Pu-erh tea is fully fermented and aged tea, normally compressed into a "cake". It is stored for many years and even decades in cool, dry cellars which mellows the flavour and adds smoothness and complexity. Sold like vintage wine, some Pu-erhs are very rare and expensive. Pu-ehr has rich, smooth and earthy tastes. Pu-ehr can be re-infused many times over, the flavour changing subtly with each infusion.