Managing Alcohol Fermentation Good Fermentation Practices Michigan Wine & Grape Conference, Grand Rapids February 24, 2010 Gordon Specht
Development and production of Yeast Bacteria and their derivatives
How to keep the yeast happy and minimize risks Good Fermentation Practices (GFP)
If Good Fermentation Practices are used... Sugar if not...higher risk of sluggish or stuck alcohol fermentation finish and... Fermentation Time
Factors affecting Fermentation Management - Key Interrelationships JUICE or MUST TEMPERATURE YEAST STRAIN CELL NUMBERS & HEALTH OPTIMUM FERMENTATION MANAGEMENT NUTRITIONAL FACTORS TOXIC FACTORS COMPETITIVE FACTORS
4 phases of Alcohol Fermentation Stationary Yeast Population Exponential Growth Decline 2-4 million Lag Fermentation time
In the winery Good Fermentation Practices should be used during >100-150 million 2-4 million 2-4 million Fermentation time
In the winery Good Fermentation Practices should be used during yeast rehydration >100-150 million 2-4 million 2-4 million Fermentation time
Good Fermentation Practice (GFP) at yeast rehydration stage: Proper Yeast Rehydration & Handling Addition of micronutrients Directly feed selected yeast with balance of key vitamins and minerals Why? They won t be used by ambient microbes or bound by must components Helps yeast population and health
Yeast Viability 80 70 60 50 40 30 20 10 0 Viability: 70% = 49 x 10 6 live cells Viability: 43% = 23 x 10 6 live cells Control 18 C Goferm 18 C 0 200 400 Hours Similar results at 24 C and 28 C, there is a strong positive effect on yeast viability when yeast stimulant GoFerm (minerals and Vitamins) added during yeast rehydration.
4 Easy Steps for Rehydrating Yeast and Inoculating Juice or Must
4 Easy Steps for Rehydrating Yeast and Inoculating Juice or Must
4 Easy Steps for Rehydrating Yeast and Inoculating Juice or Must
4 Easy Steps for Rehydrating Yeast and Inoculating Juice or Must
>100-150 million In the winery Good Fermentation Practices should be used during the beginning of yeast fermentation 2-4 million 2-4 million Fermentation time
GFP at beginning of fermentation: red musts If needed addition of complex nutrients at the end of yeast lag phase Under medium or low Yeast Available Nitrogen Conditions (YANC) Nitrogen as ammonia and alphaamino acids Additional survival factors sterols and unsaturated fatty acids Addition of oxygen as soon as the cap is formed (usually 15 g/l sugar fermented)
GFP at beginning of fermentation: red musts If needed addition of complex nutrients at the end of yeast lag phase Under medium or low Yeast Available Nitrogen Conditions (YANC) Nitrogen as ammonia and alphaamino acids Additional survival factors sterols and unsaturated fatty acids Addition of oxygen as soon as the cap is formed (usually 15 g/l sugar fermented)
>100-150 million In the winery Good Fermentation Practices should be used during the yeast exponential growth phase 2-4 million 2-4 million Fermentation time
GFP at yeast exponential growth phase Speed of yeast multiplication during growth phase
Don t grow yeast up too fast temperature management Low alcohol concentration High alcohol concentration Slow alcohol excretion
In the winery Good Fermentation Practices should be used during 1/3 1/2 through fermentation >100-150 million 2-4 million 2-4 million Fermentation time
GFP ~1/3 rd through the fermentation: red must If needed addition of complex nutrients at ~1/3 rd through the ferment under medium or low YANC Nitrogen as ammonia and alphaamino acids Additional survival factors sterols and unsaturated fatty acids Oxygen addition at one third of sugar depletion
GFP during peak of fermentation: red musts Maximum temperature reached under the cap Cap during the fermentation Fermenting Juice Yeast Biomass
In the winery Good Fermentation Practices should be used during the last ¼ of fermentation >100-150 million 2-4 million 2-4 million Fermentation time
GFP during the last quarter of fermentation: red musts Regular movement of the yeast during their death phase Deep punching down Bring the yeasts back up into suspension
Move your yeasts! Delestage Complete draining of fermenter O 2
GFP : whites Osmotic shock on the yeast Yeast cell content of stress resistant factors Addition of fatty acids, sterols, vitamins, amino acids and micronutrients at the inoculation step Temperature shock in cold juices Grape juice solids (pectic flakes) Oxygen addition as soon as the fermentation is active (usually 15 g/l sugar fermented) Oxygen addition at one third of sugar depletion Addition of ammonia at one third of sugar depletion Addition of fatty acids, sterols and alpha-amino acids at one third of sugar depletion Low temperature during the yeast death phase Regular movement of the yeast during their death phase
4 Easy Steps for Rehydrating Yeast and Inoculating Juice or Must
What are pectic flakes? After a cold settling with pectic enzymes Clear juice Pectic flakes Heavy solids
Special constraints : be even more careful applying GFP Large tanks (>25,000 gal.) or tall & narrow tanks : an important consideration Uncertain hygiene in the cellar End of harvest Other unknowns : personnel experience, training, knowledge of procedures, etc.
Good Fermentation Practices (GFP) Risk Management Very critical above ph 3.5! LYSOZYME Selected Yeast Viable Cells (cfu/ml) 10 8 10 7 10 6 10 5 10 4 10 3 10 2 10 SO 2 Gluconobacter Lactobacillus Pediococcus SO 2 Acetobacter spontaneous Oenococcus Further Microbial control as needed HARVEST TRANSPORT AF AGEING
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