Definition: What differentiates red wine from white is first, the skin color of the grape, and second, the amount of time the grape juice has with its skins. After picking, red grapes are put into tanks or barrels where they soak with their skins, absorbing pigments and other aspects of the grape skin, such as tannins. This is how red wine gets its red color. The exact color, which can range from light red to almost purple, depends on both the color of the particular grape skin and the amount of time spent on the skins. Remember, the inside of almost all grapes is a light, golden color – it's the skins that have the pigment.
The left side navigation menu is roughly organized from lighter-bodied to fuller-bodied, lower tannins to higher tannins and light color to deeper color – but note that this is not an "always" list, just a general guideline.