If any one has any questions or comments about the tentative program they can contact Alan Erb, the Editor of this newsletter. Regardless of whether or not the winemaker wants a malolactic fermentation to occur, knowledge of the process is essential since it can arise spontaneously and result in a change in the wine's properties. Under the proper conditions, which may arise without the winemaker's intention during primary fermentation or in the bottled wine, LAB can metabolize sugar or malic acid and alter the product. On the other hand, the malolactic fermentation may be employed to lower the acidity of the wine and to add complexity through the production of additional flavor compounds. Leuconostoc oenos or a related strain is the species of LAB that is most desired for the malolactic fermentation.
Many winemakers encourage the malolactic fermentation to occur during the primary fermentation.
While this is convenient, Leuconostoc will use sugar before malic acid, decreasing the alcohol that could be produced by the yeast and converting it instead to lactic acid. This is not necessarily a bad thing, but the winemaker should be aware of these consequences. Instead, consider using the malolactic fermentation once the primary fermentation is at or near completion, so that the sugar concentration is low and the alcohol concentration is high. Although encouraging the natural LAB is easy, it might not be the best choice. Just like the naturally occurring yeast could be used for the alcoholic fermentation, most winemakers prefer to use selected strains that produce specific effects.