Fermentation Practices

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Fermentation Practices

• Fermentation Variables
• And
• Their Control

By Finn B. Knudsen Beverage Consult
International, Inc. Evergreen, Colorado
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Open Fermentation Vesselin the early 1900s
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Outdoor Uni-Tanks
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Outdoor Uni-Tanks - Piping
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Variables in Fermentation

• Fermentation Time
• Attenuation
• Flavor Profile
• Yeast Crop
• Yeast Suspension Flocculation
• Foam Development

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Factors AffectingFermentation Variables

• Chemical Biochemical Factors
• Wort Constituents
• (almost fixed)
• Microbiological Factors
• Yeast
• (controllable factors)
• Physical Factors
• Environment
• (controllable factors)

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Controllable Factors AffectingFermentation
Variables

• Microbiological Factors
• Yeast Strain and Purity
• Yeast Handling and Propagation
• Yeast Pitching
• Yeast Viability, Suspension/Flocculation and Crop
• Contamination

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Controllable Factors AffectingFermentation
Variables

• Physical Factors
• Temperature
• Pressure
• Agitation

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Traditional Yeast Quality Guidelinesused in a
brewery

• Microbiological Purity (Bacteria, Wild Yeast).
• Viable Cell Counts
• Cell size and Uniformity
• Yeast Biochemistry
• Fermentability and Flavor Profiles
• Yeast Suspensions and Flocculation Patterns

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Yeast Propagation Facilityin the early 1900s
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Propagation procedure

• Since Emil Chr. Hansen isolated a single yeast
  cell at Carlsberg Laboratories in 1881 -
  propagation has begun in the laboratory.
• Last step before the propagation plant is the
  Carlsberg or Hansen Flask.
• In the Carlsberg Flask wort can be sterilised,
  inoculated and trasferred out again under sterile
  conditions.

Carlsberg Flask
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Yeast Propagation Facilityin the early 2000s
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(No Transcript)
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Yeast Filter Press
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Factors influencingYeast in a Storage/Holding
Tank

• Storage Duration
• Temperature
• Agitation, Impeller Speed and design,
• and/or Recirculation
• Vessel Design and Size

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Single or multiple vessel plants

• Batch production in a single vessel YPP
• Continuous production in a multiple vessel YPP
• Choise depends on propagation philisophy,
  frequency and investment
• Cell counts are typically, respectively 100-150
  and 50-100 million/ml

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Yeast Storage/Holding Vessels
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Various Fermenter Designs
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Various Agitated Fermenter Designs
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Hydraulics within a Vertical Fermenter