Influence of Tannin Concentration, Storage Temperature, and Time on Chemical and Sensory Properties of Cabernet Sauvignon and Merlot Wines

Storage conditions that may influence the chemical and sensory properties of young bottled Cabernet Sauvignon and Merlot wines were studied. Low and high tannin wines (≤400 mg/L and ≥800 mg/L catechin equivalents, respectively) stored at 23°C for 0 day (baseline) and at either 27°C or 32°C for 40, 55, and 70 days were used for chemical and sensory analysis. In both low and high tannin wines, storage at 32°C resulted in significant increase in small polymeric pigment (SPP) (p ≤ 0.05) with a corresponding decrease in anthocyanin concentrations over time, which was more pronounced in Cabernet Sauvignon. In both varieties, high tannin wines contained more large polymeric pigment (LPP) than the low tannin wines (p ≤ 0.05). Generally, titratable acidity and pH were not affected by storage treatments. A trained sensory panel (n = 21) gave higher astringency ratings to high tannin wines than low tannin wines for both varieties, which remained constant throughout the study. An increased perception of bitterness was associated with storage at 32°C storage for 70 days, while alcohol burn intensity was comparable in Cabernet Sauvignon. No significant differences in bitterness and alcohol burn intensity were found in Merlot. Results indicate that storage temperature and storage time contributed to changes in the chemical composition of typically aging red wines but did not impact perceived astringency. Tannin concentration was positively correlated with perceived astringency (r = 0.882) in Cabernet Sauvignon, while SPP and LPP had lower correlation with perceived astringency for both varieties.