The grape bunch, the emblematic fruit of viticultural labour, is far more than a mere cluster of berries. It is the heart of winemaking, directly influencing the quality, aromas, and structure of the future wine. Its formation and development, from flowering to full ripeness, are crucial stages for the winegrower.

Anatomy of a singular bunch

The bunch is the reproductive organ of the vine, bearing the berries that contain the precious juice. It consists of a peduncle connecting it to the shoot, and a rachis (stem), the branched central axis from which pedicels attach to each berry. Tendrils, although often reduced, can sometimes develop into small secondary clusters, giving rise to what are known as "winged bunches". This characteristic is more common in cultivated vines than in their wild counterparts, as described in the Ampélographie by Viala and Vermorel (1901).

Key stages of its development

The bunch's cycle begins with budburst, followed by the growth of the inflorescence. After flowering, when each flower can be fertilised to produce a berry, comes fruit set, the period during which the tiny berries form. This is a delicate stage when phenomena such as coulure or downy mildew on bunches can compromise the crop. Bunch closure marks the stage when the berries swell to touch one another, making the centre of the cluster more vulnerable to disease if the canopy is too dense. At this point, canopy management techniques such as leaf stripping are essential to ensure good aeration and optimal sun exposure.

The essential transformation of ripening

The most spectacular phase is undoubtedly veraison, when the grape berries change colour (from green to golden-yellow for white grape varieties, and to reddish-black for red grape varieties). This process marks the start of the accumulation of sugars, anthocyanins (for colour), and tannins in the skins and seeds. It is also during this period that acidity drops and the characteristic varietal aromas develop. The final quality of the wine depends largely on the optimal ripening of the berries.

The decisive moment of harvest

Choosing the harvest date is a crucial decision, based on the balance between sugar levels, acidity, and the phenolic ripeness of the berries. This moment of celebration and hard work, as described in La Gironde à vol d'oiseau, sees pickers harvesting the precious bunches, which are then transported to the winery for vinification. Great vigilance is required to ensure that the picked bunches are healthy and that their condition does not compromise the quality of the must.

Château Cazebonne is committed to cultivating vines with respect for their environment, replanting forgotten Bordeaux grape varieties and crafting wines that reflect the richness of our terroir. This meticulous work is made possible thanks to the support of discerning wine lovers. To find out more about our approach, you can download our book "Bordeaux, une histoire de cépages" and test your knowledge with our wine quizzes. We also invite you to discover our wines online, the fruit of our passion and our commitment to a rediscovered viticultural heritage.