Introduction
Have you ever heard the term “MLF” thrown around by winemakers? If you’re a wine enthusiast, you’ve likely come across Malolactic Fermentation (MLF) as a buzzword that is often used interchangeably with the aging process. However, MLF is a critical step in the winemaking process that can significantly impact the quality and taste of wine. In this article, we provide an in-depth exploration of “what is an MLF” and why it’s crucial for winemakers.
A Comprehensive Guide to Understanding MLF
Malolactic Fermentation is the conversion of malic acid to lactic acid by bacteria, with the most commonly used bacterial strain being lactic acid bacteria (LAB). Unlike alcoholic fermentation, which is often conducted after primary fermentation, MLF usually occurs after the primary fermentation stage.
The primary fermentation occurs when yeasts convert sugars in the grape juice to alcohol, while MLF occurs when LAB converts malic acid, a naturally occurring compound in grapes, to lactic acid. The bacteria consume the malic acid and release carbon dioxide, warming the wine temperature slightly in the process. Although this process can happen naturally, many winemakers prefer to control the procedure to ensure consistency and quality.
MLF typically takes one to three months, depending on the wine’s temperature, pH, and bacterial strain. It’s usually conducted at a temperature of around 20°C to 25°C and typically requires the wine to sit in a barrel. The most commonly used method is inoculation, in which the LAB bacteria are added to the wine.
MLF is commonly used in red wine production, but it’s not exclusive to red wine. In white wine, it is used sparingly to achieve specific flavor profiles. In general, winemakers tend to use MLF on fuller-bodied, oak-aged, and higher alcohol content red wines because it produces softer acid with a smoother mouthfeel.
The Science Behind the MLF
The chemistry behind the malolactic fermentation is complex, but it’s essential to understand its basic principles. Malic acid has a rougher taste, and lactic acid has a softer, creamier taste. MLF is a process of converting malic acid to lactic acid. During the malolactic fermentation process, lactic acid bacteria convert the malic acid in wine into lactic acid and carbon dioxide. It’s a critical process that helps to modulate and reduce acidity in wine. In red wines, the process can also contribute to the wine’s complexity and body.
The Benefits of MLF in Winemaking
MLF can lead to several benefits in wine production, including enhanced flavor complexity, improved texture, and greater stability. It can also help to preserve wine and give it a smoother, more rounded feel.
One of MLF’s most significant benefits is its impact on the texture of wine. By converting sharp-tasting malic acid (found in wine grapes) into smoother-tasting lactic acid, winemakers can create a softer, creamier taste in wines. This process can also contribute to the wine’s texture, giving the wine a fuller body.
MLF can also help to stabilize wine and prevent spoilage. Bacteria in the wine can cause the wine to spoil or become volatile. By introducing LAB, wine producers can reduce the likelihood of spoilage by controlling the type of bacteria present in the wine.
How to Control MLF
To achieve consistent results in MLF, winemakers need to exercise control over the process. The first step in controlling the MLF process is to measure the wine’s pH. A lower pH often leads to greater acidity in the wine. Winemakers can also control the fermentation temperature, the inoculation time, and the bacteria strain.
Another critical control point is SO2 management. Some bacteria strains are sensitive to high SO2 levels. Thus, winemakers need to adjust the SO2 levels in their wine according to the MLF requirements.
The Impact of Different MLF Strains
LAB bacterial strains play a crucial role in MLF and have a significant effect on the wine’s flavor profile. Different strains of LAB can produce different tastes and aromas, so it’s essential to choose the right strain for the desired wine profile carefully. For example, Leuconostoc Oenos is known for its buttery, creamy flavors, while Oenococcus Oeni is known for its acidic and fruity flavors.
MLF strains can also affect the wine’s texture and mouthfeel. For example, some bacteria strains can release polysaccharides, which add to the wine’s creaminess. In contrast, others can produce diacetyl, which can lead to a more buttery taste in wine.
MLF vs. Spontaneous Fermentation
Spontaneous fermentation is a method used in winemaking whereby yeasts present in the wine ferment freely. This method doesn’t involve the addition of any commercial yeasts or bacteria, meaning that the wine’s microbial activity is entirely up to chance.
While spontaneous fermentation allows for the pure expression of grape characteristics, it also has disadvantages compared to MLF. One of the most significant drawbacks is the inconsistency of the fermentation process and the unpredictability of the outcome. Unlike the controlled nature of MLF, spontaneous fermentation can lead to unwanted off-flavors, spoilage, and other undesirable effects in wine.
How MLF Affects White Wines
MLF can also significantly impact the taste and texture of white wine production. MLF is generally used less frequently in whites as white wines have lower pH and higher acidity. However, when it is used, it results in a fuller-bodied, creamier texture and a richer mouthfeel.
MLF can have a significant impact on white wines’ flavor profile, affecting the grape’s fruity and floral aromas. In some wines, like Chardonnay, the malolactic fermentation process can contribute to buttery and nutty flavors.
Conclusion
MLF is an essential process, playing a crucial role in the winemaking process and ultimately leading to its final taste. By understanding the basic principles behind MLF, we now know the importance of controlling this process. It is essential to carefully choose the correct strain and control the parameters that affect the malolactic process to produce a consistent, high-quality product.
Whether you’re a wine enthusiast or a winemaker, it is crucial to understand the basics behind the malolactic fermentation process. By understanding what is an MLF, you can make informed decisions when it comes to your winemaking practices or the wines you choose to consume.
If you’re looking for more information about MLF and other winemaking processes, be sure to check out our other articles on the topic.