Lactic acid is an organic acid found in fermented foods and beverages, including wine, yoghurt and cultured dairy products. In winemaking, it is produced primarily when lactic acid bacteria convert malic acid into lactic acid during malolactic fermentation. This process generally reduces perceived sharpness and can change the wine’s texture and aroma.
Malolactic fermentation converts the sharper-tasting malic acid into softer lactic acid and carbon dioxide. The process often makes a wine feel rounder and less sharply acidic. It is common in most red wines and is used selectively in white wines, especially Chardonnay.
Lactic acid is associated with a softer, rounder acidity than malic acid. Wines that undergo MLF may also develop buttery or creamy aromas due to diacetyl and other compounds, but lactic acid itself is not the direct cause of every buttery note. The overall effect depends on bacterial activity, lees contact, oxygen and cellar management.
Example: a Chardonnay that undergoes malolactic fermentation may have a softer acidity and a rounder palate than a crisp Chardonnay in which MLF has been prevented.
Tartaric acid is the principal stable acid in grapes and wine. Malic acid contributes a sharper, green-apple character. Lactic acid is softer and is produced during malolactic fermentation. These acids contribute differently to the wine’s total acidity and sensory balance.
Chef’s note: wines with a softer lactic profile can suit rich seafood, poultry and creamy sauces. Pair according to the wine’s actual acidity, body and oak influence rather than assuming every MLF wine is buttery.
This term is one of hundreds covered in depth across OCS courses, learning paths, and 1-on-1 coaching with Chef Eric.
