In the tea industry, tea leaf grading is the process of evaluating products based on the quality and condition of the tea leaves themselves. The highest grades are referred to as "orange pekoe", and the lowest as "fannings" or "dust".
Pekoe tea grades are classified into various qualities, each determined by how many of the adjacent young leaves (two, one, or none) were picked along with the leaf buds. Top-quality pekoe grades consist of only the leaf buds, which are picked using the balls of the fingertips. Fingernails and mechanical tools are not used to avoid bruising.
When crushed to make bagged teas, the tea is referred to as "broken", as in "broken orange pekoe" (BOP). These lower grades include fannings and dust, which are tiny remnants created in the sorting and crushing processes.
Orange pekoe is referred to as "OP". The grading scheme also contains categories higher than OP, which are determined primarily by leaf wholeness and size.
Broken, fannings and dust orthodox teas have slightly different grades. CTC teas, which consist of leaves mechanically rendered to uniform fannings, have yet another grading system.
Orange pekoe (/pɛk.oʊ/ or /piː.koʊ/), also spelled pecco, or OP is a term used in the Western tea trade to describe a particular genre of black teas (orange pekoe grading). Despite a purported Chinese origin, these grading terms are typically used for teas from Sri Lanka, India and countries other than China; they are not generally known within Chinese-speaking countries. The grading system is based upon the size of processed and dried black tea leaves.
The tea industry uses the term orange pekoe to describe a basic, medium-grade black tea consisting of many whole tea leaves of a specific size; however, it is popular in some regions (such as North America) to use the term as a description of any generic black tea (though it is often described to the consumer as a specific variety of black tea). Within this system, the teas that receive the highest grades are obtained from new flushes (pickings). This includes the terminal leaf bud along with a few of the youngest leaves. Grading is based on the 'size' of the individual leaves and flushes, which is determined by their ability to fall through the screens of special meshes ranging from 8–30 mesh. This also determines the 'wholeness', or level of breakage, of each leaf, which is also part of the grading system. Although these are not the only factors used to determine quality, the size and wholeness of the leaves will have the greatest influence on the taste, clarity, and brewing time of the tea.