Many people believe that it is because red wine is produced from red (black) grapes. But what few people know is that almost all grapes have colourless juice; the reason a wine has a colour is due to letting the skin of the grape soaks in the grape juice until the red colour appears, depending of the presence of around 50 different red grape varieties.
The skins are in contact with the grape’s juice during the fermentation process, allowing the dispersal of both colour and tannins. These tannins also impart colour. Tannins have a mouth-drying quality that causes the wine to feel firm in your mouth. When a red wine is young, this firmness can be quite intense. Over time, the qualities of the tannin will mellow and blend harmoniously with the other characteristics of the wine. This is one of the main reasons that red wines usually age better than whites.