Modulation of colour extraction in red wines by a combination of fermentation parameters: a multi-variety comparative study.

this study investigates "how much" we can modulate the final wine color through process engineering. Providing winemakers advice to implement new technological itineraries, particularly in the case of interspecific hybrid study, constitutes a significant improvement to their adoption by the wine sector. Since our study has demonstrated the reciprocal impacts of polyphenol extraction and fermentation behaviour, fermentation parameters could have an impact on polyphenol extraction and be an impacting lead to manage key quality markers through macroscopic parameters optimization. Using a Doehlert experimental design and Response Surface Methodology (RSM), we explore the optimization of color (CIELab coordinates, optical density at 420, 520 and 620 nm) and polyphenolic extraction (TPI, non-bleachable pigments NBP) for six red varieties (3 hybrids and 3 Vitis vinifera). The goal is to determine if universal winemaking rules can be established or if the "matrix effect" (cultivar-specific composition) overrides technological intervention. We focus on three critical fermentation levers: Temperature (21-27°C): To modulate diffusion and solubility. Nitrogen supplementation (0-100 mg/L): To evaluate its indirect impact on extraction via yeast activity. Pectolytic enzymes (0-3 g/hL): To act directly on the cell wall "barrier." By crossing these parameters across contrasting varieties (including G14 and Artaban), this study provides a decision-making framework for winemakers, particularly those integrating new disease-resistant hybrids into their portfolios.