Shu Pu'er

Shu pu'er tea is tea that has been post-fermented, meaning that after the oxidation process is over and the tea has lost all of its green color, it is then deliberately fermented to slightly break down and develop a new flavor.

Teas from Pu'er are prized because they change dramatically with aging, developing a smooth, sweet, dark flavor as the tea ages and darkens. For a long time in the history of tea, there was only one way to accomplish this flavor:

Put the tea away, and wait. For several years. Decades, perhaps.

As Chinese tea became a global market, the demand for the smooth sweetness of aged Pu'er needed meeting somehow; short of time travel, how do you make an object age faster? The answer came in the form of wò duī (渥堆), or "wet piling", where producers make piles of tea, get the piles wet, and let them ferment, carefully turning and monitoring the piles to ensure the correct microbial activity. This method speeds the wait time, reducing it to around 45 days, instead of several years.

The liquor that comes off of these teas is dark brown or black, almost opaque until held up to the light, where they should become translucent to transparent.

These teas can generally handle boiling water and many, many steeps.