Malo-Lactic Fermentation in South African Table Wines

Abstract

A survey of the incidence of malo-lactic fermentation in South African table wines, particularly red table wines, was made for the first time in this country. In young unfinished red table wines the incidence of malo-lactic fermentation was 27.5%, whereas 66.2% of finished and bottled commercial red table wines, without any defects, had undergone malo-lactic fermentation. None of the finished and bottled white and rosé table wines which were analyzed, had undergone malo-lactic fermentation. The incidence of malo-lactic fermentation in wines shortly after alcoholic fermentation depended to a considerable extent on time of racking and SO₂ addition. Delayed racking without SO₂ addition greatly stimulated malo-lactic fermentation, whereas prompt racking, with SO₂ (40-60 ppm), strongly reduced the incidence of malo-lactic fermentation. The incidence of malo-lactic fermentation also depended on storage conditions. Red table wines were more susceptible when stored in wooden instead of stainless-steel or glass containers. In wooden containers, susceptibility increased with increasing storage period. The incidence of malo-lactic fermentation was about equal for award-winning and non-award-winning red table wines. This phenomenon contradicted the general belief that malo-lactic fermentation is detrimental to the quality of red table wines in warm regions.