Regular Tea (also known as Black Tea):
Black tea is one of the most common teas available and is mostly grown in southern Asia and Africa. With black tea the leaves of the tea plant are allowed to completely ferment, and drying of the leaves is done at the same time. Black tea has a strong flavor and contains more caffeine than the teas that are less fermented. Black tea is often sold in blends;for example Earl Grey, which is a blend of black tea and bergamot oil.
With green tea, the leaves of the tea plant go through only a minimal amount of fermentation either with steam, which is a traditional Japanese method, or by drying in hot pans which is a Chinese method. Gunpowder tea is a type of green tea in which each tea leaf has been rolled into a small pellet, but this is usually done only with tea leaves of very high quality.
The difference is simply explained below:
The difference between Green and Black Tea occurs during the processing of the tealeaves. Both types are normally hand plucked and then withered. Tealeaves are laid out and allowed to wilt for several hours. Withering reduces the moisture content in the leaves and prepares them for the next step, which is rolling. The rolling process is critical because it prepares the leaves for oxidation (fermentation) by rupturing the leaves and exposing enzymes to oxygen. Black tea gets its color and character as a result of the fermentation process. The term "ferment" has been used by the tea industry for years, but the process is more correctly defined as oxidation. The enzymes in the tealeaves are allowed to oxidize after rolling. Green tea, however, is not oxidized; the leaves are steamed or baked immediately after being plucked. They are then rolled and dried allowing the leaves to remain green in color. Both teas are then dried and sorted.