Tea Grades
Article | Black Tea

Tea Grades

Tea Grading

The final step in the tea manufacturing process is grading. The tea leaves brought from the field to the factory are finally divided into different grades. While traditional machines are used to grade tea, modern machines are now available in factories.

the use of modern technological machines for the tea classification today saves time and labor. tea grades vary depending on their manufacturing process.

The grades according to the different production processes used in the production of black tea are as follows.

  • Orthodox – Rotorvane Tea  Manufacture  
  • Pure  Orthodox Tea  Manufacture  
  • C T C Tea  Manufacture 

Objectives of Tea Grading

  • Separation into various shapes and size  for trade requirement
  • Size reduction of oversize to form acceptable grades
  • Cleaning of grades
  • Preparation for marketing & transport of the product
Grading according to Particle Size
Grading according to Particle Size
Grading according to Particle Shape
Grading according to Particle Shape
Grading according to Cleanliness
Grading according to Cleanliness

Orthodox – Rotorvane Tea  Grades

  • PEKOE
  • BOP – Broken Orange Pekoe
  • BOPF -Broken Orange Pekoe Fannings
  • DUST 1 –
  • DUST
  • Fannings 1

Pure  Orthodox Tea  Grades

  • OP – Orange Pekoe
  • OP 1 – Orange Pekoe 1
  • BOP – Broken Orange Pekoe
  • BOPF – Broken Orange Pekoe Fannings
  • FBOP – Flower Broken Orange Pekoe
  • BOP 1 – Broken Orange Pekoe 1
  • FBOPF – Flowery Broken Pekoe Fannings
  • FBOPF 1 – Flower Broken Orange Pekoe Fannings 1
  • Pekoe
  • Pekoe 1
  • BOP 1A
  • BM
  • BT
  • Fannings 1
  • FF 1
  • FF
  • FF Sp

CTC Tea Grades

  • BPL
  • BPS
  • BP1
  • PF1
  • PD
  • Dust 1

There are two types of grades in tea production main grades and off grades. Main grades are produced from the upper parts of the tea flush and Off grades are produced from the lower part of tea flush.

In addition to the above grades, there are separate grades under Green tea, white tea, and oolong tea.

Below are some of the machines used in the production of black tea and some details about them.

Machineries Used for Grading

  • Machines used to separate particles by size –Middleton, Chota Sifter, Michie Sifter
  • Machines used to separate particles by weight  – Winnower
  • Cleaning Machinery -Fibromat, Winnower, 3T, Colour Separator
  • Particle size reducing machinery -Tarry Nipper, Tea Cutter

01 MYDDLETON

  • Two Bubble trays used ( 4mm-7mm, 5mm-8mm etc.)
  • Oscillatory motion in vertical plane (Michie)
  • Used to separate dhools and big bulk in to 03 fractions (SSF,MSF,LSF) in the initial stage of grading.
  • Most grades passing through Middleton just before packing for even the grade
  • Typically 200-220 oscillations per minute
  • Feed rate need to be adjusted carefully for  better performance
  • Send the tea layer just to visible the bubbles

02 SUCTION WINNOWER

  • All the sifted teas passing through the winnower to separate by weight.
  • Same grade’s heavy & secondary particles separated v Flaky particles also removed (Cleaning)
  • Belt conveyor is essential for better performance
  • Keep the extractors closed by using weight adjustors

03 Color Seperetor

  • Any sample before color separating passes through the winnower.
  • Even feeding is very important.
  • Tune-up the machine for every grade.
  • Before color separating clean much as possible by other cleaning machines.

04 Chota Shifter

  • Suitable to separate nearly spherical particles ( FBOP, Pekoe, FF,FF1,Dust)
  • Not suitable for extract leafy grades
  • Use with a feed conveyor for better  performance
  •  Normal speed 150-oscillations per minute

05 Michie Shifter

  • Single tray sifter
  • Oscillatory motion in a vertical plane
  • Having the chance to jump forward for particles
  • Suitable for leafy grades like OPA,  OP, OP1, BOP 1, Pekoe
  • Output, Uniformity of particles governed by the speed

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Reference

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