Views: 0 Author: Site Editor Publish Time: 2026-04-29 Origin: Site
The raw material of instant tea is tea leaves, which go through the processes of raw material blending, extraction, separation, concentration, formulation, sterilization, drying, final blending, and packaging before becoming the finished instant tea product.
It is unlikely that a single type of raw material is used for a particular instant tea. Using only one type of raw material results in a flat flavor profile and also poses a greater risk of supply interruption. Moreover, if a certain instant tea becomes very popular, a single-origin recipe is easy to copy. For these reasons, blending is always chosen for instant tea raw materials. The basic principle of blending is to meet flavor requirements while keeping costs as low as possible. This can involve blending tea leaves from different suppliers, different origins, or different tea types. Generally, the raw materials for a given instant tea powder are limited to 3 or 4 types. Too many varieties complicate procurement, while too few typically cannot resolve the issues mentioned above.
The principle of extraction is the same as daily tea brewing: using hot water to dissolve the water-soluble components from tea leaves. The key parameters are water temperature, water-to-tea ratio, and extraction time. How these parameters are controlled depends on product flavor, production efficiency, and yield. In most cases, it is difficult to optimize all three aspects simultaneously, so R&D technicians must weigh the trade-offs and find the optimal compromise.
The most mainstream extraction equipment currently includes countercurrent extraction troughs and extraction tanks, as well as the relatively newer countercurrent extraction columns, which operate on the same principle as countercurrent extraction troughs. In recent years, domestic equipment manufacturers have been imitating the rotary disk distillation column from FT of Australia, hoping to apply it to plant extraction (including tea) in China. However, so far they have only learned the basics, and actual application results are unsatisfactory. Erchun conducted two years of follow-up research on FT's SCC and rotary disk distillation column, finding that the equipment has high requirements for raw materials, that domestic imitations are too crude, and that operational limitations are significant. These new types of equipment are not without advantages, but they require the buyer and manufacturer to form a dedicated team to work together on continuous improvement and upgrades—something that generally no one is willing to do.
The advantage of the extraction trough is its ability to support continuous production, especially for large-volume products. Extraction tanks, on the other hand, offer more convenient parameter control, particularly during trial production when parameters need to be adjusted on the fly—the extraction tank can adapt flexibly.
Extraction troughs and tanks are also being continuously upgraded, for example by adding tea leaf pre-wetting devices, recirculation devices, ultrasonic devices, etc. Equipment manufacturers often boast that their devices include ultrasonic systems, claiming they greatly improve extraction efficiency. However, the enhancement from ultrasound in instant tea production is negligible. Especially considering the cost of the ultrasonic device, the ultrasonic generator is essentially a chicken rib—nice to have but ultimately useless.
Separation mainly involves centrifugal separation and membrane separation. The most commonly used equipment for centrifugal separation is the horizontal decanter centrifuge and the disc stack centrifuge, often abbreviated as decanter and disc centrifuge. The decanter centrifuge is suitable for preliminary centrifugal separation, with a much higher throughput per unit time than the disc centrifuge, so typically one decanter is followed by three disc centrifuges.
Membrane separation generally refers to ultrafiltration (UF) membrane separation. This process removes large molecules that centrifuges struggle to handle, such as proteins and cold-break complexes. Ultrafiltration membranes are typically used for instant tea powders that have clarity requirements. Hollow fiber ultrafiltration membranes are common, available in outside-in or inside-out configurations. Depending on the membrane material, options include PP, PE, PES, PVC, and PVDF. Additionally, considerations include flow channel design—parallel or diamond-shaped channels—and the appropriate channel spacing. The specific choices depend on product requirements and cost considerations.
The biggest challenge in membrane use is preventing fouling, and once fouling occurs, how to clean it effectively. Alkali and acid solutions are generally used for cleaning. However, determining which alkali, which acid, what concentration, and how many cleaning cycles are appropriate is the critical part. I spent six months studying this area and eventually found relatively suitable acids, alkalis, and cleaning procedures. Unfortunately, this aspect is often overlooked in instant tea production, and very few people are willing to put in the hard work to study it properly. The result is that a set of membranes may need to be scrapped after just over six months. With proper cleaning and maintenance, ultrafiltration membranes can last 1 to 2 years.
Concentration is the process of increasing the concentration of tea extract to reduce the burden on the subsequent drying step. The most commonly used concentration equipment in instant tea production are triple-effect evaporators and reverse osmosis (RO) membrane concentration systems. Triple-effect evaporators come in falling-film and rising-film types, and based on their structure, they can be further divided into plate-and-frame and tubular types. Each has its own advantages and disadvantages; the specific choice depends on budget and product characteristics.
The application of reverse osmosis membrane concentration in instant tea production was adapted from the wastewater treatment industry, but its mode of operation is exactly the opposite of how it is used in water treatment. Many membrane system manufacturers have difficulty understanding this—sometimes different professions are truly worlds apart. RO membranes are typically spiral-wound membranes. Their material composition is less complex compared to ultrafiltration membranes, and the key parameters are operating pressure and operating temperature. These also require long-term testing. However, many companies today select membranes based largely on data and explanations provided by manufacturers, followed by executives making decisions off the cuff. Very few are willing to spend the time conducting extended tests.
Before sterilization, the concentrate must be formulated according to process requirements—whether to add flavors or other ingredients, and what the final concentration should be. This step is relatively simple and mainly depends on the care and precision of the operator. Some workers are meticulous and weigh ingredients accurately; others are careless, acting as if it doesn't matter whether they add a little more or a little less.
The formulated concentrate then undergoes sterilization. The commonly used equipment for sterilization includes coil-type sterilizers and tubular-type sterilizers. Coil-type equipment is simple in design and easy to operate. Tubular-type sterilizers, when properly parameterized, provide better sterilization results than coil-type units, but the equipment is more complex. The key parameters for sterilization are sterilization time and sterilization temperature, which also involve the ramp-up time, holding time, and cooling time. When selecting parameters, one can first calculate based on thermodynamic formulas and then conduct tests to determine the final parameters.
The conventional drying method is spray drying, which offers high efficiency. Currently, a small number of instant teas use vacuum freeze drying, which provides better flavor than spray drying, but the drying time is long and the cost is higher. Large-scale spray drying equipment is generally custom-made by manufacturers, typically using pressure nozzles, while small to medium-scale units may use centrifugal atomizers. Factors such as the height-to-diameter ratio, number of atomizers, air exhaust method (top exhaust or bottom exhaust), and cleaning method must be considered during equipment design. The specific settings for inlet air temperature and feed rate depend on product requirements and also need to be determined through testing. Freeze drying mainly involves establishing a freeze-drying curve: pre-freezing time, pre-freezing temperature, primary drying temperature, primary drying time, secondary drying temperature, secondary drying time, holding temperature, and holding time. These parameters affect the entire freeze-drying time and energy consumption—in short, the cost.
Our vacuum belt dryer is very suitable for drying tea powder, especially for instant tea powder that has high requirements for preserving flavor, color, and heat-sensitive components. The drying temperature can typically be controlled between 35°C and 90°C, or even 20°C to 80°C, maximizing the retention of tea aroma, color, and heat-sensitive components. It enables continuous feeding and discharging of uniform tea powder, with a short drying time (discharge within 30–90 minutes), high production efficiency, and suitability for industrial-scale batch production. Drying under vacuum conditions excellently preserves the color, aroma, and taste of the tea powder while preventing oxidative degradation. The dried tea powder exhibits good flowability and excellent solubility (instant properties). Technical literature from multiple equipment manufacturers clearly indicates that this equipment is widely applicable to the drying of "instant tea" and "tea powder," making it a mature process within the industry.
The dried instant tea powder is generally referred to as a semi-finished product. To turn it into a finished product, further blending is required based on the test results of the semi-finished product. Because indicators such as tea polyphenol content are not constant across batches, and the flavor is not exactly the same, blending—also called final blending or mixing—is necessary to achieve a qualified finished product.
After blending comes packaging, where the product is packaged into corresponding specifications according to requirements. The equipment involved includes blenders (mixers) and packaging machines. Blenders come with different stirring configurations; the choice mainly depends on practicality and budget.
Packaging machines have seen significant upgrades in recent years. In the past, most work was done manually—manual weighing, manual vacuum sealing, and manual tape fastening. Nowadays, new factories increasingly opt for automated packaging machines. However, are they so automated as to completely replace humans? Not yet. The biggest advantage of manual labor is flexibility. Machinery is highly efficient when handling single, large-volume products, but it cannot match the flexibility of human workers. The choice between manual and automated packaging depends on product type, production volume, and the company's budget.
The overall process flow and main equipment involved in instant tea production are as described above. However, there are far too many details to cover. Establishing a good instant tea production line and setting sound process parameters for an instant tea product require extensive testing upfront. Over the next ten years, this work will still rely on human effort—AI has not evolved to the point of being able to handle these tasks. To be honest, conducting these tests is extremely arduous. The testing environment is hot, humid, and noisy; sometimes finding a suitable parameter means spending several days straight in such conditions. As a result, among the second generation of tea deep-processing technicians, very few have such a comprehensive understanding of the full range of equipment and processes—you could count them on one hand.
This type of fundamental research has a long payback period, so bosses are reluctant to invest money in it. The younger generation is unwilling to work on the production floor, and the older generation is no longer willing to teach—or to be fair, some of them are only half-competent themselves, so how could they teach others? But then again, some things are simply determined by fate.
