Ahh yes, wine. Glorious glorious wine. There's nothing like enjoying the subtle nuances of the Napa Valley, the bits of earthiness elevated by the notes of apple breath, all unifying in harmony in your two buck chuck as you delicately swirl it around in your Solo cup (hey, I'm not judging, that stuff is good).
They were even used to dry animal hides into leather since prehistoric times. The process of drying produces a darkening color change to the hides, and the process of "tanning" leather has since given the compound it's name.
But for most of us, tannins are associated with their sensory impact in foods and beverages.
The sensation of dryness you experience as the taster comes from the compound's phenolic shape: tannins consists of 3-5 rings that are just the right size to separate protein molecules.
When they hit the palate, they bond to proteins in saliva, and prevent them from doing their normal duty of keeping your mouth lubed up to make it easier to swallow your food.
They leave the mouth feeling dry, and are found in red wines, certain teas, coffee, persimmons, pomegranates, berries, dark chocolate, grapes, and green bananas. They are nature's defense (or attempt at it) to keep animals from eating underripe fruit and plants, and have antibacterial and anti-fungal properties.
While bitter and astringent, if balanced appropriately, tannins contribute to exciting sensory and flavor experiences in our dining experiences. Let's drink to that.