Dark oolongs have the so-called longitudinal leaf twist. Simply put, the leaf looks whole, elongated and heavily wrinkled. The most popular dark oolongs are Da Hong Pao, Feng Huang Dan Cong, Shui Xian, Zhou Gui, Tie Luo Han.

The main group of dark oolongs is produced in Wuyishan. Hong Pei technology is used for processing. In special rooms, the tea is slowly roasted in baskets on charcoal covered with a slab. The tea undergoes this procedure many times during the aging period. It is believed that in order to stabilize the taste, it is necessary to age the tea for at least a year and subject it to Hong Pei about 5 times.