Adaptation of Lactobacilli towards low pH and SO₂ to develop MLF in base musts for sparkling wines

In some white wines, malolactic fermentation (MLF) is very interesting, and for low pH wines this process is particularly difficult. Although MLF is generally not recommended for sparkling white wine, some winemakers prefer to promote MLF to contribute to organoleptic complexity. Oenococcus oeni is generally the bacterium of choice for MLF.

People's interest in other species (such as Lactobacillus) is increasing, however, one disadvantage of lactobacilli is that they are more sensitive to low pH and SO₂, and some producers of starters inoculate high doses of non-growing bacteria in grape musts.

This work aimed to grow some selected strains of Lactobacillus in grape juice and perform early MLF. With this strategy, beyond performing the MLF homolactic bacteria can contribute clearly to maintain or even decrease the final pH in wines by producing lactic acid from sugars: they also produce more complex wines, and prevent the spoilage of an undesired late MLF in bottles. 

How were the Lactobacillus strains selected successively? Did all gradually adapt to low pH and SO₂ and achieve a complete MLF? Can this strategy help in biological acidification of wines against the loss of acidity derived from climate change?

Video of the seminar held during Enoforum Italia 2021 (18-20 May 2021)

Annual subscription to Infowine: The subscription, at a cost of € 60 (VAT included) entitles you to one year's access to all the documents published on the site, including the historical archive (click here).