Malolactic Fermentation (ML): A bacterial conversion occurring in most wines, this natural process converts sharper malic acid (found in green apples) into softer lactic acid (found in milk). Total acidity is reduced; the wines become softer, rounder and more complex. In addition, malolactic fermentation stabilizes wines by preventing an undesirable fermentation in the bottle. Often called the secondary fermentation. Frequently associated with big, rich, buttery Chardonnay, malolactic fermentation is prevented when fresher, crisper styles are desired.