Which term describes the natural process where bacteria convert malic acid to lactic acid?

The term that describes the natural process where bacteria convert malic acid to lactic acid is malolactic fermentation. This process is significant in winemaking as it helps soften the wine's acidity and can contribute to the complexity of its flavor profile. During malolactic fermentation, lactic acid bacteria, particularly Oenococcus oeni, metabolize the sharper malic acid, which is found in grapes, and convert it into the smoother-tasting lactic acid.

This transformation is particularly valuable for red wines and some fuller-bodied white wines, as it enhances the overall mouthfeel and taste, making wines more approachable. Additionally, malolactic fermentation can result in the production of other compounds that add to the wine's aroma and flavor nuances, such as diacetyl, which imparts a buttery note.

The other terms, while relevant in the winemaking process, refer to different processes. Fermentation generally refers to the initial alcoholic fermentation where yeasts convert sugars into alcohol and carbon dioxide. Filtration is a clarification process aimed at removing solids from the wine, while clarification itself refers to the methods used to make the wine clear by removing suspended particles. Understanding these terms in the context of winemaking helps clarify the role and importance of malolactic fermentation