Phenolic budget in red winemaking: Influence of maceration temperature and time

This study investigates the effects of maceration temperature (24 or 29 °C) and duration (12, 18, or 24 days) on phenolic compounds during 'Nebbiolo' wine-like extraction and lab-scale winemaking. In wine-like maceration, anthocyanins quickly peaked and then decreased, with temperature alone showing limited influence on extraction or degradation. In lab-scale fermentations, the rapid anthocyanin extraction at 29 °C was followed by higher degradation, driven by fermentative enzymatic activities and evidenced by increased skin softening at higher temperatures. Longer macerations led to less wine anthocyanins. Tri-substituted anthocyanins were better preserved at 24 °C. Tannin content and structure were minimally affected. Phenolic analyses of grapes, wine, pomace, and lees revealed the extracted, unextracted, resorbed, and degraded phenolic fractions. Reduced anthocyanins in pomace at higher temperatures or extended maceration indicated enhanced extraction and subsequent degradation. The study introduces a "phenolic budget" concept, highlighting the interplay of maceration parameters shaping 'Nebbiolo' wine phenolics.