How are teas categorized?
Green tea, white tea, Oolong and black tea, they all sound familiar. How many different tea varieties are actually out there? And how are they grouped?
All conventional teas are made of Camellia sinensis leaves. It is not certain as how many actual varieties are out there, from hundreds by conservative estimate to thousands by other claims.
Based on the level of fermentation/oxidization during their process, teas are however categorized into following six categories.
Green Tea
Green teas are unfermented/unoxidized teas. The tea leaves are typically harvested during the spring and dried immediately, pan dried or steam dried. Green teas are consumed fresh. The new season teas are the best.
Green teas are extremely refreshing.
Yellow tea
Yellow teas are unfermented/unoxidized, similar to green teas. The difference is that the yellow teas are deliberately piled to make the tea leaves turn light yellow during their processing, a technique called ‘Ou-Huang’ (渥黄). Yellow teas have yellow tone in both dry leaves and the tea brew.
Yellow teas are aromatic and refreshing.
White tea
White teas are lightly oxidized, but least processed. The processed white teas largely retain the natural characteristics of the fresh tea leaves. White teas’ processing is relatively simple but highly skillful - withered and then dried. There is no rubbing, pressing, baking or roasting involved.
White tea’s flour is subtle, some describe it as light honey sweet. White teas can be consumed both fresh or aged.
Oolong tea
Oolong teas are semi-oxidized, sitting between unoxidized green teas and fully oxidized black teas. There are many teas in this category with various degrees of oxidization.
Most of Oolong teas have certain level floral fragrance, produced through roasting the tea leave, but not blending with additives.
Black tea
Black teas are classified as fully oxidised teas. The colour of the tea brew is deep red and their flavours are often sweet with a hint of other natural elements, such as flora, pine and date. The flavours of premium black teas are produced though processing the tea leaves, but not adding addtives.
Hei Cha/compressed tea
This is a class of teas that are mostly compressed and all are aged. There are a few sub-classes in this family, most well-known ones are: Pu-erh tea, Fu Bricks, Liu Bao, Tian Jian and Qian Liang Cha.
This is a family of teas that ferment – with micro-organisms involved. The fermentation occurs during and after the production of the products. Their quality typically improves while aging.
Note:
Teas originated from China. Fermentation is the traditional term used in China for a long time to classify the different tea categories, for example green teas are unfermented and black teas are fully fermented. Scientifically, there are two types of bio-chemical activities occur during the tea processing:
1. Oxidisation. Chemical changes of the bio-chemical compounds without microorganisms involved. This occurs during the processing of the white tea, oolong tea and black tea.
2. Fermentation. Bio-organisms are actively involved in the chemical changes during and after the processing. This occurs to Pu-erh tea and Hei Cha.
In many tea books from China, Oolong tea for example is classified as semi-fermented. This should be treated as a term culture and tradition, but not a scientific term.
