Wuyi Rock Tea is a traditional Chinese Tea renowned for its unique rock aroma and flavor, growing in the crevices of rocks. It is a semi-fermented green tea, with Dahongpao being one of its famous varieties. This article outlines the basic operational techniques and key points of each step in the refining process of Wuyi Rock Tea, aiming to provide guidance for production practice.
Refining Techniques for Wuyi Rock Tea
The refining of Wuyi Rock Tea involves processing raw tea into finished tea. The primary focus is to remove stems, fragments, and foreign matter, improve the uniformity and purity of the tea's appearance, and enhance its quality. The refining process comprises 13 steps: grading and sorting, preliminary sorting, sifting, cutting and shaping, winnowing (air selection), secondary sorting, blending, Baking, cooling, packing (into boxes or barrels), storage, blending, additional baking, and packaging.
Flow Chart of Wuyi Rock Tea Refining Process
Grading and Sorting
Grading and sorting are primarily for preparing raw tea for blending. Based on sensory evaluation results using the national standard samples or trade samples of Wuyi Rock Tea, raw teas are sorted according to their origin, variety, season, and quality.
Specific steps for sorting raw tea: Samples are taken from the same batch of raw tea, mainly evaluating their aroma and taste. The best quality is combined into the first pile (top pile), also known as the head pile; slightly inferior quality is combined into the second pile (middle pile); the lowest quality is combined into the third pile (bottom pile). Defective raw teas are handled separately; if they belong to single-clone or named clones, they are sorted into separate piles and processed through sifting and winnowing on sunny days.
Preliminary Sorting
Preliminary sorting refers to the first sorting after grading and sorting or additional baking, which includes mechanical and manual sorting. Mechanical sorting equipment mainly includes stepwise stem removers, electrostatic stem removers, and color sorters. Currently, color sorters are widely used. Their principle is to work under the action of light, output signals based on the intensity and color differences, and drive electromagnetic valves to blow out differently colored stems, fragments, and other impurities. The remaining tea that meets the color selection requirements falls into the finished chamber of the receiving hopper. After sorting with the color sorter, some stems, fragments, and other impurities still need to be manually removed.
Color Sorting Machine for Sorting
Sifting
The purpose and function of sifting is to distinguish the size, length, thickness, and weight of the tea leaves, which not only decorates the appearance of the tea but also facilitates subsequent air selection and secondary sorting. Circular sieves are commonly used to distinguish the size or length of the tea leaves, shaker sieves to distinguish flatness and thickness, and floating sieves to distinguish lightness and heaviness.
Flat Sifting
Shaker Sifting
Cutting and Shaping
Due to the uneven length and size of the tea leaves, they must be broken, cut, and shaped to achieve uniformity, which facilitates packaging. Coarse outer leaves are cut using a cutter or manually shaped. For Wuyi Rock Tea, a toothed cutter (also known as a serrated cutter) is generally used to cut long outer leaves. Manual shaping involves breaking the long tea leaves with both hands, repeatedly sifting and lightly pinching them to complete the shaping process.
Winnowing (Air Selection)
Winnowing (air selection) is mainly used to distinguish the lightness and heaviness of the tea leaves, removing yellow fragments, dust, and other light impurities. It is generally divided into manual winnowing and air selection.
Manual Winnowing: Hold the Sieve at about one-third of its length with both hands, forming a triangle with your abdomen. Use your wrists and arms to move the sieve up and down, throwing the tea into the air. As the tea is thrown up, push the sieve outward, and when the tea falls, pull it back inward. The heavier tea falls toward the rear of the sieve, while the lighter tea falls to the front of the sieve, and the wind causes the light particles to fly out, completing the winnowing process.
Winnowing
Air Selection: In production, a blowing-type air selector is generally used, which has a lower outlet and a horizontal outlet. The lower outlet is further divided into the main outlet, sub-outlet, and secondary sub-outlet. The tea from the main outlet is tightly rolled and high-quality, considered the main body or clean tea. The tea from the sub-outlet and secondary sub-outlet is sorted again based on its condition. The tea blown out of the horizontal outlet is called “fan tail,” consisting mainly of fragments, stem skins, dust, and other particularly light impurities.
Air Selection
Secondary Sorting
Secondary sorting is the second sorting of the tea after sifting and winnowing (air selection), also known as fine sorting. It involves removing any remaining stems, triangular fragments, seeds, and other impurities that were not removed during preliminary sorting and winnowing (air selection), improving the purity and appearance of the tea.
Blending
The method of manual blending is “level layer spreading, vertical division for material taking, multiple divisions for blending, and mixing evenly.” Each grade of tea is layered from the second-grade tea to the seventh-grade tea, from bottom to top, on the blending platform. Then, a blending rake is used to rake straight down from the top, mixing the different grades of tea evenly, facilitating subsequent baking.
Manual Blending
Baking
The quality of Wuyi Rock Tea is closely related to its unique baking process. Temperature is the key factor in determining the quality of baked tea, which varies based on the type, condition, and processing method of the tea, generally controlled between 100-145°C. During spring and Winter, when temperatures are low, the baking temperature should be moderately increased and extended; during summer and autumn, when temperatures are high, the temperature should be appropriately reduced and shortened. The baking temperature can differ by around 10°C between spring and winter and summer and autumn. See the following table for specific baking temperature requirements for different raw materials.
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