In viticulture, the yield is a measure of the amount of grapes or wine that is produced per unit surface of vineyard, and is therefore a type of crop yield. Two different types of yield measures are commonly used, mass of grapes per vineyard surface, or volume of wine per vineyard surface.The yield is often seen as a quality factor, with lower yields associated with wines with more concentrated flavours, and the maximum allowed yield is therefore regulated for many wine appellations.