Dekkera

Dekkera is a genus of yeast fungi in the class Saccharomycetes, the sexual stage of the Brettanomyces yeasts. Its best-known members, Dekkera bruxellensis and D. anomala, spoil beer and wines by generating barnyard, medicinal and smoky notes from volatile phenols that can ruin whole cellars. A tiny surviving population is enough to taint barrels of red wine, so control leans on sanitation, sulphur dioxide management and filtration. Paradoxically, the same organisms lend prized funky complexity to Belgian lambics and farmhouse ales when deliberately managed.