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Transcript
High Alcohol Wines: How to Manage Primary and Secondary Fermentation Presented by: Jessica Just of Scott Laboratories and Sigrid Gertsen-Briand of Lallemand Winemaking Goals in a High Sugar Ferment • • • • • Convert all sugar to alcohol Minimize the production of volatile acidity Minimize volatile sulfur off-aromas Balance % alcohol with phenolic maturity Complete the malo-lactic conversion in a timely manner • Minimize microbial deviations Yeast Glucose CO2 Ethanol Esters H+ Internal pH is 5-6 H+ Glycerol Organic Acids Higher Alcohols Biomass (≈ 2% glucose) H+ H+ External pH is 3-4 >100-150 million CFU/mL Population Normal Fermentation Curve Higher yeast inoculation rate lowers dilution of the initial yeast cells survival factors 4-8 million CFU/mL million 2-42-4million CFU/mL CFU/mL Time Brix Survival factors are important to ensuring the proper working of the cellular membrane: poly-unsaturated fatty acids and sterols Key Interrelationships of Factors Affecting Fermentation SUGAR CONTENT TEMPERATURE CELL NUMBERS & HEALTH STRAIN SELECTION MAXIMUM FERMENTATION MANAGEMENT TOXIC FACTORS NUTRIENTS and OXYGEN COMPETITIVE FACTORS Temperature Control in Red Must Max. Temperature Cap • • • • • 20 Brix 21 Brix 22 Brix 23 Brix >24 Brix • • • • • 95°F 90°F 85°F 80°F 76°F What to Know Before Restarting a Stuck Alcoholic Fermentation • • • • Total residual sugar Glucose:Fructose ratio What caused the stuck fermentation Which yeast strain was used for the initial fermentation • Temperature control Dealing with a Stuck Alcoholic Fermentation • • • • • • Refer to websites for actual protocols Blend Sterile Filter Long acclimatization, build-up with sugar Short acclimatization with high inoculation rate How many times should you try to restart a stuck ferment? When can you start tasting the yeast? • Use of yeast hulls • Addition of nutrients? Alcohol content (% v/v) reached after fermentation in white wines with 56 selected Saccharomyces cerevisiae yeasts that were able to ferment all sugars. 12 11 Grado alcohólico adquirido (%) 10 9 8 7 6 5 4 3 2 1 0 Productor 1 Productor 2 Productor 3 Productor 4 Productor 5 Productor 6 Alcohol content (% v/v) reached after red vinifications with 35 selected Saccharomyces cerevisiae yeasts that were able to ferment all sugars. 18 17 16 15 14 Grado alcohólico adquirido (%) 13 12 11 10 9 8 7 6 5 4 3 2 1 0 B1 B2 B3 B4 C1 C2 D1 D2 D3 D4 D5 E1 E2 E3 E4 Productor 1 Productor 2 E5 E6 E7 E8 E9 E10 E11 E12 E13 E14 E15 E16 E17 E18 F1 Productor 3 Productor 4 Productor 5 Productor 6 F2 F3 G1 G2 G3 phosphoketoslase pathway (Heterofermentative) Citrate BACTERIA Acetate WINE Oxaloacetate L-Malate Mannoprotein L-lactate More efficient malic acid degradation 0.1-0.2 units increase in pH (palate) Pyruvate Diacetyl Polysaccharides b (1->3) glucanse Growth & stimulation of MLF Protein Bitterness ? flavour Sugar + flavour-aglycon Ethanol Increase in aroma Cell growth Citrulline, urea Ethyl Mousy Ethyl lactate compounds carbamate Off-flavour carcinogen Mouthfeel contribution Pentoses pentose phosphate pathway Sugaranthocyanin glycosidase (anthocyanase) Sugar + anthocyanidin Adsorption by cells Cell growth SO2-acetaldehyde Bruised apple (green, vegetative) Acetate & ethanol & free SO2 Glycerol & erythritol Mannitol Ethylesters esterase ethyl lactate, ethyl acetate, ethyl hexanoate, ethyl Colour reduction octanate b -glucosidase Peptides Esters synthesis & hydrolysis Sucrose, trehalose phenolic glucosides Glycoside (flavour) protease Embden-MeyerhofParnas pathway (Homofermentative) Glucose Lactate Fructose Trehalose & disaccharide acetate Aspartate Pyruvate Polyols Monosaccharides Mouthfeel & body Fatty acids contribution & Lipids D-lactate Glucose Fructose Buttery, nutty aroma/flavour Phenols (gallic acid & anthocyananins) Hexoses Lipids lipase Volatile fatty acids Fruity aroma Oak products Hydrolase ? furfural Phenolic acids p-coumaric acid Biogenic amine production 4-ethyl guaiacol histamine & 4-ethyl phenol tyramine Spicy, clove sweaty, bandaid Copper ions Inhibitory to growth Eveline Bartowski, AWRI, 2004 Key Interrelationships of Factors Affecting ML Fermentation ALCOHOL CONTENT TEMPERATURE CELL NUMBERS & HEALTH TOXIC FACTORS STRAIN SELECTION NUTRITIONAL FACTORS COMPETITIVE FACTORS INTERACTION OF PARAMETERS bacteria 10x volume of water 20 MINUTES + 10x volume of wine pH > 3.5 After 18 – 24 h Final wine volume Conclusion • • • • • • Proper inoculation rate Strain selection Proper Rehydration Temperature Control Balanced nutrient (and oxygen) additions Timing of additions Thank you! • For more information on any of these HUGE topics… please contact: – Jessica Just ([email protected]) – Sigrid G-B ([email protected])
