Not only Pu-erh tea, but also for all kinds of tea, the depth of taste and flavor defines the quality. The depth of taste is also called as "after taste" in English. In Chinese it is called Hou Yun（喉韵）. “Hou” means throat and “Yun” means lasting lingering charm. Hou Yun means the taste felt in our throat and lingered. In English, it is difficult to find an appropriate term to describe this feeling. Perhaps the closest term is “aftertaste”, “depth of taste” or “long finishing”.
Hou Yun gives depth to the taste. In other word, it builds up the taste in three-dimensional way. The intensity of Hou Yun is caused by minerals. On the other hand, flavor defines the character or individuality of tea. We cannot compare the superiority of different flavors. Flavor is like the color of a photograph. A different brand of camera or lens gives different color. However color does not define the quality of lens or camera. We usually appreciate depth and blur effect that creates a three dimensional visual impact to the photograph. Similarly, Hou Yun means the depth of taste and the feeling that continuously lingers in our throat. This is what defines the quality of tea.
Hou Yun is an essential factor to define not only the quality of tea, but also the quality of food, including wine, vegetables, fruits, beer and juices. Let’s compare two cup of fruit juices, one taste delicious and the other doesn't. What do you think the difference is? Is it the sweetness? Does low quality fruit juice get better if sugar is added? Or is it because of flavor? Does low quality fruit juice get better if flavor is added? As the matter of fact, both sweetness and flavor is not the essential factor to define the quality that gives us the satisfaction. For food and beverage, good quality product gives depth in taste. It is just like the Hou Yun that makes the taste and flavor of food felt in 3 dimensional.
The Hon Yun defines the quality of Pu-erh tea, thus the price of tea is in proportion to the intensity of Hou Yun. Under such circumstances, one must know how to appreciate Hou Yun. Unfortunately very few people know how to appreciate Hou Yun. If one does not know how to appreciate Hou Yun, there is no choice but to depend on the “brand”. This is the reason why many people look for the tea that is produced from famous factories. In fact, big factories can hardly produces high quality Pu-erh since they need to blend teas in order to get consistent supply for committed quantity. The intensity of Hou Yun is decided by the quality of material existing in the tea leaves. The processing of tea does not affect it. If the harvested tealeaves is good in quality, Hou Yun must be pretty good no matter how terrible the tea is processed. On the other hand, the intensity of Hou Yun will never be improved no matter how well the tea was processed if the raw material is not of good quality.
There is only one exceptional case that the Hou Yun of ripe Pu-erh will change in relative to certain kind of mold fermentation.