Darjeeling tea is famous for it’s distinctive and unique taste. It is also known to promote mental alertness and improve brain function. Darjeeling tea is of the black variety, so it contains no caffeine. This type of tea often has a musky sweetness or a slightly astringent flavor that distinguishes it from other types of teas. You can either buy darjeeling tea that comes in loose leaf form or you can purchase bags of the tea from speciality stores.