Pu Erh teas are teas that undergo an additional fermentation stage, after the other stages required to produce black, green or even white teas. They are also the only type of tea that can get better with age. They have long been appreciated both for their distinct flavours, with unique notes of undergrowth, and for their properties so useful to lovers of gastronomy. They are divided into "sheng", obtained from unoxidised teas, and "shu". The best qualities are best prepared with the "gong fu cha" method, in multiple infusions, revealing the range of aromatic nuances of the tea.