Popular energy booster.

Pu er is unlike any other tea – in its production, effect, smell and of course taste. It has a very 'earthy' flavour which some love immediately and others warm to (quickly) after a mild but intriguing initial shock. Despite low levels of caffeine many people feel enlivened by it to the point that sleep is quite impossible even hours after drinking pu er; remarkably, others find it calms them down such that sleep comes fast and easy.