Herbal tea Herbal tea Herbal teas — less commonly called tisanes (UK and US , US also ) — are beverages made from the infusion or decoction of herbs, spices, or other plant material in hot water. They do not usually contain caffeine. Herbal teas should not be confused with true teas (e.g., black, green, white, yellow, oolong), which are prepared from the cured leaves of the tea plant, "Camellia sinensis"), nor with decaffeinated tea, in which the caffeine has been removed. Like beverages made from true teas, herbal teas can be served hot or cold. Some feel that the term "tisane"
Camellia sinensis The leaves are long and broad. Fresh leaves contain about 4% caffeine, as well as related compounds including theobromine. The young, light green leaves are preferably harvested for tea production; they have short white hairs on the underside. Older leaves are deeper green. Different leaf ages produce differing tea qualities, since their chemical compositions are different. Usually, the tip (bud) and the first two to three leaves are harvested for processing. This hand picking is repeated every one to two weeks. In 2017 Chinese scientists sequenced the genome of "Camellia sinensis var. assamica ." It contains about three billion base