Veraison
Encyclopedia
Véraison is a viticulture
(grape-growing) term meaning "the onset of ripening". It is originally French
, but has been adopted into English
use. The official definition of veraison is "change of color of the grape berries." Veraison represents the transition from berry growth to berry ripening, and many changes in berry
development occur at veraison.
. The initial phase of berry growth is a result of cell division
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.
Post-veraision, fruit acidity decreases due to degradation of Malic acid
. The degradation of malic acid during ripening makes Tartaric acid the predominant acid; grape berries also possess a small amount of citric acid. Tartaric acid accumulates early in phase I of berry growth, while malic acid accumulates at the end of phase I berry growth.
At the same time as acidity decreases, hexose sugars are accumulated. The accumulation of hexose sugars (glucose
, fructose
) is associated with the development of xylem cell discontinuities. These discontinuities reduce the volume of water entering the berry relative to the volume of sugar, resulting in an increase in sugar concentration. Physiologically the sugar concentration can increase to around 25 percent via sugar imporation. Further increases in sugar concentration are due to dehydration of the fruit. The deposition of sugar
into the berry depends on the level of leaf photosynthesis
, the number of competing sinks on the vine and sugar importation.
As ripening continues, the fruit becomes attractive to animals. The fruit changes from acidic to sweet with fruity aromas. As ripening occurs, herbaceous aromas (e.g. methoxypyrazines) are degraded. It is unknown whether the degradation of herbaceous aromas allows fruit aromas to be detected, or if fruity aromas develop later in berry ripening.
The berry also changes in color. Presumably chlorophyll
is broken down. In white cultivars carotenoids are formed, while in red cultivars anthocyanin
s and xanthophyll
s are formed.
The trigger of veraison is unknown, but veraison signifies the seed reaching maturity. However, seed maturity is unlikely to cause as seedless berries also proceed through veraison.
.
Viticulture
Viticulture is the science, production and study of grapes which deals with the series of events that occur in the vineyard. When the grapes are used for winemaking, it is also known as viniculture...
(grape-growing) term meaning "the onset of ripening". It is originally French
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...
, but has been adopted into English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
use. The official definition of veraison is "change of color of the grape berries." Veraison represents the transition from berry growth to berry ripening, and many changes in berry
Berry
The botanical definition of a berry is a fleshy fruit produced from a single ovary. Grapes are an example. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. They may have one or more carpels with a thin covering and fleshy interiors....
development occur at veraison.
Process
Grape berries follow a double sigmoid growth curveGrowth curve
A growth curve is an empirical model of the evolution of a quantity over time. Growth curves are widely used in biology for quantities such as population size, body height or biomass...
. The initial phase of berry growth is a result of cell division
Cell division
Cell division is the process by which a parent cell divides into two or more daughter cells . Cell division is usually a small segment of a larger cell cycle. This type of cell division in eukaryotes is known as mitosis, and leaves the daughter cell capable of dividing again. The corresponding sort...
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.
Post-veraision, fruit acidity decreases due to degradation of Malic acid
Malic acid
Malic acid is an organic compound with the formula HO2CCH2CHOHCO2H. It is a dicarboxylic acid which is made by all living organisms, contributes to the pleasantly sour taste of fruits, and is used as a food additive. Malic acid has two stereoisomeric forms , though only the L-isomer exists...
. The degradation of malic acid during ripening makes Tartaric acid the predominant acid; grape berries also possess a small amount of citric acid. Tartaric acid accumulates early in phase I of berry growth, while malic acid accumulates at the end of phase I berry growth.
At the same time as acidity decreases, hexose sugars are accumulated. The accumulation of hexose sugars (glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
, fructose
Fructose
Fructose, or fruit sugar, is a simple monosaccharide found in many plants. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed directly into the bloodstream during digestion. Fructose was discovered by French chemist Augustin-Pierre Dubrunfaut in 1847...
) is associated with the development of xylem cell discontinuities. These discontinuities reduce the volume of water entering the berry relative to the volume of sugar, resulting in an increase in sugar concentration. Physiologically the sugar concentration can increase to around 25 percent via sugar imporation. Further increases in sugar concentration are due to dehydration of the fruit. The deposition of sugar
Sugar
Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...
into the berry depends on the level of leaf photosynthesis
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...
, the number of competing sinks on the vine and sugar importation.
As ripening continues, the fruit becomes attractive to animals. The fruit changes from acidic to sweet with fruity aromas. As ripening occurs, herbaceous aromas (e.g. methoxypyrazines) are degraded. It is unknown whether the degradation of herbaceous aromas allows fruit aromas to be detected, or if fruity aromas develop later in berry ripening.
The berry also changes in color. Presumably chlorophyll
Chlorophyll
Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
is broken down. In white cultivars carotenoids are formed, while in red cultivars anthocyanin
Anthocyanin
Anthocyanins are water-soluble vacuolar pigments that may appear red, purple, or blue according to pH...
s and xanthophyll
Xanthophyll
Xanthophylls are yellow pigments that form one of two major divisions of the carotenoid group. The name is from Greek xanthos + phyllon , due to their formation of the yellow band seen in early chromatography of leaf pigments...
s are formed.
The trigger of veraison is unknown, but veraison signifies the seed reaching maturity. However, seed maturity is unlikely to cause as seedless berries also proceed through veraison.
Other uses
Fête de la Véraison is a medieval festival held in the famous winemaking village of Châteauneuf-du-PapeChâteauneuf-du-Pape
Châteauneuf-du-Pape is a commune in the Vaucluse department in the Provence-Alpes-Côte d'Azur region in southeastern France.-History:Châteauneuf-du-Pape is firmly entwined with papal history. In 1308, Pope Clement V, former Archbishop of Bordeaux, relocated the papacy to the city of Avignon...
.