Methanol release during fermentation of red grapes treated with pectolytic enzymes

Red grapes of the Tinto fino (Vitis vinifera) variety were treated with four different commercial preparations of pectolytic enzymes, and methanol production during fermentation of the grapes was studied. Pectin content of the grapes and in the final wine were also quantified, to study the relation between methanol release and the extent of pectin degradation by the enzymes. The results showed that the enzymatic treatments enhanced the methanol content from day one of fermentation for three of the four enzymes, and from day three for all of them. Every enzymatic treatment produced higher methanol levels than the control in the final wine. During storage the methanol levels remained more or less constant.