Wine process

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The main objectives of this study were to decrease wine alcohol content by combining several techniques, from the vineyard to the cellar.

The combination of these techniques should allow to decrease alcohol in wine by 2% in volume.
A two-years trial was focused on two main cultivars of the south-west of France vineyard: Tannat N and Gros Manseng B. By now, in the context of climate changing, the grapes often raise a high level of sugars, up to or more than 15 % of potential alcohol.

In the need to delay ripening and create more digest wines, three cultural techniques were tested and compared to a control:

  • leaf removal on the upper part of the canopy,
  • reduced canopy by late hedging
  • and anti-transpirant spraying on the full canopy.

Those techniques were combined with a biological process to reduce alcohol production using yeast with a low alcoholic yield. Four replicates were vinified with both low yield yeast of Saccharomyces Cerevisiae and control yeast.

Results showed that late hedging was the most efficient to reduce ripening on both cultivars but had also an impact on other parameters such as acidity and polyphenols.

The other viticultural techniques assessed also showed efficiency in reducing ripening.
During winemaking, low alcoholic yield yeast leads to lower alcohol content with more acid wines and lower volatile acidity content.

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