Tea is sorted into various grades. These grades are not standardised worldwide and may vary according to origin.
A tea's grade does not necessarily indicate flavour or quality. They are rather determined by many different factors including: the country of origin, the variety of the tea, the garden or estate, the elevation, the particular flush (picking) and the manufacturing after harvesting.
Most black teas are graded and sold according to leaf or particle size. The harvesting and manufacturing of tea has a great impact on the finished size of the leaf, thus the tea grade. There are two main methods of producing black tea. The traditional Orthodox method requires hand plucking of the top two leaves and the bud and may yield all of the possible leaf sizes and grades.
The CTC (crush, tear, curl) method has been gaining in popularity because of its efficiency and convenience. CTC processed teas may be either hand plucked or harvested by machinery. When machine harvested, the CTC process gathers the traditional top two leaves and bud as well as other leaves on the tea bush. The leaves are then processed through the CTC machine, have a palletised appearance and are always broken sizes.

There are four main grades for black tea:

Orange Pekoe (OP)
pronounced 'Peck-oh', is a whole leaf tea showing no tip and will not pass through a certain designated sieve size. These leaves are usually of uniform size and rolled lengthways.
Tippy Golden Flowery Orange Pekoe (TGFOP) is the top grade. During harvesting the top two leaves and bud are plucked by hand. The bud is actually the immature leaf tip which is not yet fully opened. When harvested during the slow growth periods these young buds have a golden tip hence the grade 'Flowery'. When these tips are in abundance the terms 'Tippy and Golden' are also attached. Occasionally the number '1' or '2' may be placed at the end of the letters to designate better grades among similar teas. Similarly the letter 'F' may appear before the TGFOP to designate a 'finer' grade and the letters 'SF' designates a grade of 'super fine.' Thus a tea graded as 'SFTGFOP1' is a Super Fine Tippy Golden Flowery Orange Pekoe - grade 1.

Broken Orange Pekoe (BOP)
is the next grade below Orange Pekoe which designates a broken leaf. Tippy, golden, and flowery or a combination of these terms may also be applied to this size of leaf. Thus a grade of 'TGBOP' is a Tippy Golden Broken Orange Pekoe tea.

Fanning (F)
is smaller than BOP. This is a broken leaf about the size of a pin head.

Dust (D)
is the lowest grade of tea available if produced by CTC method of manufacturing and Dust if produced by the Orthodox Method. This size is literally the smallest broken pieces left after siftings, sometimes called the 'sweepings' and only used for tea bags.

Black Tea

These grading terms are usually applied to black teas from India, Sri Lanka, Java, Sumatra, Africa, a few Chinese teas and to some other black teas. It is important to keep in mind with this grading system that whole leaf size teas command higher prices and have greater visual appeal. However the broken sizes can possess excellent flavour and aroma. Plus the smaller size tea leaves steep quicker releasing flavour faster.

The grading of green and oolong teas is a little more subtle and less structured than that of black teas. Unlike black teas the grading of green tea has a definite relationship with the quality and flavour of the tea. Green and oolong teas are priced according to the variety of the tea, the province and estate where grown and the flush or picking.

Green Tea