Tannin is a crucial component that all plants produce and build, not just grapes.
Answer: True.Tannin belongs to a class of complex compounds called phenols that all plants use for protection, preservation, and defense. Since Neolithic times, plant tannins have been used to prevent the spoilage of animal skins—when "tanning" hides into leather, for instance. As for grapes, tannin comes primarily from skins and seeds (although stems, too, have tannin, but stems aren't typically used in winemaking). Different varieties of grapes are predisposed to have different amounts of tannin. Cabernet sauvignon, for example, has more tannin than pinot noir. The tannin structure in wine contributes to the wine's overall ageability (which is why you can buy those Bordeaux from 50 years ago, and many still taste delicious).