After Tea Leaves Are Picked - The Making of Artisan Oolong Tea
On the day of harvest, as the new growth of leaves that reach maturity within a two-month growing season are picked, they are carted from the farm to the factory. The first step of processing the leaves is solar withering. The leaves are spread by hand on tarps outdoors and undergo primary withering for about half an hour, depending on the weather.
The leaves are then gathered on their tarps and brought indoors for a longer, slower wilting process - allowing for partial oxidation of the leaves to occur. Before they are put on bamboo trays for several hours of slow wilting and oxidation, the leaves are "shuffled" to increase circulation and redistribute moisture for even oxidaton.
Depending on the teamaker and the conditions that the leaves are harvested and processed in, the steps can vary, but they are all intended for the same goal - partially oxidizing (perhaps the most idiosyncratic and subtly significant factor in the processing), rolling, and drying of the tea leaves. The indoor withering/oxidation phase is interspersed with shuffling and tumbling of the leaves to "wake them up" and in effect revitalize the circulation within the leaf to promote even distribution of moisture in order to maximize uniform oxidation throughout the leaf.
When the oxidation process is determined to be ripe, the leaves are then exposed to high heat in tumble dryer/heaters that kill the naturally occurring live enzyme in the leaf that is responsible for the primary oxidation of the leaf.
After the leaves have passed the "sha qing" or "kill green" step, depending on the extent of drying in the "sha qing" stage of processing, the leaves are either loosely rolled and sent through a hot air conveyer belt machine for further drying, or they are gathered on tarps to reabsorb the atmospheric moisture in preparation of the rolling and drying phase the next day.
The next morning, typically within 5 hours of completing the "kill green" and drying stage, the leaves begin their labor intensive process of being rolled and dried, intermittently, for several hours. This brings us to more than 24 hours of processing since the leaves were picked. At this point, the leaves are essentially cured and ready to be sold to merchants who will proceed to roast the tea to their preference, or at least have the leaves "roasted dry" to remove any remaining moisture content that could affect the freshness and shelf life of the tea leaves.