Utilizing malolactic fermentation as a tool to prevent Brettanomyces bruxellensis wine spoilage
Brettanomyces bruxellensis is considered one of the most problematic wine spoilage yeasts due to the difficulty of controlling it, the potential significant financial losses due to loss of wine quality, and the cost of prevention and remediation measures. Wine is particularly vulnerable to B. bruxellensis infection during and shortly after the malolactic fermentation (MLF) as SO2 cannot be added until this process is complete. It has been suggested that conducting a rapid MLF initiated by inoculation of Oenococcus oeni is a useful strategy to prevent B. bruxellensis spoilage as this minimizes the length of time the wine is not protected by SO2. This project investigates an additional benefit of conducting a rapid MLF, the prevention of B. bruxellensis growth due to inhibitory interactions with O. oeni. Pinot noir wine (no SO2 additions, no MLF) was produced and used to test the ability of a number of commercial O. oeni strains to inhibit B. bruxellensis growth at the end of MLF. Sterile filtered wine was inoculated with various O. oeni strains and growth and malic acid monitored. When MLF is complete, wines will be inoculated with a select strain of B. bruxellensis and growth and volatile phenol production monitored.
The sensitivity of a number of B. bruxellensis strains to O. oeni is also being determined. B. bruxellensis strains have been sourced representing B. bruxellensis isolates from a wide range of winemaking regions including Oregon. A model wine system was identified for use to improve the rate that B. bruxellensis strains can be tested for inhibition by O. oeni. Results from the model wine system will be used to select which strains will be used in wine experiments that take significantly longer to complete.