In the 1970s, a style of processing called shou (or 'cooking') was developed to expedite the fermentation process. Shou processing involves the application of heat and moisture, as well as the inoculation of the tea leaves with beneficial bacteria. It takes about a year for harvested tea leaves to become 'ripened' or 'finished' pu-erh. Some 'ripened' pu-erhs are also aged for a flavor more similar to traditionally produced Sheng pu-erh. Shou Puerh is known for its robust, earthy flavor and aroma, dark, rich liquor and grounding Qi.