Mls In Bottle Of Wine

Uncorking the Mystery: Understanding MLS in a Bottle of Wine

Wine, a beverage enjoyed for millennia, holds a complex tapestry of flavors, aromas, and subtleties that depend heavily on its production process. One often-overlooked yet crucial aspect is the presence of microbial life, specifically Malolactic Lactic fermentation (MLS), commonly known as malolactic fermentation. This article delves into the intricacies of MLS in wine, explaining its process, effects on the wine's characteristics, and why it's a significant factor in winemaking. Understanding MLS allows for a deeper appreciation of the nuanced flavors and textures found in your favorite bottle. We’ll explore everything from the science behind it to its impact on various wine styles.

What is Malolactic Fermentation (MLS)?

Malolactic fermentation is a secondary fermentation process in winemaking where malic acid, a naturally occurring sharp acid in grapes, is converted into lactic acid, a softer, less harsh acid. This transformation is carried out by specific bacteria, primarily Oenococcus oeni. The process is naturally occurring in some wines, but winemakers often encourage it through specific techniques to achieve desired flavor profiles.

Malic acid, a relatively harsh acid, contributes to a wine's high acidity and a somewhat green or tart flavor. Lactic acid, on the other hand, possesses a smoother, creamier character, which reduces the wine's overall acidity and softens its astringency. The conversion of malic acid to lactic acid is a biochemical reaction where malic acid loses a carbon dioxide molecule, resulting in the production of lactic acid and carbon dioxide.

The presence of this carbon dioxide, although less noticeable than in primary fermentation, can contribute to a subtle effervescence or a gentle fizziness, depending on the wine and how it's handled. The release of CO2 during MLS is often less dramatic than during alcoholic fermentation, and it's typically absorbed into the wine itself or dissipates naturally.

The Process of Malolactic Fermentation

The initiation and progression of MLS are contingent upon several factors, creating a dynamic and nuanced process. It's crucial to remember that this is a biological process, making it vulnerable to various influencing factors.

• Bacteria Presence: The presence of Oenococcus oeni is paramount. These bacteria are naturally found on grape skins but are also often added by winemakers as a starter culture. The starter culture ensures a reliable and consistent malolactic fermentation.

• pH Level: The pH of the wine, a measure of its acidity, greatly impacts MLS. A higher pH (less acidic) typically favors the bacteria, while lower pH levels can inhibit or prevent the fermentation. Winemakers often monitor and adjust the pH to optimize conditions for MLS.

• Sulfur Dioxide (SO2) Levels: SO2 is a common preservative in winemaking. High levels of SO2 can significantly inhibit the growth of Oenococcus oeni, potentially preventing or slowing down MLS. Careful management of SO2 levels is crucial for successful malolactic fermentation.

• Temperature: Temperature plays a crucial role in the rate of MLS. Generally, warmer temperatures (around 60-70°F or 15-21°C) are more conducive for bacterial growth, while cooler temperatures slow the process down.

• Nutrient Availability: The bacteria require nutrients to thrive and carry out the conversion. These nutrients are naturally present in some wines, but deficiencies can be addressed by adding specific nutrient supplements. These might include yeast hulls or diammonium phosphate.

• Wine Style and Grape Variety: The suitability of MLS differs based on grape varietals and the desired style of the wine. Some grape varieties naturally exhibit better conditions for MLS than others.

The entire process can last anywhere from a few weeks to several months, depending on these factors. Winemakers closely monitor the progress of MLS, utilizing various techniques to ensure its completion or halt it if necessary. This monitoring is crucial to preventing off-flavors, ensuring a smooth fermentation, and achieving the desired characteristics in the finished wine.

Effects of MLS on Wine Characteristics

The impact of MLS on the sensory characteristics of wine is significant, influencing various aspects of its final profile. The effects aren't merely about reducing acidity; they encompass a wider range of alterations that collectively contribute to the wine's unique personality.

• Reduced Acidity and Harshness: The most prominent effect is the reduction in malic acid's sharp, tart character. This results in a smoother, rounder mouthfeel and less astringency.

• Enhanced Flavor Complexity: The conversion process creates several by-products that contribute to the wine's complexity. These by-products include diacetyl, a buttery compound that adds creamy notes, and other volatile compounds that enhance the aromatic profile of the wine.

• Increased Body and Texture: The softening of the acidity and the addition of buttery notes generally enhance the wine's mouthfeel, making it seem fuller and richer.

• Improved Microbial Stability: Lactic acid produced during MLS is less prone to bacterial spoilage than malic acid, therefore the process contributes to a longer shelf-life.

• Development of Specific Aromas: The specific aromas imparted by MLS depend on various factors like grape variety, winemaking practices, and the particular bacterial strains involved. Certain aromas associated with MLS include buttery notes, creamy textures, hints of butterscotch, and a general softening of fruit flavors.

MLS and Different Wine Styles

The application of MLS varies significantly across different wine styles. Some wines benefit greatly from this secondary fermentation while others are better left without it. The decision to implement MLS is a crucial aspect of winemaking, dependent on the desired stylistic outcome.

• Red Wines: MLS is commonly employed in many red wines, particularly those intended to have a soft, approachable character. It is particularly relevant in wines like Pinot Noir, Cabernet Franc, and Merlot, where it contributes to a smooth, rounded mouthfeel and complexity.

• White Wines: MLS is used less frequently in white wines, but it is employed in certain styles like Chardonnay. In Chardonnay, MLS often enhances its buttery and creamy notes, enhancing its richness and complexity. However, it's crucial to note that this can depend on the winemaker’s style and the specific characteristics of the vintage.

• Rosé Wines: MLS is rarely used in Rosé wines as the softer characteristics often clash with the intention of maintaining freshness and lighter fruit notes.

• Sparkling Wines: MLS is seldom used in sparkling wines as the additional carbon dioxide produced can cause unwanted pressure within the bottle.

The decision to employ MLS ultimately rests on the winemaker's stylistic vision and the suitability of the wine’s characteristics. It's a crucial element in tailoring the wine’s final expression.

Troubleshooting Malolactic Fermentation

While MLS is a beneficial process for many wines, it’s not without its challenges. Winemakers need to actively monitor and manage the process to ensure successful completion and prevent potential issues.

• Stuck or Slow Fermentation: This can occur due to various factors such as low pH, high SO2 levels, insufficient nutrients, or unfavorable temperatures. Addressing these factors, including potentially adding nutrients or adjusting temperature, can often resolve the issue.

• Off-Flavors: Improper management of MLS can sometimes lead to off-flavors, including a "mousey" or "geranium" aroma. These are often caused by undesirable bacteria and can be prevented through careful hygiene, appropriate temperature control, and the use of suitable bacterial strains.

• Unwanted Diacetyl Production: While diacetyl contributes to buttery notes, excessive production can lead to overly intense and undesirable buttery or butterscotch flavors. This is often controlled through careful management of temperature and fermentation conditions.

Frequently Asked Questions (FAQ)

Q: Is MLS always desirable in winemaking?

A: No, MLS isn't always desirable. While it enhances many wine styles, certain wines, like those emphasizing freshness and bright acidity, are better left without it. The decision is based on the desired style and characteristics of the wine.

Q: Can I tell if a wine has undergone MLS?

A: It's not always easy to tell just by tasting, but some clues might include a softer acidity, creamier mouthfeel, and the presence of buttery or nutty notes. However, these characteristics can also be influenced by other factors, so it's not a definitive indicator.

Q: Is MLS harmful to humans?

A: No, the lactic acid produced during MLS is a natural acid found in many foods and is not harmful to humans.

Q: What happens if MLS doesn't happen?

A: If MLS doesn't occur, the wine will retain its higher acidity and sharper, tarter profile. This can be desirable in certain styles but might result in a less complex or less approachable wine in others.

Conclusion

Malolactic fermentation is a complex yet crucial process in winemaking. Understanding its science, its impact on wine characteristics, and its role in different wine styles offers a deeper appreciation for the complexities of wine production. While the presence of MLS isn't always guaranteed or even desired, its potential to transform the sensory attributes of wine is undeniable. The careful management and understanding of this process are key for winemakers seeking to craft wines with precisely the desired characteristics, making it an essential aspect of winemaking expertise. From the subtle buttery notes to the smoother mouthfeel, MLS contributes significantly to the rich tapestry of flavors found in the world of wine.