Malolactic fermentation in wines

Malolactic fermentation (MLF) is a fascinating oenological process that significantly influences the complexity and character of many wines. Although its name may sound technical, its impact on the wine industry is considerable and deserves detailed exploration.
Malolactic fermentation is a stage after alcoholic fermentation in winemaking. While alcoholic fermentation transforms sugars into alcohol, malolactic fermentation focuses on the conversion of malic acid, a sharper acid present in grapes, into lactic acid, a milder acid. This process is usually carried out by lactic bacteria, especially by the bacteria Oenococcus or Lactobacillus.
The transformation of malic acid into lactic acid during malolactic fermentation has several implications for the characteristics of wine. First, it reduces the overall acidity of the wine, providing a smoother sensation on the palate. This is particularly beneficial in red wines, where malic acid can be more pronounced, and MLF contributes to greater harmony between acidity and other components.
The MLF also influences the aromas and flavors of the wine. During the process, secondary compounds are generated, such as diacetyl, which can give the wine buttery or creamy notes. These aromas and flavors add complexity and can improve the texture of the wine, providing a richer, more rounded sensory experience.
The decision to carry out malolactic fermentation or not depends on multiple factors, including the type of wine being made, the desired style, and the winemaker's preferences. Some wines, especially fresh, crisp whites, often do not undergo MLF to preserve vibrant acidity and freshness. On the other hand, many red wines, especially those intended for aging, often undergo this process to soften structure and improve complexity.
MLF does not always occur spontaneously, and in some cases, winemakers may choose to control and facilitate the process by adding specific strains of lactic acid bacteria. This control allows winemakers to influence the aromatic and flavor profile of the wine, ensuring that it aligns with their objectives and quality standards.
In addition to its impacts on the organoleptic quality of wine, malolactic fermentation can also be a useful tool for stabilizing wine. Reducing acidity through malic acid conversion can help prevent tartaric acid crystal precipitation problems in bottled wine, improving its clarity and stability over time.
It is important to note that while MLF is largely beneficial and desired in many cases, it is not appropriate for all wines. Some styles, such as certain high-acid white wines, can lose their freshness and vitality if they undergo malolactic fermentation. Choosing to perform or avoid this process requires in-depth knowledge of the grapes, the desired wine, and the experience and preferences of the winemaker.
Malolactic fermentation is not only relevant in red wine making, but has also gained popularity in some white and sparkling wines. In these cases, MLF can add complexity and smoothness, contributing to the evolution of the wine over time. The diversity of styles and approaches in winemaking is what makes malolactic fermentation a valuable and versatile tool for winemakers.
In summary, malolactic fermentation is a key component in creating complex and balanced wines. Its ability to soften acidity, improve texture and add layers of aromas and flavors makes it a fascinating and relevant process in modern winemaking. The decision to use FML requires a careful balance, considering the desired style of wine and the art of the winemaker to obtain results that delight the most demanding palates.