The skin of the grape accounts for 5 to 20% of the total weight of a grape depending on the variety. When grape skin ripens, it contains the majority of the aromatic substances and tannin. These factors become important in winemaking for methods including color extraction or aroma dissolution. Although the skin contains the majority of the tannin, small percentages can be found throughout the grape and during all of its developmental stages. However, the tannin's most important role is during the grape's ripening stage as its function is to formulate color and body shape.