1. Process flow
Fresh leaf acquisition (transportation to the factory) → withering (12-16 hours) → kneading and cutting (about 4 minutes) – fermentation (45-90 minutes) – drying (15-25 minutes) – refining (45-90 minutes).

2. Fresh leaves
The reason why Kenyan red broken tea has good quality is inseparable from its excellent variety and fresh leaf materials. Strict standards for fresh leaf picking are implemented to maintain the freshness, tenderness, uniformity, and purity of the raw materials.

3. Withering

Each red tea factory attaches great importance to the withering process. The withering workshop is spacious, bright, and well ventilated, and some buildings have withering troughs built on top and bottom floors. After the fresh leaves arrive at the factory, they are immediately weighed and transported in bags using a single track traction chain (single overhead track) to the middle of each withering trough. The leaves are manually lowered and spread evenly on the trough surface, with a thickness of about 30 cm and a spreading rate of 25-40 kg/m? Each tea factory generally has more than 40 withering troughs. The groove body is generally made of angle steel structure, the wall panel is made of plastic plate or 2-3mm thin steel plate, and the spreading layer is made of 3cmX3cm square wire mesh. The bottom has no slope and is a flat bottom or floor slab.

Lay plastic or wire mesh on the surface, and install a 4103-5595W (5.5-7.5 horsepower) axial flow fan with 4 or 6 blades at one end of the groove. The outer diameter of the fan is about 1m, and the air volume is about 33400m per hour. During the process, the fan can be turned forward and backward, and can blow and suck air, so that the groove surface blows air half the time and sucks air half the time, reducing the number of blade flips. There is a hot air duct located about 300 mm away from the fan, and a damper is opened towards the fan for heating. Generally, natural wind withering is used without heating. The withering time is about 16 hours, and the temperature in the withering room is preferably 22-24 ℃. If it is too low, heating is required.

Within this temperature range, the entire withering time is 8-16 hours, usually 12 hours. Most tea factories have conveyor belts below the withering trough to transport withered leaves to the kneading and cutting process. The moisture content of withered leaves processed by CTC machine is generally around 65%, while the moisture content of withered leaves processed by LTP machine is between 70% and 72%. The withered leaves coming down from the withering trough are bright green in color, with stems that are easily broken and have a fragrant aroma, and rarely burnt leaves. The withering workshop is clean and hygienic, with few leaves remaining on the ground and no squeezing or heating, which can meet the needs of the kneading and cutting process.

4. Rolling and cutting

Using the CTC unit processing technology, the withered leaves are transported by a conveyor belt to a vibrating cleaning machine, where they are removed of stones, iron filings, and other debris before being kneaded and cut in a 38cm diameter roller mill. The rotor of the machine is equipped with 11 sets of kneading boards (blades), each consisting of 2 pieces, arranged symmetrically. Three sets are reversed, with a speed of about 34r/min and a motor of 11563W (15.5 horsepower). There are two types of structures at the tail end, one is an adjustable cross disc, and the other is an adjustable tail vertebra, with the latter having stronger crushing force than the former. The machine can reach a leaf withering throughput of 1640kg per hour.

The outlet temperature depends on the amount of blades and the clearance at the tail end. Low outlet temperatures only increase by 0.5~1 ℃, while high ones can increase by 8~9 ℃. The tea leaves kneaded and cut by the Luotuofan machine are evenly fed onto a conveyor belt equipped with a tea hopper and a uniform impeller, and then sent to three CTC machines for further kneading and cutting. The temperature of the leaves that have been continuously chopped by three CTCs can increase by 610 ℃, but due to the short duration of force in each CTC machine, each time it passes instantly, and then it is thinly cooled on the conveyor belt and sent to the next CTC machine.

In addition, the room temperature is generally below 27 ℃, so the kneaded and cut tea leaves still maintain a fresh green color, which is beneficial for controlling the degree of fermentation. After three CTCs were continuously kneaded and cut, they were sent to the fermentation truck by a disintegrator for a total of 3.5-4 minutes, while the actual kneading and cutting time was about 1 minute.

The advantages of this kneading and cutting equipment are strong, fast, low leaf temperature, strong kneading and cutting strength of leaf tissue, sufficient crushing, fine and uniform leaf particles, which are conducive to fermentation and separation, simplify the color of finished tea, and improve the precision processing rate. The use of this combination of kneading and cutting techniques is a key technical factor in achieving strong, strong, and fresh quality of Kenyan red broken tea.

5. Fermentation

Kenya’s tea factories generally use ventilated fermentation truck devices, and a few tea factories use continuous fermentation machines. The kneaded and cut leaves are dispersed by a nail toothed roller breaker and then fed into a fermentation truck. The wet air continuously passing through the fermentation leaf layer is used to increase oxygen and humidity for fermentation, thereby improving the quality of fermentation.

The complete fermentation equipment consists of a water atomizer, a low-pressure centrifugal fan, a rectangular main air duct, and 32-36 fermentation vehicles. Each fermentation truck is loaded with about 70kg of kneaded and cut leaves at a time. The bottom of the truck is equipped with an air inlet, and the fermented leaves are spread on a porous breathable plate. After the truck is connected to the main air duct, low-temperature and humid air enters the fermentation truck through the pipeline, passes through the breathable plate, and enters the fermented leaf layer, providing very suitable oxygen, temperature, and humidity conditions for enzymatic oxidation of kneaded and cut leaves. During the fermentation process, a thermometer is used to measure the temperature every 10 minutes. The thermometer is inserted into the leaf layer at a depth of about 8cm to track and record changes in leaf temperature, making it easier for operators to strictly control the degree of fermentation according to process specifications.

While measuring leaf temperature, flip the fermented leaves once to achieve consistent fermentation between the upper and lower layers. The control and regulation of leaf temperature rely on moist air inside the duct, with a relative humidity of around 94%. The fermentation time is generally 80-90 minutes. After fermentation is complete, immediately dry it and do not let it accumulate. Before baking, the fermented leaves are broken and dispersed using a disintegrator.

When baking on fermented leaves, the leaf elephant: The leaf color is bright purple copper, uniform in color and has a fragrant aroma. When held by hand, the juice can overflow from the fingertips.

6. Drying

Most tea factories use louvered plate dryers, while a few use boiling dryers.

Drying should be carried out using a two-step drying and one-time drying method. For example, in a Marshall louver dryer, the first step of drying is carried out on a heating conveyor belt (with an inlet air temperature of 120-130 ℃ and an outlet temperature of 38 ℃). The fermented leaves are exposed to high-temperature air at around 120 ℃, which rapidly terminates fermentation and evaporates some moisture, increasing drying efficiency by 40% -50%; The second step of drying is carried out in an oven (temperature inside the oven is 92-105 ℃, outlet temperature is 53 ℃). The oven has six layers of circulating louvers, with upper and lower layers of air intake. The entire drying process takes 15-25 minutes. The moisture content of tea should be controlled at around 4.6%. This drying process of first high temperature and then low temperature is beneficial for quickly stopping fermentation, unleashing the aroma of tea leaves, maintaining strong, fresh quality, and producing tea with a more oily color.

The box of the boiling dryer is divided into several sections, each equipped with fans and air ducts. The temperature of the tea inlet section is 130-140 ℃, and the temperature of the tea outlet section is 110-120 ℃. However, the dried tea leaves appear dry and lack moisture, and the moisture content of the tea leaves discharged from the dryer is 2.5% -3%. The characteristics of this dryer are high air volume and high temperature when serving tea, which can quickly terminate fermentation.

6. 干燥

多数茶厂采用百叶板式烘干机，少数茶厂用沸腾式烘干机