Black tea is the result of picking, withering, rolling, fermentation, drying and other steps produced; fermentation process one more than green tea. Fermentation refers to tea in the air oxidation, fermentation makes the tea polyphenols and tannins decrease, resulting in a theaflavin thearubigins other new ingredients and alcohols, aldehydes, ketones, esters, etc. aromatic substances. Therefore, black tea, black tea, or black mingled with buds in orange; tea showed a deep red; fragrant; due to less bitter taste, so taste more sweet, mellow.
Black tea and green tea different, with time lose the taste of green tea, black tea can be stored for a long time and the taste of the same, so will be able to adapt to the long-distance transport. This is perhaps one of the key reasons for tea spread to the West.