What role do tannins play in red wines?

Tannins are essential compounds found in red wines that are primarily derived from the grape skins, seeds, and stems, as well as from the wood of barrels used during aging. Their contribution to the sensory profile of red wines is significant; they impart a distinct bitterness and astringency, which are crucial for the structure and mouthfeel of the wine. This astringency is what can make a wine taste dry, as tannins can bind with proteins in saliva and create that puckering sensation in the mouth.

In addition to adding to the flavor profile, tannins also play a role in the aging potential of red wines. Their presence helps to stabilize color and contribute to the overall complexity of the wine over time. As wines age, tannins can soften and integrate better, leading to a more harmonious and balanced wine.

While tannins do not enhance sweetness or provide acidity, they do contribute color to some extent, but their primary role in the context of the sensory experience is the bitterness and astringency. Thus, their characteristic contributions align closely with the option that highlights their role in providing bitterness and astringency.