Phenolic content in wine the ellagic and gallic acid found in the wood. In the vineyards, there is also a growing distinction being made between "ripe" and "unripe" tannins present in the grape. This "physiological ripeness", which is roughly determined by tasting the grapes off the vines, is being used along with sugar levels as a determination of when to harvest. The idea is that "riper" tannins will taste softer but still impart some of the texture components found favorable in wine. In winemaking, the amount of the time that the must spends in contact with the grape skins, stems and seeds will influence
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)