Primary Grades---
When we finish processing tea, its comes out of Drier in mixed sizes and shapes.
Then it is graded according to its sizes. Thease are called Tea Grades
Top of the list is BOPL-- Its the biggest size in CTC tea. Good in aroma, colour but light in liquor.
It Uses six holes per inch in a sorting mesh.

>BPs-- It comes after BOPL in size but taste generally better than BOPL.
It gives better colour, better liquor and sufficient aroma in comparison to BOPL.
It uses8 holes per inch in a mesh.

BOP-- It comes after BOPs in size but taste generally better than BOPL.
It gives better colour, better liquor and sufficient aroma in comparison to BOPs.
It uses 10 holes per inch in a mesh.
Bop is more popular than its bigger grades.

BopSm-- Size wise it comes after Bop. It contains both liquor and flavour. Actually more flavour. It is popular among household consumers.
For getting Bopsm, you require 12 holes per inch in a mesh.

BP-- Size wise its an ideal size, appearance eye pleasing, contains both strong liquor and nice aroma. Very popular among household consumers and high end hotels.
To get BP, you need 14 holes per inch in a mesh.

BPsm-- Smaller than BP, contains stronger liquor, popular among big hotels and households.
Here you require 18 holes per inch in a mesh.

OF-- Size is eye pleasing like BP and BPsm. Contains strong liquor. Popular with all hotels, restaurant, tea stalls etc and to some extent among domestic consumers.
For making OF grade, your mesh must have 22 holes per inch.

PD-- Pd is above PF and Dust and below OF- size wise. Popular with tea stalls, restaurant due to its strong and quick liquor. Generally PD gives nice coloured tea.
You require 26 holes per inch in your sorting mesh.

Dust-- The final and smallest size. It gives strongest colour and liquor. Very popular with tea stalls. But should be used with other grades. Otherwise, it resembles more like dirt.
to get this smallest sizes, you need to use 30 holes per inch mesh.

We call Bopsm, BP and Bpsm are premium grades and these are costlier than other primary grades.

Secondary grades are described with same name but with an 1 at the end. Like BP1, Bopsm1, Of1.
Secondary grades contains all characteristics of primary grades but in lesser quantity.
For example Bp1 will look similar to Bp but Bp1 will be somewhat brownish. It will contain less liquor, less aroma and also less bloom.
Similarly all secondary grades are similar sizes of theirs primary counter part but contain less qualities then the primaries.