Among the many hot beverages the world enjoys, tea is probably the number one. No matter how many people drink coffee, no beverage has a history like tea. From the tea ceremony cultures of the East to the Boston Tea Party of the West, the history of tea is long and full of stories. As everyone knows, tea is a drink made by boiling down the leaves of a plant. There are many types of tea: black, oolong, green, yellow and white being the most common. Teas made from more aromatic plants such as jasmine and chamomile are typically put in a separate category known as herbal teas. One surprising fact about tea is that most of them are derived from the same plant.
The plant Camellia sinensis is the source of all teas, with the aforementioned black, oolong, green, yellow and white teas all coming from the leaves of this one plant. However, what makes each tea unique is the way the leaves are processed. For example, if you steam freshly picked leaves of the Camellia sinensis plant then dry them out, you make green tea. If you wither the leaves then lightly crush and bruise them to promote oxidisation, you make black tea. The different ways of processing tea leaves gives each type of tea a unique flavour due to a variety in the ratio of various chemicals. For example, black tea is rich in tannin because of oxidisation, whereas green and oolong teas are milder as they have higher levels of catechins than tannin (the oxidised product of catechin). As catechins act as antioxidants in the human body, green tea is effective in slowing the aging process.
Although the source of the leaves are the same, the different ways of processing makes each tea unique in their ways of preparation. The milder white, yellow and green teas are best prepared by steeping them in water heated to (or cooled from boiling) 70~80°C for 1~2 minutes, while oolong and black tea should be steeped for 2~3 minutes in near-boiling water (80~99°C) for the best taste.