Phenolic compounds appear as the grape changes colour,substituting the chlorophyll. They are of great oenological importance and play a key role in determining the quality of the wine. Along with their nutritional and pharmacological properties they also account for characteristics like colour, aroma, taste and astringency (Bartolomé, Núñez, Monagas, & Gomez-Cordovés, 2004;Harborne & Baxter, 1999). Their antioxidant properties also have positive effects on a wine’s stability (Cheynier, 2001;Waterhouse, 2002). The total content of polyphenols is also an indication as to whether the wine can be aged.