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Introduction to 2011 Student ML Trial. Linda F. Bisson Wine Flavor 101B March 23, 2012. The Malolactic Fermentation. Provides microbial stability to wine Impacts wine flavor and aroma. Goals of Trial. Does the timing of addition of the ML inoculation impact success?
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Introduction to 2011 Student ML Trial Linda F. Bisson Wine Flavor 101B March 23, 2012
The Malolactic Fermentation • Provides microbial stability to wine • Impacts wine flavor and aroma
Goals of Trial • Does the timing of addition of the ML inoculation impact success? • Does the ML strain make a difference?
Timing of Addition • If add early, bacteria can take advantage of nutrients like glucose and fructose. • If add early, bacteria may inhibit yeast metabolism and fermentation • If add early, yeast may inhibit bacteria • If add late, conditions will be more hostile to bacteria
Timing of Addition • There is no one correct answer • ML and yeast strain dependent • Influenced by juice composition
Strain Differences • Metabolite profile is strain dependent • Ability to persist in a marginal environment is strain dependent
The Experiment • Used Chardonnay Juice (pH 3.6; 22.4 Brix; TA: 5.76 g) • Cold settled, 72 hours, 2°C, racked, Nitrogen blanked stored at 2°C until used • Inoculated withEC1118 • No Sulfite before or during experiment • ML inoculated at three different times: • Simultaneous with yeast • During late fermentation • Post-fermentation
ML Strains Evaluated • Alpha • VP41 • 31 • Native ML
Conclusions • Fastest ML completion rates were noticed with juice inoculation • Timing of inoculation did not impact success of ML completion • Strain differences were noted, also in initial sensory experiments • The control ML underwent ML in about two months.
ML Tasting • Glass 1: Alpha, pre-fermentation • Glass 2: Alpha, mid-fermentation • Glass 3: Alpha, post-fermentation • Glass 4: VP41, post-fermentation • Glass 5: 31, post-fermentation • Glass 6: Control spontaneous ML