The biological cycle of the grape cluster

The reproductive cycle of the grape extends from February to September. Climate, day-to-day weather, humidity, soil and irrigation affect berry formation, requiring observation and experience when a season brings excessive or insufficient rain.

One season's Verdiso vines showed particularly successful fruit set despite Veneto's abrupt alternation between snowfall, hail and drought. Flowering normally lasts 9–21 days, with sunlight and temperature playing decisive roles. Pollination may be aided by wind and insects such as bees.

During fruit set, fertilised flowers become berries; temperature, climate and soil nutrients shape their growth, and the developing bunches rotate into a vertical position. At veraison, berries change from green to the colour associated with their variety while the pulp expands. Ripening is complete as berries gain weight and volume, accumulate fructose and glucose, lose acidity, increase in pH, develop elastic texture and build aromatic compounds. At that point, the bunch is ready for harvest and vinification.