Oolong tea is gently rolled after picking, allowing its essential oils to slowly oxidize. This reaction to the air darkens the leaf and produces distinctive fragrances. Once the leaf has developed properly, the tea maker must stop the oxidation by heating it rapidly in a process called 'panning.' The leaf is then rolled into its final shape. Producing this handcrafted tea properly is extremely labor intensive. The tea maker must carefully balance many elements in the critical first few hours, including weather conditions, leaf quality, and oxidation time. Depending on the processing method, the resulting tea can be anywhere from a green to a black. The finest oolongs are often prepared and enjoyed Gong Fu style (in a small clay pot for multiple infusions) to savor their complex flavor and aromas.