Chapter 7

Malolactic Fermentation in Wine

Wines Benefiting from Malolactic Fermentation

Grapes grown in a cooler climate tend to have higher acidity levels, generally due to the significant amount of malic acid. Wines from these high acid musts can benefit from malolactic fermentation (MLF). On the other hand, grapes produced in very warm climates lack natural acidity and do not benefit from the process because it makes them less balanced and unstable. For this reason, in these wines, malolactic fermentation is discouraged. However, even if malic acid levels are high, the decision to choose malolactic fermentation should be based on the style of wine and the acid profile of the must and the variety of the grapes. Red wines (medium- to full-bodied) more commonly benefit from MLF than whites, where high acidity is a key character of the wine, particularly high acid whites such as Riesling and Sauvignon Blanc. White wines benefiting most from malolactic fermentation are champagnes, full-bodied dry whites (classic Burgundian whites, such as Chardonnay and Viognier).

Red Wines

Red wines contain tannins, which contribute to the astringent taste. Acidity in wine tends to enhance astringency; therefore, red wines (rich in tannins) often undergo malolactic fermentation to lower acidity.

White Wines

Malolactic fermentation contributes to the aromatic complexity of Chardonnay wines. Malolactic fermentation does not lessen the varietal aroma of Chardonnay; on the contrary, it develops and stabilizes certain aromatic and textural nuances, making the wine more complete. On the other hand, it is important to mention that there are many Chardonnay's in the world that are crispy showing citrus, green apple aromas without any malolactic fermentation. The milder fragrance of most white wines makes them more susceptible to potentially undesirable flavor changes induced by malolactic fermentation. Grape varieties such as Riesling, Gewurztraminer, Pinot Gris, Sauvignon Blanc, Chenin Blanc, and Muscat that show more fruity, floral profile with high acidity usually do not undergo malolactic fermentation.

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