Detailed Explanation of Instant Tea Processing Methods and Production Techniques

Instant tea, also known as extracted tea, dates back to the 18th century when European tea merchants imported from China a dark strip-cake made from concentrated tea extract, each piece weighing about 6 to 7 grams, which dissolved into a drinkable tea. This may be the prototype of today's instant tea. Instant tea is a deep-processed tea product with a wide range of raw material sources, not limited by production area. It can be made directly from low- to mid-grade finished black or green tea, or from fresh leaves or semi-finished products. In instant tea production, the selection of raw materials is crucial, as it not only has an important impact on quality but is also closely related to economic benefits. Teas from different regions with different characteristics, seasonal teas, or teas of different grades can be appropriately blended. After the raw materials are selected, the tea leaves should be appropriately crushed to increase the contact surface between the tea and the solvent and improve the extraction rate of soluble substances. Whether it is instant black tea or instant green tea, the production process mainly consists of: material selection and processing, extraction, purification, concentration, drying, and packaging. The flavor of instant tea is closely related to the extracted components, and the single-barrel intermittent extraction method is preferable. During extraction, the pre-weighed tea leaves can be poured into an extraction barrel lined with a cloth bag, a certain proportion of boiling water added, the lid put on, and after steeping for 10 to 15 minutes, the liquid is released and centrifuged. Experiments have shown that the larger the tea-to-water ratio during extraction, the higher the extraction rate. Generally speaking, a tea-to-water ratio of 1:6 to 12 during extraction is better. The number of extractions varies according to the tenderness of the raw materials; as the tenderness of the raw materials decreases, the extraction amount correspondingly increases, and low-grade tea only needs one extraction. With proper extraction methods, the tea's aroma is pure, the taste is strong, and the liquor color is yellow-green and slightly cloudy. Purification is for removing impurities and sediment. At present, there are mainly two purification methods: one is physical methods, such as centrifugation and filtration; the other is chemical methods, which mainly involve appropriate chemical treatment of the precipitated portion of cold-insoluble substances to promote the conversion and dissolution of these substances. The purified extract is relatively dilute, so it must be concentrated to raise the solid content to about 20% to 40%. This can both improve drying efficiency and help obtain low-density granular instant tea. Drying not only affects the internal quality of the product but also has an important impact on the product's appearance and instant solubility. At present, vacuum drying, spray drying, and freeze drying are commonly used. Among these, spray drying has high efficiency, the product has good solubility, and the cost is low, so it is a commonly used method. The drying result should control the weight of 100 milliliters of instant tea to about 15 grams, with a particle size controlled at 0.2 to 0.5 micrometers. The final step is the packaging of instant tea. Because instant tea is both sensitive to off-flavors and prone to moisture absorption, even slight moisture absorption can cause caking and deterioration, loss of aroma, and discoloration of the liquor. Severe moisture absorption can turn it into an asphalt-like state, making it undrinkable. For this reason, when packaging instant tea, air-conditioning equipment must be provided to control the temperature of the packaging workshop below 20°C and the relative humidity below 60%. Lightweight packaging materials should be used, commonly lightweight bottles, aluminum foil plastic bags, and the like. In addition, during instant tea processing, in addition to avoiding aroma loss through processing technology, aroma recovery and flavor blending procedures are often also required.