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
Mexican wine by clergy. The Santo Tomás Mission, founded in Baja California by Jesuit priests in 1791, reactivated larger scale production of wine in Mexico. In 1843, Dominican priests began growing grapes at the nearby Nuestra Señora de Guadalupe del Norte mission, located in what is now called Valle de Guadalupe. This valley is one of the few in the world, along with others such as the Napa Valley and the Rhone Valley, in which premium wine grapes can be grown. In the 1850s, as part of Mexico’s Reform War, many of the Church’s land holdings were taken by the state. Most