A Condenser to Recover Organic Volatile Compounds during Vinification

Abstract

Escape of carbon dioxide during grape must fermentation leads to loss of volatile compounds, 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 using Sangiovese and Syrah grapes and involved continuous condensation of vapor (condensed fractions, CFs) that escaped from fermentation tanks. Ethanol content and volatile compound composition of CFs were measured daily since 48 hr after the fermentation began. An average of 1.3 g CF per kg fermenting must was recovered, corresponding to a theoretical yield of ~0.37% of condensed product. Mean ethanol content was ~24% by volume, and the total concentration of organic volatile compounds was ~1200 mg/L. 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. For sensory evaluation, CFs were added back to their respective wines and were statistically shown to be detectable at a rate of 1‰.