By Kori ~ July 23rd, 2009.
This weekâ€™s Wine Word of the Week is volatile acidity.
Official definition from Jancis Robinsonâ€™s The Oxford Companion to Wine:
Volatile acidity of a wine is its total concentration of volatile acids, those naturally occurring organic acids that are separable by distillation. Wineâ€™s most common volatile acid by far is acetic acid (more than 96 per cent), which is why it is used as the routine measure of volatile acidity (VA). â€¦.
Acetic acid, in small amounts, is a byproduct of the normal action of yeast in grape juice. However, the major source is the action of a group of bacteria known as acetobacter which require oxygen for their growth and survival, and cause a reaction between the alcohol of a wine and the oxygen to produce acetic acid. Very low concentrations of acetic acid, below 0.2 g/l, do not affect the taste adversely. Increasing concentrations change the taste of the wine, however, from added complexity and fruitiness to a frankly vinegary flavor at levels much above 1.5 g/l.
Laymanâ€™s terms from Kori:
Volatile acidity, caused most often by acetic acid, is the result of oxidation during winemaking. Excessive amounts of volatile acidity are considered a wine fault and are characterized by the unpleasant smell of vinegar or nail polish remover.
Filed under: Wine Word of the Week