Effects of the gas phase composition of fermenting must on volatiles of grape berries during anaerobic metabolism.

Traditional Beaujolais vinification begins with fermentation of uncrushed g rapes in presence of must. The process involves three different phases: mus t inoculated with selected yeast, uncrushed grape berries submerged in the fermenting must and upper berries emerging from the liquid, in contact with headspace gases. Laboratory experiments showed that intact berries could a bsorb volatile compounds released by the fermentation of the must, as alcoh ols, esters, acids etc. present in the headspace of the glass jars. The imp act of volatile compounds released by the fermenting must on intact berries was studied and compared with regular carbonic maceration (without juice). The solubilizating effect of ethanol on volatile phenols was underlined. A n analysis of some odour active components was performed.