Population dynamics and effects of Brettanomyces bruxellensis strains on Pinot noir (Vitis vinifera L.) wines
Replicated, sterile Pinot noir (Vitis vinifera L.) wines were individually inoculated with one of six strains of Brettanomyces bruxellensis (Ave, M, 216, Vin 1, Vin 4, or Vin 5) at initial numbers < 50 cfu/mL. In two separate studies, population changes were monitored for 23 months, or until cell densities peaked and subsequently declined to less than or equal to 30 cfu/mL. Significant variation was noted in both growth rate and stationary phase population densities among strains. The concentration of selected volatile components was monitored using solid-phase microextraction GC/MS. Large increases in the concentration of 4-ethylphenol occurred after titers reached 2.5 x 10(5) cfu/mL. Brettanomyces-inoculated wines were found to have detectable concentrations of ethyldecanoate, isoamyl alcohol, 4-ethylguaiacol, and 4-ethylphenol, with some significant differences in their concentrations among strains. Duo-trio testing suggested sensory differences between the control and all inoculated wines and among wines inoculated with strains Ave and Vin 5, M and 216, and M and Vin 4. Consensus training analysis suggested that all Brettanomyces wines had a greater perception of earthy, smoky, spicy, and cardboard descriptors than uninoculated control wines.