Harvest (wine) of wine, winemakers would use the sugar and acid levels of the grape as a guide in determining ripeness. Early winemakers tasted the grapes to gauge ripeness. Modern winemakers use a refractometer to measure high sugar levels and °Brix or titration tests (using an indicator such as phenolphthalein) to determine the titratable acidity within the grape. In recent times there has been more of an emphasis on the "physiological" ripeness of the grape, usually in the form of tannins and other phenolics. Currently, tasting is the only way to measure tannin ripeness, which can take experience and skill to do
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