The total acidity of a wine is the result of the contribution of nonvolatile or fixed acids such as malic and tartaric plus those acids separated by steam volatilization. A measure of volatile acidity is used routinely as an indicator of wine spoilage (Table 11.1). Although generally interpreted as acetic acid content (in g/L), a traditional volatile acid analysis includes all those steam-distillable acids present in the wine. Thus, significant contributions to volatile acidity (by steam distribution) may be made by carbon dioxide (as carbonic acid); sulfur dioxide (as sulfurous acid); and, to a lesser extent, lactic, formic, butyric, and propionic acids. In addition, sorbic acid (added to wine as potassium sorbate), used as a fungal inhibitor, is also steam-distillable and should be taken into consideration when appropriate. The contributions of CO2, SO2, and sorbic acid interferences are discussed in Chapter 20 (Volatile Acidity).
KeywordsLactic Acid Bacterium Volatile Acidity Wine Yeast Sorbic Acid Acetic Acid Bacterium
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