White tea is the most minimally processed tea variety, making it also the tea that holds the lowest caffeine content. White tea, considered rare and fine, was developed in the early Imperial Dynasty (between 600 and 1300) as a custom to pay tribute to the Emperors. White tea can only be plucked for two weeks a year, making it more difficult to produce, and therefore, more desirable. In modern days, white tea is still considered the most rare and delicate variety, comparable to the "Grand Cru" of teas.