BRETTANOMYCES
Identification
Smell
barnyard
horse
mouse
band-aid
Place of occurrence
winery
Cause of occurrence
Brettanomyces is a genus of yeasts that is ubiquitous in the natural environment. When they enter the wine, microbiological processes begin, leading to the appearance of unpleasant odours. This problem is mainly found in red wines aged in oak barrels. One of the by-products of Brettanomyces activities are volatile phenols, namely 4-ethylphenol and 4-ethylguaiacol. 4-ethylphenol is the source of the most unpleasant odours in wine. The common sensory threshold for 4-ethylphenol is 425 μg/L. The defect can also develop and exceed the sensory threshold after bottling wine in consumer packaging
Counteraction
Use of higher doses of sulphur dioxide (SO2) (within the legal limits) during wine production
Regular sediment removal from wine during ageing in vats and/or barrels
Use of chitosan during wine production
Use of the product Velcorin (dimethyldicarbonate (C4H6O5)) before bottling wine in consumer containers
Reduced contact of wine with oxygen (O2) during ageing in oak barrels
Maintaining the proper level of hygiene of the winemaking equipment and winery
Sterile filtration
Thermal treatment of wine