Introduction of the Brettanomyces Impact Wheel
Lucy JosephDepartment of Viticulture and Enology
U.C. Davis
Introduction
• Brettanomyces is considered to be the primary spoilage yeast in finished wine
• However, many consumers and critics like the complexity that is derived from Brett growth in wine
• What accounts for that complexity?
Compounds Produced by Brett in Wine
• Signature spoilage compounds - ethyl phenols, vinyl phenols
• Other spoilage compounds – acetic acid, ethyl acetate, fatty acid, carboxylic acid
• Compounds that are positive – Esters, higher alcohols, terpenes
Initial Screen
• Defined medium was used• Supplemented with amino acids• All strains will make 4EP and 4EG
with coumaric and ferulic acids
Selection for Test in Wine
• Descriptors, intensity, and likability used to score strains
• Out of the initial 83 that were successfully screened in the initial screen, 17 were chosen as “positive” and 5 as “negative”
SPME-GCMS
• These strains were also screened chemically• Used defined medium supplemented with – Aromatic amino acids– Cinnamic acids and aromatic amino acids
• Goal was to identify strains that produced low negative characters