Introduction of the Brettanomyces Impact Wheel Lucy Joseph Department 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

Strain Collection

Initial Screen Defined medium was used Supplemented with amino acids All strains will make 4EP and 4EG with coumaric and ferulic acids

Initial Screen

Correlation of Descriptors with Intensity and Like/Dislike scores

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”

Positive and Negative Perception

Summary of Aroma for Strains Tested in Wine

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

Strains – Aroma Compounds

Acknowledgements Beth Albino Bisson Lab