Veraison
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Vêraison is a French term, meaning..., but has been adopted into the English literature on viticulture .... Veraison signifies the change from berry growth to berry ripening in grapevines. Many changes occur at verasison. Grape berries follow a double sigmoid growth curve. The initial phase of berry growth is a result of cell divison and cell expansion. As berry growth of phase I slows this is termed the Lag phase. The lag phase is not a physiological growth stage, but an artificial designation between the two growth periods of grape berry development.
Degradation of Malic acid resulting in a decrease of berry titratable acidity. Grapes also possess as small amount of citric acid, but Tartaric acid is another dominant acid. tartrate accumulatews early in phase I of berry growth, while Malic acid accumulated at the end of phase berry growth Accumulation of hexose sugars (% sucrose % fructose) associated with the development of xylem cell dicontinuities. THe deposition of sugar into the berry depends on the level of leaf photsynthesis, the numer of competing sinks on the vine and sugar importation. Berry softening associated with decompartmentiatation of pericarp cells Herbaceous aromas are degrated. It unknown whethter the degradation of herbaceous aromas allows fruit aromas to be detected, or if fruity aromas develop later in berry ripening Change in colour of the berry. Presumably chlorophyll is broken down. In White cultivars carotenoids are formed, while in red cultivars anthocyanins and xanthophylls are formed. Signifies that seed development is complete, in that the seed is capable of germination. However, the seed continues to accumulate dry matter associated with... THe berry also begins its second phase of growth.
The trigger of veraison is unknown
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