What factors can influence the color of red wine?

The color of red wine is significantly influenced by grape skin contact and the aging process. The presence of grape skins during fermentation is crucial because it is the skins that impart color to the wine. Red grape varieties contain anthocyanins, the pigments responsible for the red hues. The longer the grape skins remain in contact with the juice during fermentation, the deeper and more intense the color of the wine will be.

Additionally, the aging process can impact color. As red wines age, chemical reactions occur that can lead to color changes, often causing a shift from a vibrant purple or red to a more brick or tawny hue. This can be attributed to oxidation and the development of complex compounds in the wine, which alters its appearance over time.

Alternative influences such as climate, soil composition, oak aging, sugar content, fermentation temperature, and grape variety do play roles in winemaking and can affect wine in a broader sense. However, for the specific question regarding color specifically, grape skin contact and the aging process are the most direct and critical factors.