Influence of oak origin and ageing conditions on wine spoilage by Brettanomyces yeasts

The use of oak wood is a common practice for the maturation of higher quality wines, but this practice also has been occasionally related with the spoilage of wines with ethylphenols produced by Brettanomyces/Dekkera yeasts. This work studied the presence of these yeasts and ethylphenol production in the same wine aged in different conditions: aerobic/anaerobic, sulfur dioxide additions, and oak origin of the casks used (American, French, Russian and Chinese), with the aim of characterizing factors affecting the development and production of volatile phenols by Brettanomyces. Results obtained indicated the spoilage risk exists when Brettanomyces cells are present, even at a low level, in wines subjected to ageing, both in the cask and the bottle. Brettanomyces presence (cfu/ml and strains) and ethylphenol production during ageing, is affected more by the ageing conditions (aerobic/anaerobic and sulfiting) than by the origin of the oak.