Enoforum 2021
IVES 9 IVES Conference Series 9 Enoforum Web 9 Enoforum Web Conference 2021 9 Cellar session 9 Adaptation of Lactobacilli towards low ph and SO2 to develop MLF in base musts for sparkling wines

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

Abstract

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. However, 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 aims 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. 

To perform this selection, twelve Lactobacillus strains were successively inoculated after adapting to the lowering of pH and the increasing concentration of SO2. The cell concentration of the inoculum was in the order of x 106 CFU/mL to allow growth and synthesis of lactic acid. All Lactobacillus strains gradually adapted to low pH and SO2 and could grow at pH 3.2 and the highest SO2 concentration, thereby maintaining or even increasing their final biomass. After 7 days, all strains always underwent MLF. Malic acid consumption rate and lactic acid production depend on the strain. The final pH of wines was maintained or even decreased, even when complete MLF was achieved. This strategy helps in biological acidification of wines against the loss of acidity derived from climate change.

DOI:

Publication date: April 23, 2021

Issue: Enoforum 2021

Type: Article

Authors

FERRER Sergi, POLO Lucía, ANDRÉS Lorena, PARDO Isabel

Institut de Biotecnologia i Biomedicina (BioTecMed), Universitat de València, Spain

Contact the author

Tags

Enoforum 2021 | IVES Conference Series

Citation

Related articles…

Measurement of grape vine growth for model evaluation

Within a research project for simulating the nitrogen turnover in vineyard soils and the nitrogen uptake by the grape vine, a previously developed plant growth model (Nendel and Kersebaum 2004) had to be evaluated. A dataset was obtained from a monitoring experiment at three vineyard sites with different soil types, conducted in the years 2003 and 2004.

Mechanisms involved in the heating of the environment by the aerodynamic action of a wind machine to protect a vineyard against spring frost

One of the main consequences of global warming is the rise of the mean temperature. Thus, the heat summation by the plants begins sooner in the early spring, and by cumulating growing degree-days, phenological development tends to happen earlier. However, spring frost is still a recurrent phenomenon causing serious damages to buds and therefore, threatening the harvests of the winegrowers. The wind machine is a solution to protect fruit crops against spring frost that is increasingly used. It is composed of a 10-m mast with a blowing fan at its peak. By tapping into the strength of the nocturnal thermal inversion, it sweeps the crop by propelling warm air above to the ground. Thus, stratification is momentarily suppressed. Furthermore, the continuous action of the machine, alone or in synergy, or the addition of a heater allow the bud to be bathed in a warmer environment. Also, the punctual action of the tower’s warm gust reaches the bud directly at each rotation period. All these actions allow the bud to continuously warm up, but with different intensities and over a different period. Although there is evidence of the effectiveness of the wind machines, the thermal transfers involved in those mechanisms raise questions about their true nature. Field measurements based on ultrasonic anemometers and fast responding thermocouples complemented by laboratory measurements on a reduced scale model allow to characterize both the airflow produced by the wind machine and the local temperature in its vicinity. Those experiments were realized in the vineyard of Quincy, in the framework of the SICTAG project. In the future paper, we will detail the aeraulic characterization of the wind machine and the thermal effects resulting from it and we will focus on how the wind machine warms up the local atmosphere and enables to reduce the freezing risk.

AOC valorization of terroir nuances at plot scale in Burgundy

In the highly competitive global wine market, Burgundy has a long-established reputation to maintain. The vine and wine sector in Burgundy is based on a five-level ranking of AOC (Appellation d’Origine Contrôlée) wines and of the plots where the grapes are grown.

Using GIS to assess the terroir potential of an Oregon viticultural region

Deciding to grow grapes in Oregon is complex issue due to our diverse geography, climate, and relatively short history of grape growing. For any potential grape grower, vineyard site selection is the single most important decision they will face.

Classification of “Valpolicella Superiore” wines in relation to aromatic composition: influence of geographical origin, vintage and aging

The Valpolicella appellation, mainly known for Amarone and Ripasso, is experiencing growing interest in Valpolicella Superiore (VS), a lighter red wine aligning with consumer demand. However, anecdotal evidence suggests different stylistic interpretations of VS, potentially causing consumer confusion.