Malolactic fermentation (MLF) is often difficult to achieve in wines with high acidity, therefore the development of strategies to favour biological deacidification and aroma improvement of low pH wines is important.
It was clear from our screening of strains for performing at low pH that it is highly strain specific and that it is directly correlated to cell numbers.
Results using a Chardonnay with a pH 3.2 and malic acid level of 4.3 indicated the pairing of yeast and bacterial strains for low pH and high malic conditions is crucial to ensure firstly successful MLF and secondly it also influences the aroma potential of the MLF strains, especially esters even if MLF was partial.
Results obtained showed that Oenococcus oeni performed better than Lactobacillus plantarum as they attained there cell numbers at higher levels during the fermentation.
The impact of different MLF inoculation strategies with two different O. oeni strains on cool climate Riesling wines (pH 2.9-3.1) and the volatile wine aroma profile was investigated.
In another study using Riesling and Chardonnay simulatin cool and warm climate conditions it was shown that low pH (3.2) and high alcohol (15% v/v) conditions was the most difficult MLF scenario but that even partial MLF under these conditions had an impact on the aroma profile of the final wine, specifically esters. Results also highlighted that certain terpenes was produced at higher levels at pH 3.2 than 3.8.
Article based on the paper presented at the “International Cool Climate Wine Symposium”, ICCWS, Brighton, England, 26-28 may 2016