Tea blending describes the process of blending different teas to produce a final product. This occurs chiefly with black tea that is blended to make most tea bags but can also occur with such teas as Pu-erh, where leaves are blended from different regions before being compressed. Blending aims to create a well-balanced flavour using different origins and characters. This also ensures that variation in quality from season to season can be ironed out. The one golden rule of blending is this: Every blend must taste the same as the previous one, so a consumer will not be able to detect a difference in flavour from one purchase to the next.

Originally from The Tea Wiki page Tea Blending; Edited