The Brettanomyces/Dekkera genus of yeasts has the ability, in a practically exclusive manner, to form considerable quantities of ethyl-phenols in wine, thus giving rise to what is known as "phenolic odours". Besides, on finishing the fermentations, wines contain an average of at least 400 mg/l of residual sugars fermentable by Brettanomyces and which, theoretically, enable the formation of 600µg/l of ethyl-phenols.

lassical analysis has been to analyse the presence of these yeasts through microbiological cultures, giving poor results due to the response time. In this sense, advances have been made with the development of the ELISA and PCR methods, but without obtaining the expected results.

Tecnalia te+C have put into operation a method that enables the analysis of these volatile phenols using the Mass Chromatography. The technique developed involves extraction on micro fibre and subsequent injection into the chromatograph, resulting in the detecting of very low µg/l levels of these phenols.

Knowledge of increases of these values helps the enologists in their fight against contamination by and proliferation of Brettanomyces, thus enabling the control of the presence of these yeasts, adopting enological practices necessary to stabilise the product.

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