Transcript Introduction to 2011 Student ML Trial

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