Phenolic content in wine - quercetin. Like other flavonoids, the concentration of flavonols in the grape berries increases as they are exposed to sunlight. Some viticulturalists will use measurement of flavonols such as quercetin as an indication of a vineyard's sun exposure and the effectiveness of canopy management techniques. Anthocyanins are phenolic compounds found throughout the plant kingdom, being frequently responsible for the blue to red colors found in flowers, fruits and leaves. In wine grapes, they develop during the stage of "veraison" when the skin of red wine grapes changes color from green to red to black. As the sugars in the grape
Wine Grapes to a connection between the Italian variety Primitivo and the Croatian wine grape Crljenak Kaštelanski. After years of research and DNA testing of vines from vineyards across the globe, a single 90-year-old grape vine from the garden of an elderly lady in Split, Croatia provided the evidence to show that Zinfandel was originally a Croatian grape known as "Tribidrag" that had been cultivated in Croatia since the 15th century. Other findings reported in "Wine Grapes" include the discovery of several species of Malvasia grapes growing in central and southern Italy are actually the Spanish wine grape Tempranillo and that Cabernet