What is the impact of maleolactic fermentation on wine?

Impact of Malolactic Fermentation on Wine

Malolactic fermentation (MLF) is a secondary fermentation in winemaking, where lactic acid bacteria convert malic acid (a harsh, tart acid) into lactic acid (a softer, smoother acid). This process has a significant impact on the final characteristics of the wine, influencing its:

1. Acidity and Flavour Profile:

* Reduced Acidity: MLF lowers the overall acidity of the wine, resulting in a smoother and softer taste.

* Flavour Development: Lactic acid bacteria produce various byproducts, including diacetyl (buttery flavour), acetoin (buttery, creamy), and various esters, which contribute to the complexity and aroma of the wine.

* Mouthfeel: The smoother acidity enhances the wine's mouthfeel, making it more pleasant and balanced.

2. Stability and Preservation:

* Improved Stability: MLF can enhance the wine's stability by removing malic acid, which can promote instability and unwanted chemical reactions.

* Enhanced Shelf Life: The conversion of malic acid into lactic acid contributes to a longer shelf life, reducing the chances of oxidation and spoilage.

3. Aromatic Profile:

* Increased Complexity: MLF can add complexity to the wine's aroma profile, introducing notes of butter, cream, and sometimes even a hint of animal notes.

* Softer Aromas: The reduction of malic acid softens the overall fruitiness, allowing other aromatic compounds to shine through.

4. Colour and Texture:

* Enhanced Colour: In red wines, MLF can enhance colour intensity by promoting the extraction of anthocyanins (red pigments) from the grape skins.

* Smoother Texture: The smoother acidity contributes to a smoother texture and mouthfeel, making the wine more enjoyable.

5. Wine Style:

* Impact on Style: MLF is often crucial for producing certain wine styles, such as Chardonnay, Pinot Noir, and Cabernet Sauvignon.

* Varietal Expression: It can enhance the varietal expression of certain grapes, bringing out specific flavour characteristics.

It's important to note that:

* MLF is not always desired and can be detrimental in some cases, depending on the specific grape variety and style of wine being produced.

* Some winemakers choose to prevent MLF through various methods, such as using sulphur dioxide or filtering the wine.

* The impact of MLF varies significantly depending on factors like grape variety, climate, and winemaking practices.

Overall, malolactic fermentation is a complex process with profound effects on the final characteristics of wine. Its impact extends beyond simply reducing acidity, influencing the flavour profile, aroma, stability, colour, and ultimately, the overall style of the wine.