Yeast Laboratory Basics
Inland Island Yeast Laboratories
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Established in 2014 to serve Denver
Work with 60+ local brewers
30,000 servings of beer a day with INIS Yeast
John Giarratano, MS BioEngineering
– Pharma and Biofuel
• Matthew Peetz, MS Cell Biology
– Biochemistry, Yeast Propagation, Biofuel
Yeast Basics
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“Brewers make wort, yeast makes beer”
Single Celled Fungi
Evolved on Fruit
Make-Accumulate-Consume
– Produce Ethanol as a food reserve
– Crabtree Effect
• Reproduce by budding
• 46.3% CO2, 48.4% EtOH, 5.3% Cell Mass
• <1% esters, phenols, aldehydes, ketones, acids,
etc.
Fine Tuning Byproduct Production
Increasing
Esterification
Ester
Fusel Alcohol
Original Gravity
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FAN (High or Low)
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Lipids
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pH
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Aeration
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Zinc
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Temperature
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Agitation / Stiring
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Head Pressure
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Multiple Ferm Fills
(Non-Aerated Wort)
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Multiple Ferm Fills
(Aerated Wort)
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Pitching Rate
Laere, et al., 2008
Where Do Breweries Get Yeast?
• Yeast Supplier / Laboratory
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Other Breweries
Dry Yeast
House Strain
Prop Your Own
Cell Count / $
Sterility & Health
Variety & Quality
Variety
Time, Cost & Space
Importance of Pitch Rate
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750,000 Cells/mL/°Plato for Lab Grown Cells
1 Million Cells/mL /°Plato for Repitch
1.2 - 1.5 Million for High Gravity
Add 30-50% for Lagers
Fermentation Issues with Under Pitching
Longer Fermentation time
Lags
Stall Out
Higher Ester Formation
Lower Viability for Repitch
How to Pick the Best Strain?
• Style
– Belgians, English, Lagers, etc…
• Brewery Capabilities
– Temp Control
– Yeast Management
# Strains = # Brew Days / 3
• Attenuation/Gravity
• Blends
Yeast QA/QC
• Cell Count
• Viability vs Vitality
Lactic Acid (>0.8% w/v)
– Viability <80%
Sodium
500 ppm
• Yeast Stress
– Synergistic
pH (3 ish)
Ethanol 20%
Temperature (85 F)
Acetic Acid (>0.05% w/v)
Cell Counting
Method
Hemocytometer
Spectrophotometer
Automated Counter
Positives
High Accuracy
High Precision
Viability
Easy to use
Fast
Affordable
High Accuracy
High Precision
Fast
Negatives
Requires Training
Low Precision
Background Adjustment
No Viability Measurement
Cost
Specialized equipment
Selective Media
• Plating of samples
• Selective media
– LWYM
• Wild Sacch
– LCSM
• Non-Sacch Yeast
– WLD or LMDA
• Brewery Bacteria
– WA
• Yeast
– HLP
• Lacto and Pedio
Storage and Maintenance
• Storage Vessel
– Low pressure (PSI 20) under low alcohol beer
• Shelf Life
– 1-2 weeks, afterwards test it
• Revitalizing
– 20 P at 1:20 v/v, hold ~6 hours
• Washing
– 20-50 ppm sodium chlorite (5 Star or Birko)
Setting Up a Basic Yeast Lab
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Microscope
Slides
Hemocytometer
Pipette
Tubes
Loop
Burner
Incubator
Autoclave
Methods
What is Realistic?
• Novice
• Microscope, Slides, Hemocytometer, Pipette
• Intermediate
• Novice + Tubes, Loop, Burner, Incubator
• Skilled
• Intermediate + Autoclave, Plates
• Pro
• Intermediate + Laminar Flow Hood, -80°C Freezer
<$500
<$800
$2,000$10,000
$20,000+
Yeast Laboratory Basics
QUESTIONS?
[email protected]