia sinensis assamica and Camelia sinensis sinensis, most of the tea today comes from these two sub-varieties and their hybrids. Tea is very specific to its environment and growing conditions, similar to wine. This phenomenon is referred to as the "terroir". It means each place with its unique set of geographic location, nautral condition, microclimate, cultural background, customed crafting techniques, all contribute to the taste and flavour of the tea that is crafted there. This is also why true tea usually present different taste and flavour across seasons because of the various inputs. Bsed on this knowledge, different tea cultivars in different regions are crafted accordingly using specific techniques and methods to generate the most balance and appropriate flavour profile.This is also what gives rise to the diverse types of tea that is availabe today. For example, the tea plants in Yunnan are more conventionally used to produce puer tea while tea plants from the Hangzhou region are used to produce green tea. The two tea varieties are fundamentaly different in terms of their biological compositions and components, therefore the flavours that they present are very different. If you use broad leaf variety from Yunnan to produce fresh green tea it might not be as tasty as the ones from Hangzhou. As climate and nautral conditions changes, tea crafting techniques and knowledge is constantly being tested and experimented to produce quality products.
Within the Chinese tea system, tea is catagorized into 6 main types based on their respective level of oxidization and creafting techniques. White, Yellow, Green, Oolong (semi-oxidized), Black and Dark tea. The level of oxidation, also refered to as "fermentation" most of the time, refers to the process in which tea leaves react with air. When leaves are bruised, it realize a certain liquid/juice thay will react with the air and subsequently darken the colour of the tea leaf (similar to an apple cut in half). Through mechanisms like heating, roasting, physical handlings, the biological components of the tea leaves get transformed to different degrees, and as a result affects the aroma, taste, flavour, aftertaste and the appearance of tea.