Date- February 2016 Location -TOOHEYS Brewery NSW Australia

Vibronic Level Detection Device for
gravity measurement in a Yeast
Propagation Vessel
Author - Haydon Morgan (Technical Brewer)
Date - February 2016
Location -TOOHEYS Brewery N.S.W Australia
Abstract
Trial the suitability of a vibronic level device (Liquiphant M) in position of a propagation vessel to determine if aeration from sparging or CO2 produced from yeast will give consistent
specific gravity results and not impact reliability of measurement in tank, hence evaluating effectiveness of this technology in a yeast propagation vessel. This inline measurement would
eliminate manual offline check and ensure optimal transfer of yeast prop system when in exponential phase (log phase). Currently this technology is not used in a yeast propagation vessel.
This poster will review trial results vs offline measurement then present the outcome of this trial.
Background
Trial Process Continued
The Tooheys yeast propagation plant is a 3 vessel system to propagate yeast from a
Carlsberg flask to commercial brewing stage for 6 different yeast strains comprising of both
Ale and lager. There was a need to be able to track plato drop during propagation in tank to
support plant operations.
Trial commenced on 29th December 2014 until 5th May 2015. During this period there were
22 offline samples compared to inline. 81% were within 1 plato difference of offline. Below
is a comparison of samples from YP02. The inline tank plato is generally slightly higher than
offline measurement. This could be due to time difference between offline sample and
online measurement and optimising liquipant M reading vs handheld Anton Paar.
Before a suitable measurement device was selected for in-tank trialling, there were
numerous criteria the technology had to meet, this is outlined below:
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The Yeast Propagation Plant (YPP) did not have any inline measurement for specific gravity
(Plato) to indicate optimum time (Logarithmic phase) to transfer yeast to the next vessel.
The trial consisted of installing an E&H Liquiphant M Density device in Yeast Propagation tank
2 to evaluate and trial inline plato measurement vs offline measurement (handheld Anton
Paar - DMA 35). The aim was to ensure plato measurement was consistent and no greater
than 1 plato difference from offline. Approximately a third of transfers between propagation
vessels are completed remotely by duty brewers. Hence the importance of accuracy from
inline instruments to indicate and validate yeast is in Logarithmic phase before transferring
to next stage in propagation.
Tooheys had installed Liquiphants on yeast lines previously to determine specific gravity/
yeast concentration with mixed results. Previously liquiphants had been used as a low level
switch (LSL) or a high level switch (LSH) in a vessel but not for gravity
measurement. This technology had not been applied to a vessel.
Trial Process
A trial was initiated with the Liquiphant M density and density computer in the yeast
propagation plant at Tooheys to determine devices effectiveness for gravity measurement.
Yeast propagation Tank 2 (YP02) was selected as it had a tri-clover hygienic fitting with
manual temperature gauge at mid level of tank .This was removed and replaced with a
Liquiphant M density device and integrated into Tooheys Ifix batch control system. There
were unknown's from supplier for application in the Yeast propagation vessel environment.
YP02
As seen below SCADA trends show a consistent trend through the propagation process in
YP02
Plato
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Polished device
Ability to withstand propagation processes, sterilised with steam at 98 degrees and hot
caustic CIP at 85 degrees)
Low maintenance
Integration into current control system (IFix batch, Siemens S7)
Cost effective
Plato reading within +/- 1. This was required due to conditions of YPP with aeration
sparging and CO2 environment
Plato

Comparison of in-tank Plato vs Ofline
Time
Time
Conclusion/Next Steps
The result of this trial has been a successful application of this technology for specific gravity
measurement in a propagation tank. Some yeast strains have impacted the accuracy of the
liquiphant in tank due to excessive CO2 production during propagation.
The next opportunity are to initiate recipes to transfer on time and plato automatically
when yeast is in the logarithimic phase. This will remove manual intervention in the
propagation process and ensure exceptional viable yeast.
The next steps are to install 4 more Liquiphant M the remaining Yeast propagation vessels
YP01, YP03, YP11 and YP12 to allow further optimisation.
Acknowledgements
24hL
The Author would like to acknowledge the contribution of
team members of the YPP project at Tooheys and technical support:
Liquiphant M with a tri-clover
fitting in YP02
Melissa Aistrope, Insa Errey, Jaspal Jassal, Savio Fernandes, Lucia
Echevaria, Derek Liebenberg, Brett Sinclair and Noah Minor.