Methanol in Wines in Relation to Processing and Variety

Abstract

The formation of methanol by natural grape enzymes acting on pectins was studied in relation to the grape varieties and processing techniques. Concord wine fermented in the presence of the grape skins without heat treatment contained the highest amounts of methanol. Wines made from white grape varieties of Vitis vinifera, V. labrusca, and hybrids contained less methanol than red varieties. Wine made from hot-pressed grapes had about 10-20% of the methanol content of the same varietal wines fermented on the skins. There was a comparatively high amount of methanol in wines made from 'Concord' or 'Ives' grapes (400 to 500 ppm) though it varied widely in 4 separate harvest years. Wines prepared from the vinifera grapes 'Pinot noir' or 'Riesling' contained low amounts of methanol and were more uniform year to year.