Let's say a grape variety normally takes 120 days to ripen. In an especially hot year, it may ripen after only 110 days; in a cooler year, after 130 days. Viticulturists generally do want a long growing seasons. Long ripening allows components in the grape other that sugar - tannins, for example - to reach greater physiological maturity. Fully developed grapes, of course, hold more promise for fully developed flavors and aromas. Historically, perfectly ripe (but not overripe) grapes with long "hang times" have often produced superior wines that age gracefully.