New strategies to manage the acidity of Syrah wines. Use of non-Saccharomyces yeasts

Abstract

Due to climate change, there is an increase of temperatures and the rainfall distribution is changing over the course of the year. These changes help to accelerate grape ripening, providing musts with high sugar concentration, low acid content and high pH. As a result, wines are excessively warm and sensorially not very expressive. The use of Lachancea thermotolerans strains is a biological alternative that increases acidity and aromatic compounds, improving the sensorial profile of wines. In this paper, the influence of a specific L. thermotolerans strain, Laktia™ (Lallemand Inc.), in the production of Syrah wines during two consecutive harvests is discussed. Trials were carried out in an experimental cellar. Alcoholic fermentation was induced by sequential inoculation of Laktia™ and two Saccharomyces cerevisiae strains, and malolactic fermentation was induced in two ways: sequential and simultaneously to alcoholic fermentation. Our results show the contribution of Laktia™ to the natural acidification of wines by producing L-lactic acid, just as other authors have described for other L. thermotolerans strains. The wines obtained also have a slightly lower alcoholic degree, a slightly higher glycerol content and, in some cases, a sensory profile that is better valued in comparison to those from control vinifications with chemical acidification. Simultaneous induction of alcoholic and malolactic fermentation was the best option to avoid delay in malolactic fermentation.