Here is Part 1 on the basic processing for Taiwanese Oolongs. I hope this can help you to understand how an Oolong is made and bring you to deepen your appreciation for these amazing teas.
-Tea Picking: For Taiwanese Oolongs, the standard picking is two leaves and a bud. For a traditional style Oolong, producers want the leaves to be mature enough. Leaf maturity is judged by the ratio of the two open leaves. According to the Tea Reform Institute, the perfect set for picking is for the first open leaf to be 70% the size of the second open leaf. Traditionally, the best tea picking time is around 10am because the dew has just evaporated from the tea leaves. Nowadays, not many farmers follow this practice anymore. Tea pickers are now paid by the weight of the leaves they pick (and sometimes they are paid on a per-day basis) so they want to start as early as possible. In a lot of farms, you will see someone with a broom hitting the tea bushes gently before the picking starts to get rid of the remaining dew on the leaves.
-Outdoor Withering: After enough fresh picked leaves are collected, farmers will lay the leaves out on big pieces of canvas outdoors. The duration for this process varies depending on the weather, but is usually around 30 minutes. I heard from a farmer that the perfect condition for this process is sunshine filtering through clouds. I always thought a bright and sunny day would be more perfect, but he said bright sun can "burn" the leaves. The purpose of this process is to let some of the water evaporate from the leaves (走水, "water walking") so that some of the bad smell (臭青, "stinking green") will evaporate, too. Due to the loss of some water, the cell membrane weakens and oxidation kicks in. One can smell some sort of light floral fragrance during this process. I asked some farmers how they know when this process is done and they all said it's done when a light floral note shows up, and they also know it by the look of the leaves. The first open leaf loses its shininess on the surface and the leaves feel soft.
In my next post, we'll talk about the next two steps of the process. Look for it soon!