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How It Changes Flavor
Buttery, creamy, smooth. The most famous MLF flavor is buttery — caused by a chemical called diacetyl, the same compound that makes movie-theater popcorn taste like butter. In Chardonnay, this is loved or hated; in red wine it's almost imperceptible, just adding background richness.
The bigger change is texture. A wine without MLF feels sharp and angular. A wine with MLF feels round and silky. This is why MLF is sometimes called “the softening fermentation.” It's not adding flavor as much as removing aggression.
Modern winemakers can control how much MLF happens. Full MLF = maximum softness, full buttery note. Partial MLF = some softening, lighter touch. No MLF = bright, sharp, food-friendly. Each style has its place.
