Malolactic fermentation is commonly referred to as "MLF", or (in winemaker's speak as) "malo" (pronounced may-low). So if MLF is a type of fermentation, what ferments, what does the fermenting, and most importantly, what sort of changes does MLF make to the final sensory quality of the wine? MLF usually occurs shortly after the end of the primary fermentation (when the grape sugar is converted to alcohol by yeast). It is undertaken by the family of lactic acid bacteria (LAB); Oenococcus oeni, and various species of Lactobacillus and Pediococcus. The primary function of all these bacteria is to convert one of the two major grape acids found in wine called L- malic acid, to another type of acid, L-lactic acid. This conversion is accompanied by the production of carbon dioxide (so hence the term, fermentation). Lactic acid tastes markedly less sour than malic acid. In addition lactic acid has a mouthfeel "softness" about it in comparison to the oft described "hard" and "metallic edged" malic acid. In short, MLF results in a natural de- acidification and softening of the wine's palate. Grapes produced in cool regions tend to be high in acidity much of which comes from the contribution of malic acid. For wines produced from such grapes, de-acidification via MLF is particularly useful as it results in a more balanced and palatable wine.