bacterial spoilage, range of wine maladies or faults including gas, haze, cloud, and off-flavours generated by the activity of bacteria in wine. These bacteria are either acetobacter or lactic acid bacteria. Acetobacter’s tendency to transform wine into vinegar can be checked by keeping air away from wine, on the part of both winemaker and wine drinker (see leftover wine). Lactic acid bacteria are more varied in their effects, which include a wide range of unpleasant-smelling compounds, depending on the type of bacterium. These are relatively rarely seen today since great care is taken by winemakers (see stabilization and hygiene) to guard against spoilage by lactic acid bacteria in the winery and to minimize the risk of a wine’s being bottled with any spoilage bacteria (see filtration, pasteurization, sterile bottling). If lactic acid bacteria do attack a wine in bottle, the results are usually detrimental to the taste and clarity of the wine, and gas is usually given off.
