Malolactic Fermentation

MLF converts the harsher diprotic malic acid into the softer monoprotic lactic acid, carried out by lactic acid bacteria (LAB), most commonly Oenococcus oeni.

When to encourage MLF

• All red wines — improves softness, reduces green harshness, enhances complexity
• Chardonnay and other full-bodied whites — adds creamy, buttery diacetyl character

When to prevent MLF

• Crisp aromatic whites (Riesling, Pinot Grigio) — MLF flattens the acid and mutes fresh fruit
• Wines already low in acidity

Conditions for MLF

• Temperature: 18–22°C
• pH: 3.2–3.5
• Free SO₂ <10 mg/L
• Alcohol <14%