Oolong Tea is gently rolled after picking allowing the essential oils to react with the air and slowly oxidize. This process turns the leaf darker with time and produces distinctive fragrances. When the leaf has reached the desired oxidation the leaf is heated, in a process called "panning," to stop the process. It is then rolled to form the tea into its final shape. The resulting tea can be anywhere between a green and a black, depending on the processing method. This tea is handcrafted, undergoing a labor-intensive process. The tea-maker must carefully balance many elements in the critical few hours after the leaf is picked including weather conditions, quality of the leaf, and the time the leaf oxidizes. The finest oolongs are often prepared and enjoyed Gongfu style to savor their complex tastes and fragrances.