The chemical pathways taken by tea over time are incredibly complex and are perhaps the most rewarding aspect of tea. Chinese describe teas as sleeping once they have been fixed. This metaphor extends to the first infusions and washing of tea leaves in which the tea is said to awaken. Tea undergoes primary, secondary, tertiary and more reactions over a period of thirty and more years. The aromas become flavors, and the flavors become textures. Eventually the best old puers lose all aroma and take on a dense texture upon which drops, or pearls of the tea liquor, will even bounce upon the surface-tension of the resulting infusion. But there is a more profound transformation by which tea becomes more psychoactive over time. As tastes within the first five and then ten years stimulate different areas of the tongue, mouth, throat and nose, the initial wake-fulness sensations in a tea begin to stimulate different locals in the head and brain. For teas a decade and older the well known stimulant effect of caffeine becomes a subtle and nuanced sensation. For some puers there are psychotropic elements created by the yeasts and other microbes living on the tea, but for other teas the biochemistry and psychoactive qualities are less straightforward proceeding from reactions within the tea leaf itself.
