The Malo-Lactic Fermentation in New York State Wines

Abstract

Wines from Vitis labrusca grapes and their hybrids produced in New York State were examined to determine the incidence of malo-lactic fermentation. Ninety-six samples of partially ameliorated varietal wines were analyzed for organic acids by paper chromatography. Forty-five percent had undergone a malo-lactic fermentation. The incidence was much greater in red wines than in white wines. There was a marked difference in incidence among the wineries involved, and the correlation between must handling procedures and incidence of malo-lactic fermentation was noted.

The time interval between the alcoholic fermentation and a malo-lactic fermentation was found to be of the order of three weeks. The conversion of malic acid to lactic acid in these wines occurred rapidly, once started, and coincided with the development of a bacterial population in excess of a million organisms per milliliter. Three types of lactic acid organisms have been isolated, a heterofermentative rod, a homofermentative rod, and a homofermentative coccus.

Characteristics of musts were reported. In the new wines, the relationship between total acidity and pH, and the incidence of malo-lactic fermentation was noted.