Saturday, October 5, 2013

How to Prevent Premox in White Wines

My husband recently sent me this link: FERMENTATION KEY TO PREMOX BATTLE, an article that appeared in the drinks business on September 26, 2013.
Since we will be making Chardonnay, I was interested in what Professor Denis Dubourdieu and Dr. Valérie Lavigne had to say about how to prevent premature oxidation. Based on their research, Dr. Lavigne listed seven key moments in the winemaking process when grapes can become especially susceptible to oxidation:
  • In the vineyard, the lack of nitrogen diminishes plant vigour and diminishes the levels of glutathione in grapes, a compound which protects against oxidation
  • During pressing, limit the extraction of phenolic compounds since excessive levels will lower the amount of glutathione in the juice
  • During fermentation, the must should not be too clean or the fermentation will be too slow or incomplete leading to the loss of reductive qualities
  • During fermentation, ensure that only a short period elapses between alcoholic and malolactic fermentation, a critical time when the wine is not protected by carbon dioxide or sulfur dioxide
  • During barrel aging, battonage helps to create a more reductive atmosphere
  • During barrel aging, it is important to protect the wine with inert gas and sulphur dioxide
  • During bottling, limit the wine’s exposure to oxygen
In summary, Professor Denis Dubourdieu and Dr. Valérie Lavigne advised that Chardonnay grapes should be pressed at a low temperature and the fermentation should be fast and complete within two weeks.

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