Pu-erh comes from Yunnan, a Chinese province nestled against the borders of Myanmar, Laos, and Vietnam. It’s a fermented tea that falls into three categories: raw, cooked (also called ripe), and aged. Raw pu-erh has a lot in common with green tea. Cooked pu-erh, a more modern innovation that seeks to emulate aging through a “piling” process, tastes more like a black tea. When making pu-erh, producers treat leaves to encourage fermentation that builds next-level subtlety. This is chiefly the domain of the third category: aged.
Like wine or cheese, pu-erh can be aged for years, even decades. Time brings darker colors and deeper nuance. There are tea drinkers who approach aged pu-erh like wine collectors approach vintages of Bordeaux.