Although initially raw tea leaves were simply chewed to release the flavours, the practice of boiling tea leaves in water had become established by the 1st century BC. In the days of China’s Tang Dynasty (A.D. 618–907), freshly plucked tea leaves were steamed, pounded with a pestle and mortar, compressed into cakes, and dried. To prepare the tea for drinking, the cake was broken into pieces, ground to a powder, sifted, and boiled in water in a cauldron. During the Song Dynasty (A.D. 960–1279), tea producers continued to compress the leaves into cakes, but they also manufactured loose-leaf teas. Both were ground to a powder and placed in a tea bowl into which water was added and the mixture whipped with a bamboo brush to create a frothy drink.