Production Process of Black Tea

STAGESObjectivesMethodsMachinery and FacilitiesChanges Produced
1 WEIGHING Raw material enters the scale in order to be weighed Manual unloading, in large quantities and automatic unloading, in bulk Scale capacity 25 tn., Size: 2,8 mts wide x 7,50 mts long Manufactured by: ARCURI
2 WITHERING Partial dehydration of shoots to make them malleable for cutting. Chemical changes. Shoots enter the storage container. Air exposure under natural or monitored conditions (8hours). The withering bed is loaded. (4hours). Total duration 12 to 18 hours. Container: masonry with drilled hard wooden floor so that air can circulate, either naturally or in a controlled manner. Size: 15mts x 12,50 mts x 1mts high; 185 m2, with ventilation activated by 6 fans powered by 2HP, 1400 RPM engines.

Continuous mechanical withering bed featuring 5 parts. Total size: 35,5 mts long x 4,20 mts wide, each part is 7,10mts long x 4,20 mts wide x 0,45 mts high, each part having a scatterer. Has 5 turbines with 5HP engines each.
Goes into the next stage through a conveyor belt which is 30mts wide x 0,90mts in the belt .

Reduction in humidity by approximately 55-58%; increase in caffeine, soluble sugar and aminoacids; changes in the ratio of organic acids and the activity of enzymes in shoots and leaves.
3 MILLING Rupture and distortion of tea shoots, to enable enzyme and substrate contact. Mechanical process for tearing up, cutting, crushing, rupturing and twisting. Bronze tooth Rotorvane Shoots are cut and twisted; cellular compounds are mixed and the oxidation process begins.
4 FERMENTATION Chemical changes in leaf compounds, due to oxidation or enzymatic browning. (fermentation). Exposure to air, during 1 to 2 hours, under controlled temperature (25-30° C) and humidity (90-100%) conditions. Fermentation in continuous metallic belt fermentation, manufactured by TIME, 9 mts long x 1,97 mts wide, it has 4 31/4 HP turbines and a levelling device powered by an engine with a gearbox. Metallic belt to load drying furnace, 1,97 mts wide x 3,80 mts long.
The color changes from green to light-brownish; polyphenols oxidize and condense.
5 DRYING Stops enzymatic browning (fermentation) and dehydrate product to preserve quality in storage. Exposure to a draft of hot air for about 25-30 minutes inside a drying area, with entry temperature into furnace of about 90-105° C and a temperature of 50-55° C when removed from furnace. Conventional tea drying place, 6,60 mts long x 2mts wide, 4 floors with 240 trays with a levelling device. Heat turbine for drying furnace powered by a 15HP engine.
Humidity is reduced by approximately 3 to 4%; the product acquires its typical appearance and color. A part of the sugar content is caramelized and polyphenols are epimerized.
6 CLEANING AND SORTING Dust and fiber are eliminated; sorted into grades or types. Dry “twig” tea is broken, shredded, sorted out, mixed and packaged. 20 min. Mechanical breaking machine. Electrostatic shredder. Mechanical sorter. Classification of this batch according to size in different grades or types.