Which type of lactic acid bacteria to use, Oenococcus oeni or Lactobacillus plantarum, is not important as both convert malic acid to lactic acid. The key point is that they both add value by contributing to the aroma and flavour of the wine. These interesting contributions are achieved thanks to the different inoculation times, the use of a certain type of bacteria, and the different vessels used. Another important effect is the ability of bacteria to protect the wine (microbiological and protein stabilisation). In other words, bacteria offer different tools, the important thing is to know which ones to use depending on the objective: speed, stability, aromatic diversity.

Maret du Toit, a researcher at the Institute for Wine BioTechnology in Stellenbosch, South Africa, considered one of the world’s leading experts on this subject, describes the different factors that influence the sensory impact of malolactic fermentation on wine, and in particular the effect of pH, ethanol, malic acid concentration, interaction with yeasts, nutrients and type of inoculation.

Next, Elda Lerm, Anchor Oenology, breaks down the 4 key issues that the winemaker must consider: whether or not to perform MLF, whether to inoculate or let it occur spontaneously, when to inoculate, and which bacteria to use. She explains the pros and cons of each of these decisions while also analysing other practical aspects such as the effect of using tannins, micro-oxygenation, indigenous populations, contaminating micro-organisms, contact with the lees.

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The presentations shown in these videos were given at Enoforum 2022 (Zaragoza, 20-21 April 2022) in the module organised in collaboration with ANCHOR OENOLOGY.