What is Malolactic Fermentation?
Winemaking is a process that involves a series of transformations. One of the lesser-known but crucial stages in this process is malolactic fermentation (MLF). While primary fermentation converts sugars into alcohol, malolactic fermentation adds complexity, flavor, and stability to the wine. Malolactic fermentation is a secondary fermentation process that occurs in winemaking, primarily with red wines and some fuller-bodied white wines. Unlike the primary fermentation, which involves the conversion of sugars into alcohol by yeast, malolactic fermentation is a bacterial transformation.
During malolactic fermentation, malic acid (found in grapes) is converted into lactic acid and carbon dioxide. This process is driven by lactic acid bacteria, specifically strains like Oenococcus oeni, (I am sure I spelled this wrong). The result is a decrease in acidity and the development of softer, rounder, and more complex flavors in the wine. Malolactic Fermentation is important for a few reasons.
First It reduces acidity. Malic acid, present in grapes, is sharper and more tart than lactic acid. By converting malic acid into lactic acid, the wine undergoes a reduction in acidity, resulting in a smoother and more palatable taste. It also makes wine taste better. Malolactic fermentation introduces new flavor compounds into the wine. Diacetyl, a byproduct of MLF, contributes a buttery and creamy texture, while other compounds add complexity and depth to the wine's flavor profile.
MLF can also enhance a wine's stability by reducing the risk of microbial spoilage. The increase in alcohol content and the production of antimicrobial compounds during primary fermentation make the environment less favorable for spoilage organisms. Aroma Changes can also occur changing the aromatic characteristics of the wine. MLF can lead to the formation of compounds that contribute to the wine's bouquet, making it more aromatic and appealing.
Winemakers carefully control when malolactic fermentation occurs. In some cases, MLF is intentionally encouraged immediately after primary fermentation, while in others, it is delayed until after the wine has been aged in barrels. The choice of timing depends on the winemaker's desired style and the characteristics they aim to achieve in the final product.
It's important to note that not all wines undergo malolactic fermentation. Some winemakers prefer to retain the natural acidity of the grapes, especially in crisp and refreshing white wines.
Malolactic fermentation may operate behind the scenes, but its impact on the final wine is significant. The delicate dance between bacteria and acids during MLF transforms a young, vibrant wine into a more refined and complex masterpiece.
