Modern Matcha Processing Technology and Equipment

The processing of traditional matcha mainly includes two processes: tea grinding and crushing. Fresh leaves are first processed into ground tea, and then matcha is formed through grinding. The earliest tea mills used in Japan were all imported from China, known as “Tang tea mills”, and Japanese products only appeared in the mid-15th century. Japan started early in the research of modern matcha processing technology and equipment. After years of catching up, China’s production technology and equipment have fully reached the level of Japan’s technology.

Tea grinding processing technology

In terms of tea processing technology, the main steps are: fresh leaf spreading → green leaf flow meter (fresh leaf cutting and screening) → steam withering → cooling loose tea → baking and drying → removing stems and impurities → foot drying and aroma enhancement. The initial tea can only be further ground and crushed into matcha products after undergoing air selection, impurity removal, and cutting treatment

Main processing equipment for matcha

(1) Fresh leaf storage and pre-processing equipment

Fresh leaves are usually stored in cart-type green tea storage equipment. When necessary, atomizers are used to cool and preserve the fresh leaves to solve and stabilize the quality of fresh leaves during peak season. Fresh leaves are cut and screened by cutting machines using methods such as cross-cutting and vertical and horizontal cutting to avoid problems such as uneven withering caused by inconsistent sizes of machine-picked leaves during subsequent processing.

(2) Withering equipment

Currently, the fresh leaf withering technology mainly includes drum withering, hot air withering, steam withering and microwave withering. Steam withering is one of the fastest, most thorough and most uniform withering methods, which can better preserve chlorophyll.

Traditional steam withering machines use 100-105℃ steam withering for 10-20 seconds. Steam hot air withering machines and stir-fry steaming machines are new steam withering machines developed in recent years. When the steam hot air withering machine is withering, the leaves are withering in sections during the vibration process. Steam withering is used at the front end and hot air withering is used at the back end. The withering is uniform, without overlapping leaves (yin and yang sides), and rain leaves can also be withering in time. There is no need for professional personnel to adjust the equipment. Only the steam flow rate needs to be fine-tuned according to the tenderness of the raw materials, which greatly improves the withering efficiency. However, the machine is relatively large and requires two energy systems. The stir-fry steam fixing machine uses superheated steam and humidified hot air generated by ultra-high temperature generating equipment to complete the fixing of green tea. It has a wide range of uses and can be used to process products with stir-fried green tea flavors as well as products with steamed green tea flavors.

(3) Cooling equipment for loose leaves

There are four main methods for cooling loose leaves: high-temperature hot air dehydration, low-temperature strong air dehydration, natural air shower dehydration, and high-speed centrifugal dehydration. Currently, natural air shower dehydration is more commonly used in production. This involves rapidly blowing cold air 4 to 5 times to a height of about 6 meters for steam-cured leaves to loosen and cool them, remove surface moisture, and reduce heat.

(4) Matcha drying equipment

At present, the drying process of matcha tea is mostly still completed in traditional brick type tea rolling furnaces. A tea stove is a drying room made of bricks with side walls (about 13m long, 2m wide, and 3m high). The heating source comes from the bottom layer of oil or natural gas burning red iron plates. The drying room uses convective hot air released from the exhaust pipe to dry the leaves. There are generally 4 layers of mesh stainless steel conveyor belts inside the tea stove, with blades stacked on the belt, about 20mm thick. They move forward on the multi-layer belt by air exchange and pass through 3 stages for about 20 minutes. The first stage is at 170-200 ℃, the second stage is at 130-160 ℃, and the third stage is at 100-120 ℃, achieving preliminary drying.

The high amino acid content of fresh leaves develops a unique flavor after being roasted by radiation heat. This is why matcha dried in traditional brick-built tea ovens has a vibrant color and distinctive aroma. The shortcomings of traditional drying rooms are obvious: they are too large to be moved, the drying temperature cannot be precisely controlled, energy consumption is high while heat efficiency is low, and the withered leaves tend to stick and overlap on the conveyor belt, causing them to burn. Improved traditional drying rooms utilize a new, more efficient heating cast iron, add an infrared coating, and replace the moisture vent with a hand-cranked, arbitrary positioning device for easy opening and closing, reducing heating time by 30%. The stainless steel mesh conveyor belt has been replaced with a longitudinally woven steel wire mesh, which not only effectively improves its bending resistance and more than doubles its service life, but also dries the tea leaves faster, resulting in a richer aroma in the finished tea.

In recent years, a far-infrared matcha drying oven has been developed based on traditional brick fired tea stoves. Through modular segmented baking and precise control of temperature and light source sections using PLC, the combination of far-infrared drying and hot air drying is achieved. The withered leaves are transported by a single-layer mesh belt in the far-infrared tea rolling drying oven for 5 minutes to complete drying, which is four times more efficient than traditional tea rolling ovens. The far-infrared matcha drying oven not only allows the product to continue the traditional drying flavor of the drying room, but also makes the processing site cleaner and more hygienic.

(5) Stem and leaf separation equipment

After the drying process, the moisture content of the leaf part drops to about 10%, while the moisture content of the leaf stem is still 50% to 55%, and the toughness is still not easy to break. Therefore, the stem and leaf separation process is required to remove the tea stems, leaf veins and broken leaves. The main equipment for the stem and leaf separation process is the stem and leaf separator, which has a semi-cylindrical metal mesh structure. The built-in spiral knife peels the leaves from the stems when rotating. The peeled tea leaves pass through the conveyor belt into the high-precision air separation machine for air separation. The newly developed leaf vein separation vertical cutting machine is widely used in production. The vertical cutting machine is equipped with two cutting wheels. When the tea leaves pass through the gap where the blades intersect, the left and right blades can separate the leaf veins attached to the leaves. The separated leaf veins will not be cut off, and they can be easily separated in the subsequent wind separation machine.

(6) Drying equipment

After the leaves and stems are separated, they need to be dried in different dryers due to the different moisture contents of the leaves and stems. Generally speaking, the leaves are dried with hot air at 60-70℃ for about 10 minutes to produce the primary rolled tea. The traditional dryer uses a perforated chain plate to transport the tea leaves in layers and uses a hot air source for drying. Its disadvantages are that the temperature control is not accurate; the aperture of the flap is large, the material is not evenly discharged, and the consistency of the tea leaves in the later stage is poor; the leaf processing is open and unhygienic. The improved new hot air dryer uses a fine-hole flap to transport the tea leaves in sections, and the hot air enters different layers in sections. It uses PLC to control the temperature in different layers. It is more suitable for drying small teas. The feeding area is separated from the drying area, making the drying process more hygienic and improving the food safety during the rolled tea processing.

(7) Post-processing equipment

Post-processing equipment mainly includes tea cutting machines, circular sieving machines, air separation machines, and aroma extraction machines. Before being ground into matcha, the primary ground tea needs to go through a refining process such as cutting, sieving, and air separation to further remove tea stems, leaf veins, yellow flakes, and impurities, forming uniform fragments of 0.3 to 0.5 cm in size. If necessary, it needs to be dried again.