Puer tea has a history of more than 2000 years and originates in the Yunnan province in southwest China. The production process for Puer is different from other types of tea. The age of the tea, how old the tea trees are, the origin of the tea leaves and the processing methods required mean that there will be large variations in the finished tea. Both shu and sheng puer are made from sun-dried green tea. There are two different types of puer: sheng pu (raw or green type) and shu puer (the mature or black type). Sheng Puer undergoes a slow oxidation as the flavors can change over time while shu puer undergoes an accelerated oxidation and fermentation which makes them a more or less final product. Puer can be pressed into cakes or even sold in bulk.