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
History of the wine press Terentius Varro, Pliny the Elder and others described wooden wine presses that utilized large beams, capstans and windlasses to exert pressure on the pomace. The wines produced by these presses were usually darker, with more color extracted from the skins but could also be more harsh with bitter tannins also extracted. That style of wine press would eventually evolve into the basket press used in the Middle Ages by wine estates of the nobility and Catholic Church leading to the modern tank batch and continuous presses used in wineries today. The exact origins of winemaking (and, thus, of pressing grapes)