Malolactic fermentation (also known as
malolactic conversion or
MLF) is a process in
winemaking in which
tart-tasting
malic acid, naturally present in
grape must, is converted to softer-tasting
lactic acid. Malolactic fermentation is most often performed as a
secondary fermentation shortly after the end of the primary
fermentation, but can sometimes run concurrently with it. The process is standard for most red wine production and for some white
grape varieties such as
Chardonnay, where it can impart a "buttery" flavor from
diacetyl, a byproduct of the reaction.