How to tell if a wine has undergone malolactic fermentation

When it comes to winemaking, understanding the various processes involved in producing a bottle of wine can enhance your appreciation and enjoyment of the final product. One of these processes is , often abbreviated as MLF. This secondary fermentation can significantly impact the character, aroma, and taste of the wine. In this article, we will explore what malolactic fermentation is and how you can identify if a wine has undergone this transformation.

Malolactic fermentation refers to the conversion of malic acid, a tart and sharp compound naturally present in grapes, into lactic acid, a smoother and creamier compound. This fermentation process is carried out by bacteria, specifically strains of lactic acid bacteria such as Oenococcus oeni, which are commonly found in winery environments. Unlike primary alcoholic fermentation, which converts sugar into alcohol, malolactic fermentation takes place after the primary fermentation is complete and can occur in both red and white wines.

So, how can you tell if a wine has undergone malolactic fermentation? Here are a few observations and clues to look for:

1. A softer, creamier mouthfeel: Wines that have undergone malolactic fermentation often exhibit a smoother and rounder texture on the palate. The conversion of tart malic acid into lactic acid contributes to this change in mouthfeel. If you perceive a velvety or creamy sensation while tasting a wine, it could be an indication that MLF has occurred.

2. Reduced : Malolactic fermentation reduces the overall acidity of a wine. If you notice a mellow and less pronounced tartness, especially in white wines, this could be an indication that MLF has taken place.

3. Butter or cream-like flavors: Aromatically, MLF can introduce buttery or creamy notes to wines. This is due to the production of diacetyl, a compound responsible for buttery flavors. If you detect these flavors in your wine, especially in Chardonnay, it is likely that malolactic fermentation has occurred.

4. The absence of malic acid: The easiest way to determine if a wine has undergone malolactic fermentation is by analyzing its acid profile. By conducting laboratory tests, winemakers can measure the levels of malic acid and lactic acid present in the wine. If the malic acid levels are significantly lower or even undetectable, it indicates that MLF has likely taken place.

5. Winery practices: Sometimes, winemakers will disclose whether their wines have undergone malolactic fermentation. They may specify this on the label or provide information on their website or tasting notes. If you are curious about a particular wine, reach out to the winemaker or do some research to find out if MLF was part of their winemaking process.

It’s important to note that not all wines undergo malolactic fermentation. Some winemakers choose to preserve the natural acidity and crispness of a wine by preventing or halting MLF. This is common for certain grape varieties such as Sauvignon Blanc or Riesling, where the refreshing acidity is desired.

In conclusion, malolactic fermentation is a crucial winemaking process that adds complexity and transforms the characteristics of a wine. By paying attention to the mouthfeel, acidity, flavors, and understanding winemaking practices, you can identify whether a wine has undergone MLF. So, next time you uncork a bottle, take a moment to explore and appreciate the nuanced changes that malolactic fermentation can bring to your wine-drinking experience.