The ripening of the grapes is the crucial stage in the berry is formed, both to consume wine or fresh fruit. There are factors that affect their development: soil type, water availability and climate of the area.
Veraison begins with the ripening of the grapes, until then, both white grapes and inks are green. From this stage, the grapes evolve differently depending on whether you are white or inks: white grape start taking a yellow hue, while the ink develops a reddish color.
Grapes, except for other fruits such as apples or pears not mature after harvest, this is caused by the intervention of auxin, a group of plant hormones that act as plant growth regulators.
It is essential to note that each grape is independent of each other in the same cluster, so each fruit reaches maturity at different times.
During the ripening process, grapes undergoes several changes. First fattening the fruit, this is due to the accumulation of water occasionally burst reaches the skin if the year is rainy. An accumulation of sugars, particularly glucose and fructose, which mark the correct development of maturation also produced. The amount of sugar that is formed during this phase is strongly influenced by the light that receives the plant; many hours of sun, the greater the duration of photosynthesis and sugar production.
As aromatics, terpenes, one of the most important, are attached to sugar. This is released during fermentation and showing the typical aromas of each variety. Finally, the phenolic compounds undergo a behavior that depends on the variety of grape and the same tissue.
Physiological maturity begins when the grapes reached its maximum size and the highest concentration of sugars. At this point, starts decreasing grain size, the water and grape pasifica lost. From this moment, stop unwanted enólicamente synthesize compounds for winemaking. An increase in the concentration of the components of the pulp, especially sugars (due to dehydration of grapes) is recorded, and aromatic and phenolic compounds begin to degrade. However, it is preferable to start the process of making wine with a beginning of ripening.
The time of harvest is crucial to the quality of the future wine. When the grapes are picked green, without reaching the maturity, the wine is acidic, with marked notes and herbaceous aromas faults that characterize the different wines. In these cases, the grapes produce liquid with little color and astringent as the action of enzymes is scarce and wine not clarified well.
Conversely, when the grapes are overripe, lacking acidity, easily oxidized by the high pH and absence of aroma products are obtained. It is essential to determine the right time to harvest the grapes. One of the criteria that guide the technological maturity is based on the measurement of acids and sugars in the pulp, but does not take into account the state of maturity of the skin and seed. In warm areas, the process is faster than the other components of the grain, you will reach the technological maturity immature seed and skin. The result is herbal wines, acids and low color.