The taste and properties of a tea are highly affected by a process known as oxidation. Oxidation takes place when picked tea leaves are left to react with oxygen.
During the oxidation period, a wide range of processes will occur within the leaf and this will for instance affect the amount of caffeine, antioxidants and tannins in the tea.
Tannins are a special type of polyphenols and these compounds are responsible for the characteristic bitter taste found in tea.
Depending on which method you use when you prepare the tea leaves, you will get one of four basic tea types: Green tea, Black tea/Red tea, White tea or Oolong tea.
There exists other ways of preparing tea, but such methods are not as widespread and frequently utilized as the four main methods.
Examples of teas created using special preparation methods are Pu-erh tea, Yellow tea and Kukicha tea.
Black tea is a tea where the oxidation process has been allowed to proceed for a long time. Black tea is therefore much more oxidized than the other three main tea types; Green tea, White tea and Oolong tea.
Black tea has the highest caffeine content of the four main tea types, and a lower amount of antioxidants. This does not mean that black tea is without any antioxidants; it just has a lower antioxidant level than the other tea types.
Generally speaking, black tea has a stronger flavour and this flavour can be preserved for many years during the right conditions. Unlike black tea, green tea will often loose its flavour within a year.
So, why do I refer to black tea as black/red tea in the beginning of this article? The truth is that traditionally, the term red tea is a more accurate name for this type of tea than black tea. Red tea is the Chinese name for heavily oxidised tea, and similar names are used in Japanese and Korean too.
The name is probably derived from the colour of the drink that is the result of black tea. Today, most English speaking people do however use the term “black tea” to describe heavily oxidised tea from the camellia sinensis plant and the term “red tea” is instead used for the so called Rooibos tea.
Rooibos tea is made from a South African plant named Aspalathus linearis and this plant is not at all closely related to the East Asian tea plant.