Volatile compounds are lost during grape must fermentation owing to escaping carbon dioxide, which ultimately affects the wine’s aroma. An innovative condensation device was designed to trap organic volatile compounds that would otherwise be lost. Trials were performed on Sangiovese and Syrah grapes and involved continuous condensation of vapor (condensed fractions, CFs) escaping from fermentation tanks. Daily measurements were taken of the ethanol content and volatile compound composition of CFs. An average of 1.3g of CF per kilogram of fermenting must was recovered, corresponding to a theoretical yield of condensed product of about 0.37%. Mean ethanol content was about 24% by volume, while the total organic volatile compound concentration was about 1200 mg L−1. Predominant compounds were alcohols and esters of secondary origin, with four compounds (ethyl octanoate, 1-propanol, ethyl acetate, and 2, 3-butanediol) accounting for more than 88% of the final concentration. The CF volatile profile changed as a function of fermentation time. CFs were added back to their respective wines for sensory evaluation and were statistically shown to be detectable at a rate of 1‰.
A Condenser to Recover Organic Volatile Compounds during Vinification
GUERRINI, LORENZO;
2016
Abstract
Volatile compounds are lost during grape must fermentation owing to escaping carbon dioxide, which ultimately affects the wine’s aroma. An innovative condensation device was designed to trap organic volatile compounds that would otherwise be lost. Trials were performed on Sangiovese and Syrah grapes and involved continuous condensation of vapor (condensed fractions, CFs) escaping from fermentation tanks. Daily measurements were taken of the ethanol content and volatile compound composition of CFs. An average of 1.3g of CF per kilogram of fermenting must was recovered, corresponding to a theoretical yield of condensed product of about 0.37%. Mean ethanol content was about 24% by volume, while the total organic volatile compound concentration was about 1200 mg L−1. Predominant compounds were alcohols and esters of secondary origin, with four compounds (ethyl octanoate, 1-propanol, ethyl acetate, and 2, 3-butanediol) accounting for more than 88% of the final concentration. The CF volatile profile changed as a function of fermentation time. CFs were added back to their respective wines for sensory evaluation and were statistically shown to be detectable at a rate of 1‰.
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