What are the processing steps of broken red tea(2)

3.Fermentation Process

The purpose, technical conditions, and physicochemical principles of red broken tea fermentation are the same as those of Kongfu black tea. Due to the international market’s demand for red broken tea to have a fresh and strong aroma, especially a strong, refreshing, and stimulating quality style with strong astringency, the mastery of the “fermentation” degree is lighter than that of Kongfu black tea, that is, the enzymatic oxidation degree of polyphenolic compounds is lighter.

(1)Fermentation method

a. Natural fermentation

It is to evenly spread the kneaded and cut leaves in a fermentation box, place them in a constant temperature, high humidity, and well ventilated fermentation chamber, and let them ferment naturally. The fermentation box is preferably made of wood, bamboo, or aluminum products, which are easy to wash. Spread to a thickness of about 4cm, and thicken appropriately in low temperature seasons. Room temperature is 22-25 ℃, with a relative humidity of over 90%. The fermentation time is related to the aging and crushing season of the leaves, as well as the temperature and humidity of the fermentation room. In production, it is advisable to flexibly control the fermentation according to the situation and use moderate light fermentation. The traditional method generally does not require separate fermentation due to the long kneading and cutting time.

b. Cooling, humidification, and aeration fermentation equipment

There are fermentation trucks and continuous fermentation machines, which can be used by tea factories with conditions. The temperature should be between 22-26 ℃ for leaf temperature, with a relative humidity of over 95%. The leaf thickness should be 4-6cm, and the fermentation time should be 30-60 minutes for flipping the leaves every 10 minutes. Using a small car for breathable fermentation, the thickness is controlled at around 40cm. For large leaf species with high rates of damage to tender leaves and leaf cells, as well as good fermentation performance, and during high temperature seasons, they should be spread thinly. Conversely, when spread thinly, the leaves can be slightly thicker.

(2) Fermentation degree

a. Fermentation degree

The degree of fermentation should be moderately mild. To identify the degree of fermentation, mainly by smelling the aroma, combined with observing the leaf color, it is considered moderate when the leaf color is yellow green, the grassy air has basically disappeared, and there is a slight fragrance. In addition, based on the fermentation equipment used by each factory, combined with factors such as leaf quality, moisture content, and temperature, the degree of fermentation can be mastered. When the summer temperature is high and there is no cooling or humidification equipment, in order to prevent the quality from being affected by the fermentation speed being too fast, fermentation is usually not necessary and immediately dried in a dryer; If the dryer is insufficient, it is necessary to flip the leaves more and spread them as thinly as possible, and place them in a cool place for drying.

b. Fermentation precautions

The screened bottom tea should be placed in order of variety, grade, and tea number, and the fermentation time should be marked from beginning to end. The leaf layer should be loose and flat, and the thickness of the spread leaves should be determined according to the cooling and humidification conditions and climate of the fermentation chamber. Pay attention to maintaining the cleanliness and hygiene of the fermentation chamber and fermentation tools. It is required to clean the fermentation chamber and tools 1-2 times a day. Due to the consumption of a large amount of oxygen during fermentation, doors and windows should be opened regularly and fresh air should be replaced. If the doors and windows are closed and there is insufficient oxygen supply, it will hinder the fermentation process. At the same time, a large amount of CO is released during fermentation, which deposits in the lower layer of the fermentation chamber and is not easily discharged outside. Therefore, it is necessary to install a low-power exhaust fan in the fermentation chamber. Observe and control the temperature, humidity, and fermentation degree of the fermentation room at any time. The fermentation and drying processes should be closely coordinated to balance production. After drying one plate of fermented leaves, transport the next plate. Do not stack the fermented leaves in the drying workshop waiting for drying. If there is a delay in drying during production, it is necessary to compress the cutting cycles and strive to balance the fermentation and drying processes.

4. Drying Process

The purpose, technology, and physical and chemical changes of dried leaves are the same as those of Gongfu black tea, with only differences in specific measures.
Through the three processes of withering, kneading, and fermentation, the quality of broken red tea has been basically formed. It is necessary to rapidly inactivate the activity of enzymes at high temperatures to fix the formed quality. Due to the small particles and fast fermentation progress of broken red tea, it is necessary to master the techniques of high temperature, fast speed, and thin spreading during drying. The temperature should be high, the operation should be fast, and the leaves with moderate fermentation should be quickly roasted to avoid excessive fermentation.

(1) Drying method

a. High temperature rapid one-time drying method

If the moisture content of the fermented leaves is around 60% and the air temperature is between 110-115 ℃, use fast or medium speed with a leaf thickness of 0.5cm. If using a hot conveyor belt dryer or a drying machine with high and low temperatures, the air temperature should be appropriately reduced. Once dried, the tea has a high aroma and a dark and smooth appearance. It is easy to operate, but the temperature is not easy to control, which can easily produce high heat tea.

b. Secondary drying

Intermediate cooling (used for tea leaves and tea tails), with a firing temperature of 110-115 ℃, fast or medium speed drying, and a leaf thickness of 1cm. After the leaves are removed from the machine, cool for about 15 minutes. The foot fire temperature is 90-100 ℃, and the leaves are dried at fast or medium speed with a thickness of 2 cm. After secondary drying, the aroma of the tea is long-lasting, and the quality is relatively stable after drying. It is not easy to produce high fire tea, but the freshness is easily damaged. In addition, due to the cooling process during secondary drying, the moisture content of the leaves will be evenly distributed, and the drying effect is better than that of primary drying. However, whether it is a primary drying or a secondary drying, the maximum drying temperature (air temperature) must not exceed 120 ℃, otherwise it will cause high heat in the tea leaves

(2) Drying degree

The moisture content of Maohuo tea should not exceed 20%. High moisture content is not conducive to quality and can accelerate oxidation. The moisture content of Zuhuo tea should be below 5%.

(3) Precautions for drying

Operators should correctly grasp the fire temperature, leaf spreading thickness, and louver running speed, regularly check the aroma and moisture content of the raw tea, prevent high fire and burnt tea, and ensure the quality of the raw tea. Before starting up, the residual leaves, tea ash, tea hair, etc. on the louvers in the oven should be cleaned to prevent blockage of the holes and affect the tea drying effect.

If not cleaned, residual tea leaves will become charred due to prolonged and high temperature roasting, causing a burnt tea flavor. If mixed with wet tea, it will affect the quality. 15 minutes before starting the dryer, stabilize the furnace temperature at 120 ℃ or above. When starting the high-efficiency fan, maintain the air temperature at the inlet at 115-118 ℃. Distinguish between tea batches, tea numbers, and place them on the top and bottom of the machine to prevent confusion. In case of tea with high moisture content or deterioration, it should be stored in separate piles and handled separately. The tea leaves leaking from the oven louvers should be promptly swept out, usually every 15-20 minutes.

If the scanned tea has high moisture content and uneven dryness and wetness, it should be dried and reheated, and should not be mixed with dried tea leaves. When there are phenomena such as high temperature, burning, and smoke smell during drying, the blower should be immediately turned off to stop blowing hot air. At the same time, stop conveying the wet billet, open the oven door, continue running the louver board, remove all the deteriorated tea in the oven, and store it in another pile. After checking and correcting the causes of these phenomena, continue to brew tea. When the blower stops running, the furnace temperature should be immediately reduced to prevent deformation of the heating tube. The drying workshop should be kept clean and tidy, and the tea on the ground should be cleaned in a timely manner; The hair strands and tea ash flying out of the oven should be swept up at any time and treated separately to prevent mixing into the good tea.