Abstract: The Labrusca Flavour Index (LFI) of grape wine made from Labrusca grapes is decreased substantially by subjecting grape juice or wine produced from the grape juice to reverse osmosis with a semi-permeable membrane at ambient temperatures to cause the low molecular weight volatile esters, especially methyl anthranilate, to pass through the semi-permeable membrane. The reverse osmosis usually is effected with a membrane having a molecular weight cut-off of about 200 which enables colorants and sugars to be retained. By decreasing the LFI value of the wine, larger proportions may be used to blend with less proportions of higher quality Vinifera wines.