Tea blending is the blending of different teas together 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. The aim of blending is to create a well-balanced flavour using different origins and characters. This also allows for variations in tea leaf quality and differences from season to season to be smoothed 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.