What is Malolactic Fermentation in Wine-Making?

In the vast world of winemaking, there are numerous processes and techniques that can greatly influence the flavor, texture, and overall profile of the final wine. One such process, often overlooked but undeniably significant, is malolactic fermentation. In this friendly and easy-to-understand deep-dive article, we’ll explore the ins and outs of malolactic fermentation, highlighting its impact on winemaking and providing examples of popular wine varieties that undergo this process. So, let’s raise a glass and journey together into the intriguing world of malolactic fermentation.

Malolactic Fermentation: The Basics

Malolactic fermentation (MLF) is a secondary fermentation process that occurs in many wines after the primary alcoholic fermentation. During MLF, lactic acid bacteria, primarily Oenococcus oeni, convert malic acid, a naturally occurring acid in grapes, into lactic acid and carbon dioxide. This process reduces the wine’s overall acidity, resulting in a rounder, softer mouthfeel, and can also contribute to the development of certain flavors and aromas.

The Impact of Malolactic Fermentation on Wine

The decision to encourage or inhibit malolactic fermentation can significantly affect the final wine’s character. Here are some key ways in which MLF can impact wine:

  1. Acidity: By converting the sharper, more tart malic acid into the softer, creamier lactic acid, MLF lowers the wine’s acidity, creating a smoother, more rounded mouthfeel.
  2. Flavor: MLF can contribute to the development of certain flavors, such as buttery or creamy notes in white wines and earthy or savory notes in red wines.
  3. Stability: Completing malolactic fermentation can help stabilize a wine by reducing the risk of undesirable bacterial spoilage, which could occur if MLF were to start unintentionally after bottling.
  4. Complexity: In some cases, MLF can add complexity and depth to a wine, particularly in reds, by allowing the development of secondary and tertiary flavors.

Wine Examples: To MLF or Not to MLF?

Whether a winemaker chooses to encourage or inhibit malolactic fermentation depends on the desired style, varietal character, and regional traditions. Here are some examples of popular wine varieties and how they are typically treated with respect to MLF:

  1. Chardonnay: Chardonnay is a versatile grape variety that can produce a wide range of styles. In regions such as Burgundy and California, where richer, more opulent styles of Chardonnay are popular, MLF is often encouraged, resulting in wines with buttery, creamy flavors and a lush mouthfeel. In contrast, Chardonnay from cooler regions, such as Chablis or some areas of Australia, may undergo partial or no MLF to preserve the wine’s natural acidity and crisp, mineral-driven character.
  2. Sauvignon Blanc: In general, Sauvignon Blanc wines are characterized by their bright acidity and zesty, citrus-driven flavors. To maintain this fresh and vibrant profile, many winemakers choose to inhibit malolactic fermentation in Sauvignon Blanc wines. However, some producers, particularly those crafting high-end, barrel-aged Sauvignon Blancs or Sauvignon Blanc-Sémillon blends, may opt for partial MLF to add complexity and texture.
  3. Red Wines: Most red wines, particularly those with moderate to high acidity, such as Cabernet Sauvignon, Merlot, and Pinot Noir, undergo malolactic fermentation. MLF helps to soften the wine’s acidity, integrate tannins, and develop savory, earthy flavors that can add complexity and depth.

The next time you sip on a glass of wine, take a moment to consider the role of malolactic fermentation in creating the wine’s unique character, and let your newfound knowledge enhance your wine-tasting experience.

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Written by

Bernard Marr has a deep passion for wine. He has written hundreds of articles on wine, including features for Forbes, covering wine-making and industry trends. Away from the world of wine, Bernard is a world-renown business and technology futurist. He is the award winning author of over 20 best-selling books and has a combined audience of nearly 4 million people across his social media channels and newsletters.

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