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

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