There are three different types of teas produced- Black Tea, Green Tea and Oolong Tea.
Green tea is made by withering tea leaves - and then steaming, rolling and drying them. It undergoes minimal processing, and contains 80-90% catechins and flavones (10% of total flavonoids). The infused leaf is green, and the liquor is mild, pale green or lemon-yellow.
Black tea involves additional processing (i.e. aeration and withering). As a result, it has different levels of catechin (20-30%) and flavonoid content (theaflavins and thearubigins represent 10% and 50-60% of total flavonoids respectively).
Oolong tea is a partially or semi-fermented tea. A full-bodied tea with a fragrant flavour and sweet fruity aroma, it has some qualities of both black tea and green tea due to its manufacturing process. It is more suitable for people who prefer a low caffeine option.
White tea is appreciated by tea connoisseurs for its unmatched subtlety, complexity and natural sweetness. It is also considered to be a far greater source of antioxidants than green tea because the tea leaves undergo minimum processing.