Comparative studies on the dynamics of fermentation of selected wine yeasts

Aim: The aim of this work is educating people about soil variability, vine rootzone depth and readily available water holding capacity. The concept of terroir is readily discussed in the wine industry but many people involved are unable to describe a soil profile and interpret its limitations that impact on vine growth, fruit quality and wine produced. This paper discusses soil physical characteristics important to vine root growth and readily available water holding capacity (RAW).

The wide diffusion of organic cultivation of vineyards and the need to reduce the use of pesticides highlights the urgent need for alternative and sustainable methods of vine protection by pathogen molds.

The exploitation of secondary metabolic pathways of non-Saccharomyces yeasts is a promising approach to protect traditional wines from the ongoing climate change, which can alter their peculiar features by modifying the chemical composition of grape musts. In this regard, an interesting example is the sequential inoculum of Lachancea thermotolerans and Saccharomyces. Cerevisiae. The aim of the sequential inoculum is to increase titratable acidity by lactic acid accumulation, to lower pH and to reduce the alcohol and acetic acid content in wine.

Copper (Cu) is known to substantially impact wine stability through oxidative, reductive or colloidal phenomena. Recent work has shown that Cu exists predominantly in a sulfide-bound form, which may act as a potential source of sulfidic off-odours in wine and hence contribute to reductive flavours

In the Cognac region in France, Ugni blanc is the most planted grape variety (98% of the 80 500 ha). This vine region is in expansion due to the success of the associated well-known brandy and the need of high grape yield to guarrantee the production of base wine for distillation. About 2 to 3000 ha are newly planted each year and rootstocks are one powerfull tool for vineyard adaptation to soil or climate change. As rootstocks ensure water and mineral nutrient supplies to the scion, it is important to better understand their effect on berry compostionnal parameters such as sugars and nitrogen compounds, which are the main precursors for fermentary aroma metabolites, the latter being quality markers for Cognac after distillation.