Pu-erh tea

„Depending on the desired product and speed, from quickest and tightest to slowest and loosest, pressing can be done by a large heavy stone, carved into the shape of a short cylinder with a handle, simply weighs a bag of tea down onto a wooden board. The tension from the bag and the weight of the stone together give the tea its rounded and sometimes non-uniformed edge. Due to the manual labor involved, this method of pressing is often referred to as: "hand" or "stone-pressing", and is how many artisanal pu'er bǐng are still manufactured.“

„Yunnan Provincial Government has stipulated that for tea to qualify as Pu er it must be:

i) of the Broad Leaf variety (Sinensis Assamica)
ii) grown in the Lancang (Mekong) River region
iii) sun dried. The third point is important as there is much tea grown in the Lancang River area that is not sun dried.

There are also increasing amounts of Small Leaf Variety (Xiao Ye Zhong /小叶种) being grown in the Lancang River area.“