The specialist terms used to describe the leaf sizes (or leaf grades) of the finished tea can be confusing for non-experts. Basically, teas are divided into leaf teas and small-leaf types. Today, because the CTC method dominates, small-leaf teas account for about 98% of global production. They have a more intensive aroma than the same leaf teas. You’ll always find the word "broken", or "B" for short, in their names.
The leaf size (leaf grade) says nothing about the quality of a harvest as due to the processing method the different leaf sizes may all come from the same harvest. However, the leaf size determines the later use of the tea. Large leaf teas produce on average two to three times fewer cups than the smallest sizes (fannings and dust) which produce a strong and aromatic brew. Therefore, only the latter are usually being used for tea bag blends.
Leaf grades only describe the size of the leaves, not their quality. From the many leaf grade descriptions used for tea, here are the most important ones:
