Malolactic fermentation

Malolactic fermentation is a transformation that often takes place in wine after the ordinary alcoholic fermentation. Here the sharp malic acid, the kind you know from a green apple, is turned into a softer lactic acid, the type of acid you meet in dairy products. The result is a wine that feels rounder and milder in the mouth, because the fresh, slightly biting acidity is toned down. It is not a fermentation in the classic sense, where sugar becomes alcohol, but a process driven by bacteria, and many winemakers deliberately control whether or not it should happen.

For you as a drinker, it matters a great deal for how the wine tastes and feels. A wine that has gone through full malolactic fermentation comes across as softer and can take on creamy, buttery tones, something you often meet in full-bodied white wines. If you want to preserve a fresh, crisp and fruity character instead, the winemaker holds the process back, which is common in many light, crunchy white wines and in mousserende vin.

Most red wines have gone through it, often without it being mentioned, so here it is rarely something you need to think about. A widespread misunderstanding is that buttery notes always come from barrel ageing. To a large extent they stem from precisely this process, and you can meet them even in wines that have never seen an oak barrel.