Consumer demand for intensely coloured wines necessitates the systematic testing of pigment extraction in Sangiovese, a cultivar poor in easily extractable anthocyanins. Pre-fermentation (absent, cold soak pre-fermentation at 5 °C, cryomaceration by liquid N2 addition), temperature (20 or 30 °C), and saignée were compared during vinification (800 kg). Concentrations of anthocyanins, non-anthocyanic flavonoids and SO2-resistant pigments were recorded daily. A semiparametric Bayesian model permitted the kinetic description and the comparison of sigmoidal- and exponential-like curves. In total anthocyanins, saignée at 30 °C yielded a significant gain, later lost at drawing off; cryomaceration had little effect and cold soak no effect at drawing off. Non-anthocyanic flavonoids increased steadily with saignée and at 30 °C. SO2-resistant pigments were higher, particularly for the higher temperature/saignée combination. Using daily recordings, the model indicates turning points for concentration rise or fall, thus allowing a precise and detailed comparison of the vinification methods.


Biostatistics | Viticulture and Oenology