There are a countless number of red grape varieties in the world, some able to make wine, others best suited for Welch's grape juice. Right now, the world wine market focuses on about 40 to 50 different red wine grape varieties. What differentiates red wine from white is first, the skin colour 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 colour. The exact colour, which can range from light red to almost purple, depends on both the colour 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 colour – it's the skins that have the pigment.