Astringency is a tactile sensation, not a taste. As hunter-gatherers, our forebears needed instantaneous, hard-wired sensory clues to phenolic content—astringency and its taste analog, bitterness—to distinguish nourishment from poison, determine ripeness, and so forth. Sensory stimuli from all five senses are directed to the thalamus in the midbrain, where snap decisions tell us whether to swallow or spit.
