Emerging trends in the application of malolactic fermentation

Deacidification of wines by malolactic fermentation (MLF) is an essential step in the production of most red, many white and some sparkling base wines. While this secondary fermentation can occur spontaneously, the majority of winemakers, particularly in new world winemaking regions, prefer to minimise the risk of a failed or sluggish MLF by inoculating with a reliable, commercially available starter culture. This review focuses on the scientific literature underpinning growing trends in the application of MLF starters. It considers the literature on co-inoculation regimes, where MLF bacteria are inoculated into a ferment prior to completion of alcoholic fermentation and what benefits this might bring relative to sequential inoculation, when bacteria are added after completion of primary fermentation. It also considers the benefits of the growing trend of using bacteria other than the traditional Oenococcus oeni for induction of MLF, and of developing starter cultures from regional isolates of MLF bacteria to enhance regional identity of wines.