Influence of Water Stress on Grape Quality: The Example of Flavonoids

This article reviews the structural characteristics and biosynthetic pathways of grape flavonoids—flavan-3-ols (proanthocyanidins), flavonols, and anthocyanins—and examines how water stress conditions modulate their accumulation in the berry. It describes the variation in flavonoid composition across grape tissues, highlights the environmental triggers for their synthesis, and presents evidence that controlled water deficits can enhance or alter levels of pigments and tannins at harvest. The impact of these changes on grape composition is linked to organoleptic properties of wine, offering insights for viticultural practices that aim to adjust wine color stability, astringency, and overall quality.