CONTINUOUS FERMENTING MACHINE helps to eliminate microbial contamination in tea. Micro organisms occur as contaminants during tea processing due to the presence of a layer of fermented juice on the processing machines and other equipments. The CFMs consist of a tray made up of conveyor racks with three to four tier system like “quality” drier arrangements. The fermented dhools travel in a thin layer on the conveyor rack. Above or below the tray, UV lamps are fitted which are used to kill the external bacteria and triggers the activity of polyphenol oxidase, thereby hastening the biochemical reaction. Bright infusions are obtained in the continuous fermenting machine. This machine is generally used for NRC tea manufacture. In RC tea manufacture googhie sifter is used before CFM for granulation of tea.

DRYING The keeping quality of tea mainly depends on the drying technique and the final moisture content in the made tea. The objectives of drying are to terminate the biochemical changes and to remove moisture to achieve better keeping quality. During the process of drying, water is removed from the fermented leaf and its colour turns from coppery red to black and fermentation is arrested.

ECP DRIER The Endless Chain Pressure type driers consist of two or three individual tray circuits. When the leaf is fed into the feeding circuit, the spreader spreads the leaf uniformly on the tray. As soon as the leaf completes the run on top circuit, the tray carrying leaf are automatically tilted at the end of the circuit and the leaf falls on the mid circuit where direction of tray movement is opposite to that of top circuit. Thus the leaf is subjected to gradual high temperature from top to bottom circuit and drying is completed when the leaf reaches the bottom circuit. The total drying time is 20-22 minutes. The output of the drier is 200-250 kg made tea with the feeding moisture level of 55%. The inlet and exhaust temperatures may be maintained at 100°C and 55°C, respectively.

FLUID BED DRIER consists of drying chamber, plenum chamber, air flow damper and dust collectors. The drying chamber is separated by a perforated grid plate through which high pressure hot air from the plenum chamber gets into the drying chamber for fluidisation. The plenum chamber is divided into four zones which have individual air control valves. These valves control the quantity of air to the individual zone and the direction of hot air entering the control dampers. At the top of the drying chamber two centrifugal exhaust fans are fitted with cyclone, one for refiring and the other for dust extraction. When the fermented dhool is fed into the drying chamber in the first zone it gets fluidised. With the help of pressurised hot air, water is removed by evaporation. The inlet and exhaust temperatures for FBD may be maintained at 250°F to 260°F and 150-160°F for achieving better quality.