Black tea is the result of fully oxidized tea leaves, yielding a darker amber color. Due to full oxidation, black tea will contain the highest trace of caffeine among other tea varieties. In China, black tea is known as "Hong Cha" or red tea. In America, red tea is more commonly known as rooibos, a South African herbal. Black tea ranges from floral to earthier and smokier flavors. Note that black tea due to it's processing, can be retained for longer shelf life.