Puerh is a fermented tea. There is a little confusion about what fermented tea actually is due to misunderstandings in tea producing nations and in the West. Some tea producing regions call all dark tea fermented tea simply because the dark leaves look as though they have gone through fermentation. However, we know that Black tea leaves are not processed through fermentation, their processing relies on oxidation. Although, because Puerh is fermented and aged, meaning that it sits for long periods of time exposed to moisture and air, the tea leaves naturally oxidize slowly.