Volatile acidity in wine refers to the presence of low molecular weight fatty acids that can be easily vaporized or distilled. These acids are responsible for the sour or vinegar-like smell that can be detected in some wines. As a sommelier and brewer, I have encountered volatile acidity in both wine and beer production.
One of the main components of volatile acidity in wine is acetic acid, which makes up more than 93% of the total steam distillable acids found in wine. Acetic acid is the primary acid responsible for the distinct vinegar aroma and taste. While a small amount of acetic acid can contribute to the complexity and balance of certain wines, excessive levels can be detrimental to the overall quality.
As a winemaker, controlling volatile acidity is crucial to producing high-quality wines. High levels of volatile acidity can indicate a microbial spoilage or contamination in the winemaking process. The presence of certain bacteria, such as Acetobacter, can convert alcohol into acetic acid, leading to an increase in volatile acidity. This is commonly referred to as “acetification” and can result in a wine with undesirable flavors and aromas.
To prevent or minimize volatile acidity, winemakers employ various techniques and practices. One important step is maintaining clean and sanitary winemaking conditions to prevent the growth of acetic acid-producing bacteria. This includes regular cleaning and sterilization of equipment, proper handling of grapes, and careful monitoring of fermentation conditions.
Additionally, winemakers can control volatile acidity by monitoring and adjusting the pH levels of the wine. Higher pH levels can promote the growth of bacteria that produce acetic acid, so maintaining a lower pH can help inhibit their activity. This can be achieved through the use of acid adjustments or blending with wines that have lower volatile acidity levels.
In my experience as a brewer, volatile acidity can also be a concern in beer production. While the presence of acetic acid is not desirable in most beer styles, certain styles such as sour beers intentionally incorporate acetic acid-producing bacteria to create a tart or sour flavor profile. These bacteria, such as Lactobacillus and Pediococcus, can convert sugars into acetic acid during fermentation.
Volatile acidity in wine refers to the presence of low molecular weight fatty acids, with acetic acid being the most significant component. It is generally perceived as the odor of vinegar and can greatly impact the quality of the wine. Winemakers and brewers alike strive to control volatile acidity through proper sanitation, pH management, and careful monitoring to ensure the desired flavors and aromas are achieved in the final product.