Dianhong tea making technique is a national intangible cultural heritage. Dianhong tea, also known as Yunnan black tea, is abbreviated as Dianhong. Everyone is used to calling it Yunnan Dianhong tea. Dianhong tea is mainly produced in the western and southern parts of Yunnan. The black tea produced in Yunnan has a unique feature of "colorful and fragrant, high and pure fragrance". The finished black tea is plump, full and tight in appearance, and the bottom of the leaves is ruddy, which is the best among black teas. Dianhong tea processing technology 1. Withering Withering refers to the process in which fresh leaves lose water after a period of time, so that certain hard and crisp stems and leaves become wilted and withered. It is the first process in the initial processing of Dianhong tea. After withering, water can be evaporated appropriately, the leaves are soft, the toughness is enhanced, and it is easy to shape. In addition, this process and the disappearance of the grassy taste and the appearance of the tea fragrance are important processing stages for the formation of the aroma of Dianhong tea. 2. Rolling The purpose of rolling Dianhong tea is the same as that of green tea. The tea leaves are shaped and the color, aroma and concentration are increased during the rolling process. At the same time, because the leaf cells are destroyed, it is convenient to carry out necessary oxidation under the action of enzymes, which is conducive to the smooth fermentation. 3. Fermentation Fermentation is a unique stage in the production of Dianhong tea. After fermentation, the color of the leaves changes from green to red, forming the quality characteristics of red leaves and red soup of Dianhong tea. The mechanism is that under the action of rolling, the permeability of the tissue cell membrane increases, the polyphenols are fully in contact with the oxidase, and oxidative polymerization occurs under the action of the enzyme, forming the color, aroma and taste quality of black tea. If the fermentation is moderate, the young leaves will be red and uniform, the old leaves will be red with a hint of green, the grass smell will disappear, and there will be a ripe fruit aroma. 4. Drying Drying is the process of baking the fermented tea leaves at high temperature to quickly evaporate the water and achieve the dryness to maintain quality. There are three purposes: using high temperature to quickly inactivate enzyme activity and stop fermentation; evaporating water, reducing the volume, fixing the shape, and maintaining the dryness to prevent mildew; emitting most of the low-boiling point grass smell, intensifying and retaining the high-boiling point aromatic substances, and obtaining the unique sweet fragrance of Dianhong tea. Dianhong is made from fresh leaves of Yunnan large-leaf tea trees, which are first withered, rolled or cut, fermented, and baked to make finished tea; then processed into Dianhong Gongfu tea, and then rolled and cut into Dianhong broken tea. For a long time, all the above processes have been operated manually. This process was successfully trial-produced in Fengqing and Menghai County in 1939. In November 2019, the "List of National Intangible Cultural Heritage Representative Project Protection Units" was announced, and Yunnan Dianhong Group Co., Ltd. obtained the qualification of "Dianhong Tea Production Technique" project protection unit.