veraison, word used in viticulture for that intermediate stage of grape berry development which marks the beginning of ripening. It is derived from the French term véraison. At the beginning of veraison, the berries are hard and green, and about half their final size. During veraison, the berries change skin colour and soften, sugars and volume increase, and acidity decreases. The colour of the grape before veraison is due to green chlorophyll, and at veraison berry skin changes colour to red-black (see anthocyanins) or yellow-green (see carotenoids), depending on the variety.