First is clarity—smell the Tea. Regardless of whether the Pu'er tea is raw or ripe, new or old, good or bad, loose Leaf or compressed, or its price, the first step is to smell it. After Pu'er tea has undergone aging and fermentation, it should develop a mature aroma. However, there should be no musty odor. A musty smell indicates that the storage area was damp or excessively humid, lacking ventilation. The mature aroma should dissipate with the heat when the tea is brewed, while a musty smell is due to the tea having spoiled and become moldy from being damp both inside and out.
Second is purity—judge by its color. Before brewing, check if the tea has a clear scent (no strange or foul odors), then Brew it. When Pu'er tea is stored under normal conditions, even after 30, 50, or even 100 years, the color of the tea liquor will not turn black or develop odd flavors.
Third is proper storage—Pu'er should be stored in a clean, well-ventilated environment free of other odors.
Fourth, tea readily absorbs nearby scents. The aroma of the brewed tea can indicate the storage conditions and the duration of oxidation. The Pu'er tea market is not yet fully developed, and few tea merchants have the ability to accurately appraise Pu'er tea. Many tea shops cannot distinguish the true quality of the tea. Motivated by profit, some pass off teas as old brands or print-grade teas. There are also instances where so-called vintage Pu'ers, purportedly aged 20, 30, or even 50 to 60 years, appear more frequently. Some tea merchants store their teas in dark, high-humidity environments to accelerate aging, artificially moistening them, which often leads to mold and spoilage. After the tea rapidly deteriorates, they dry the cakes, obtaining what appears to be aged Pu'er known as “wet-storage tea” within a short period.
If it smells free of mustiness and the brewed tea liquor is reddish-brown without any strange odors, you can enjoy it with peace of mind. If it looks like it might be moldy, it could be a misinterpretation. Because Pu'er tea's buds and leaves are very plump and covered in fine down, the processed tea is densely covered in white down, which can indeed look somewhat like mold at first glance.