scandi brew yeast propagation & storage by mike cholerton sales & technology manager...

Scandi Brew

Yeast Propagation & Storage

ByMike CholertonSales & Technology ManagerScandi-Brew Alfa Laval Copenhagen A/Swww.alfalaval.com

MBAA-Rocky Mountain District MeetingMarch 24, 2004

© Alfa Laval Slide 2 www.alfalaval.com

Yeast Propagation & Storage


• History goes back to 1901 as APH

• Today the world’s leading supplier of yeast handling equipment and tank top systems

• Supplied worldwide during the past 10 years:

– 130 Yeast propagation plants

– 42 Yeast storage plants

– 500 Yeast mixers

• Since 1999 member of the Alfa Laval Group handling all “Yeast+” activities

Scandi Brew


Yeast Management ???

Rules and procedures for handling yeast in the brewery

• Ensures fresh supply of yeast

• In general healthy and productive yeast

• Discharge of old and infected yeast


• Propagation of fresh yeast

• Control infection

• Cold storage

• Homogenisation

• Low mechanical stress (pumps, mixing)

• Low environmental stress (pressure, CO2)

• Avoid contact with O2 unless the yeast is cold

• Reduce CO2-content during storage

Key words

Yeast Management


Why Yeast Propagation?

To control beer quality propagation and thereby fresh yeast supply is necessary

• In the fermentation process yeast mutates and change performance over time - as well as infection sooner or later becomes a problem


• Slow fermentation

• Slow pH-drop causing infections to flourish

• Slower rates of maltose & maltriose uptake

• Higher level of SO2 and H2S

• Prolonged diacetyl removal during maturation

• Changed flocculation characteristics

Fermentation problems with old yeast


• Producing - from a single cell - sufficient amount of yeast for fermenting a batch (brew or fermenter size) of wort

• The yeast should be 100% uninfected

• The yeast should be propagated with effective aeration in order to achieve a sufficient cell count

Yeast Propagation


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 Flask.

In the CF wort can be sterilised, inoculated and trasferred out again under sterile conditions.

Carlsberg Flask


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

• Difference in laboratory work


• High temperature will give fast propagation

• But also cause stronger flavour impact from the propagated yeast

Temperature

Propagation parameters


• The more effective the aeration - the higher the cell count

• Continuous

• By interval

• Flow rate

• Foam problems

Aeration



• From sterile to sterile conditions 1:100 (1:200)

• From sterile to wold wort conditions 1:10 (1:20)

Propagation Step



• Separate heating & cooling jackets on all vessels

• In-vessel sterilisation of wort making a separate steriliser superfluous

• All process and sterile air pipes and valves are easily cleanable and designed for steam sterilisation

• Special designed aeration lance - fully integrated in the CIP and sterilisation system

Special features of SCANDI BREW® plant

Yeast Propagation Plant


• Special outlet valve with no dead space

• Remote controlled pressure regulation

• 100% headspace in 1-vessel plant, 40% in multiple vessel plant

• Unique top plate design - 100% CIP’able

• Sterilisable yeast mixer / CIP system for improved plant efficiency

• Multi-purpose vessel design as yeast storage vessel

Special features of SCANDI BREW® plant




Propagation and all transfers are under sterile conditions

All pipes, valves & sterile air supply is 100% sanitary

SCANDI BREW® plant


To protect and improve yeast viability and vitality during storage

Yeast Storage


Yeast Storage

• Harvest asap

• Dispose of old & infected yeast

• Yeast is cooled fast

• Shorten storage time

• Homogenise the yeast

• Reduce pressure

• De-gassed if possible

• Avoid shear stress

• Avoid infection


Yeast storage plant


• Gives flexibility in harvest and pitching

• Possible to evaluate yeast before re-use

• Homogenisation possible giving accurate pitching

• Cold storage keeps metabolism and autolysis to a minimum

• De-gassing increases viability

• Offers the possibility of aeration prior to pitching

• Storing in the cone of a CCF can be avoided

Purpose of a specialised YSP


Yeast Mixing

SCANDI BREW® off centre mixer

Off centre or centre

• Yeast mixer / CIP system

– with aeration or acid washing facility


Yeast Mixing

Off centre versus centre• Fully CIP’able

• Acid washing & aeration

• Effective mixing & gentle handling

• Up to 50% solids

• Above 50% solids

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Off centre Centre

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Off centre

• Function

Yeast Mixing


Yeast Mixing

Flow-turbulence characteristics

• Gentle product handling


Centre

• Function

Yeast Mixing


• Hollow shaft

• Self cleaning

• Fully CIP’able including bottom support

• Aeration and acid wash possibility

• Intermittent operation

Centre

Yeast Mixing


Yeast Pumping

Gentle transfer of yeast to avoid mechanical stress with a sanitary and dedicated yeast pump


• Setting up standards for yeast handling and yeast handling equipment to achieve and maintain high product quality

• Focus on quality is focus on yeast

• Consistent production requires focus on yeast

Yeast Management

scandi brew yeast propagation & storage by mike cholerton sales & technology manager...

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