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IBD 2012 Convention Paper

The use of advanced separation techniques to improve brewers’ profitability and quality control

management

Ir. Minh-Tâm Nguyên* 1, Dr. Ralph Heusslein2, Ron Johnson3, Jürgen Ziehl4

1 Market Manager Beer Asia, Life Sciences - Pall Filtration Pte Ltd, Singapore 2 Vice President, Food and Beverage Technical and Process Services - Pall GmbH, Germany 3 General Sales Manager Beer Americas, Life Sciences - Pall Corporation, USA 4 Global Development Manager Beer, Life Sciences - Pall GmbH, Germany

© Copyright 2012, Pall Corporation. Pall, , Keraflux, Membralox, Ultipor and Palltronic are trademarks of Pall Corporation. ® Indicates a trademark registered in the USA. Filtration. Separation. Solution.SM is a service mark of Pall Corporation.

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Table of contents Abstract ...................................................................................................................... 3 Introduction................................................................................................................. 4 Recovery of Beer from Surplus Yeast ........................................................................ 5

Principle .................................................................................................................. 6 Description .............................................................................................................. 7 Procedure ............................................................................................................... 7 Discussion..............................................................................................................10

Beer Final Filtration ...................................................................................................11 Sterility in Beverage Industry .................................................................................11 Principles ...............................................................................................................12 Description .............................................................................................................14 Procedure ..............................................................................................................16 Discussion..............................................................................................................17

Summary ...................................................................................................................18 References ................................................................................................................19

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Abstract In an increasingly challenging brewing market it became critical to significantly reduce energy cost, water consumption, raw materials usage and waste stream in beer production while preserving beer quality. The implementation of advanced separations techniques can improve a brewer’s profitability in a sustainable manner. Recent IBD’s papers interestingly featured kieselguhr-free technology as the “New Way to Filter Beer in the Southern Hemisphere” by Meehan15 and, “Membrane systems for recovery of waste water to reduce brewery water footprint” by Brister4. The focus of this lecture is to report on the use of the latest separation techniques applied to the brewing process such as: � crossflow filtration for recovering high quality beer from surplus yeast, � direct flow filtration applied to “sterile” membrane filtration for ensuring the

microbiological stability of beer.

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Introduction All food and beverage industries use filtration in their processes. The brewing industry is no exception. From a filtration perspective, the brewing process can be viewed as a succession of filtration steps using various separation technologies to remove contamination from a fluid (liquid or gas) in order to achieve a required level of fluid cleanliness (refer to Figure 1).

Figure 1 – The brewing process - a succession of various filtration steps

One can classify the filtration process into two categories: direct flow filtration and crossflow filtration in which contaminants are collected on surface or in the membrane’s structure, and contaminants are circulated and concentrated within the crossflow loop, respectively. In an increasingly challenging brewing market it has become critical to significantly reduce energy cost, water consumption, raw materials usage and waste stream while preserving beer quality. The implementation of advanced separations techniques can improve a brewer’s profitability and protect their brands sustainably. Recent IBD’s papers interestingly featured kieselguhr-free technology as the “New Way to Filter Beer in the Southern Hemisphere” by Meehan15 and, “Membrane Systems for Recovery of Waste Water to Reduce Brewery Water Footprint” by Brister4. The focus of this Paper is to report on the use of the latest separation techniques applied to the brewing process such as: � crossflow filtration for recovering high quality beer from surplus yeast, � direct flow filtration applied to “sterile” membrane filtration for ensuring the

microbiological stability of beer.

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Recovery of Beer from Surplus Yeast A few decades ago beer recovery systems were popular in breweries for reducing beer losses in relation to beer excise duties in effect at the time. The organoleptic quality and colloidal stability of the recovered beer was often low due to higher oxygen level, longer residence times and higher pasteurization temperatures used for preventing microbiological contamination. These factors, together with new beer excise duties in force eventually meant these practices were discontinued (refer to Figure 2).

Surplus yeast

Traditional beer

recovery system

Low quality beer

Fed back to fermenting vessels,

brewhouse or waste water

treatment plant

Sewage or sold for animal food

production

Pressed yeast

Surplus yeast

Traditional beer

recovery system

Low quality beer

Fed back to fermenting vessels,

brewhouse or waste water

treatment plant

Sewage or sold for animal food

production

Pressed yeast

Figure 2 – Valuation of surplus yeast process with traditional technologies

There are various techniques available for recovering the beer component from the surplus yeast as presented by Buttrick5. Each provides different results in terms of beer quality, ease of handling, yeast dry matter and financial payback. Typical conventional technologies are: � Filter press: Yeast slurry is fed into a filter chamber press and the beer is filtered

through polypropylene cloths. Low investment is required. Pressure (4-18 bars) is applied to press the yeast cake but due to low quality of the recovered beer the latter is seldom returned to the brewing process. The pressed yeast (approx. 25% dry matter) is usually sold to animal food processors.

� Decanter centrifuge: High variable speed horizontal centrifuge designed to handle

a broad range of spent yeast dry matter content produces yeast up to 26-28% dry matter. The screw may damage the cells integrity hence reducing the quality of the beer recovered. Also the latter features a higher yeast count which is usually addressed via a smaller centrifuge and flash pasteurizer downstream from the main system. High investment is required for decanter centrifuge including above mentioned additional equipment.

� Continuous discharging disk bowl nozzles centrifuge1: compact and hygienic for

concentrating yeast slurries up to 20-25% dry matter. The nozzle separator design requires relatively stable consistency of the flow intended for separation hence an upstream dilution unit for reaching approx. 30-45% by volume and eventually a higher recovery yield. The recovered beer quality: yeast < 50,000 cells/ml, O2 pick-up < 50 ppb and dosing up to 5%.

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Nowadays with larger brewery sizes, increasing cost of raw materials, energy and waste disposal, brewers are forced to consider all opportunities for increasing the overall brewery yield while preserving the beer quality in a sustainable manner. As an example, a brewery with an annual production capacity of 3 million hectoliters of beer at 16° Platoa would generate about 90,000 hl per annum of surplus yeastb (refer to Figure 3).

Surplus yeast

CROSS FLOW

beer recovery

system

HIGH QUALITY

HIGH VALUE beer

Fed back UPSTREAM

PRIMARY FILTRATION

Sold for

� animal food production

� HUMAN food production

� PHARMACEUTICAL industry

� COSMETIC industry

QUALITY spent yeast

Surplus yeast

CROSS FLOW

beer recovery

system

HIGH QUALITY

HIGH VALUE beer

Fed back UPSTREAM

PRIMARY FILTRATION

Sold for

� animal food production

� HUMAN food production

� PHARMACEUTICAL industry

� COSMETIC industry

QUALITY spent yeast

Figure 3 – Valuation of surplus yeast process with crossflow technology

Obviously for meeting the standards required for high value recovered beer while providing brewers with a sustainable economical solution, latest separation techniques and only fully automatic closed systems should be considered such as a cross flow filtration system as shown by Gottkehaskamp10.

Principle In crossflow (or tangential flow) filtration, the unfiltered solution (yeast slurry) flows through the feed channel and tangentially to the surface of the membrane as well as through the membrane (refer to Figure 4).

Figure 4 - Schematic crossflow filtration process

a 4 mio hl at 12° Plato. Detailed calculations achieved for each project based on brewery specificities b Surplus yeast amount estimated to 3% of brewery annual production at 16° Plato

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The crossflow prevents build up of molecules at the membrane surface that can cause fouling hence enabling slower decline in flux rate and greater volume to be processed per unit area of membrane surface as compared to direct flow filtration process.

Description The Keraflux® TFF system for beer recovery from surplus yeast is a fully automated closed system. Its modular design can accommodate both: � brewery capacity ranging from 0.5 up to 10 million hectoliters per annumc and

capacity increase with additional membrane filtration surface; � brewery specific footprint with extension either along vertical or horizontal axis.

The Membralox® multi-channel ceramic membranes (refer to Figure 5) – produced by Pall Corporation - are the heart of the system. They are made of ceramic material - layers of pure �-alumina oxides – which offer excellent resistance to corrosion, excellent thermal stability and can be sanitized and sterilized. Each module has 13 m2 of effective filtration surface and a defined membrane cut-off which enables almost complete removal of suspended solids providing a virtually particle free effluent stream reducing waste treatment costs while preserving the quality of the beer recovered.

a/ Cross section of Membralox b/ Membralox ceramic c/ Membralox ceramic module ceramic membrane (x1010) membrane

Figure 5 – Membralox membrane

Procedure The yeast slurry is fed into the Keraflux TFF system under regulated feed flow and temperature using a fed-batch mode process (refer to Figure 6) which enables lower yeast concentration in system hence reducing energy consumption and increasing recovery yield up to 80% using diafiltrationd (refer to Figure 7). Moreover, for increasing energy efficiency, prolonging production cycles and reducing cleaning cycles the pumps, for crossflow velocity and filter feed flow are frequency controlled and the permeate flow and trans membrane pressure (TMP) at each module level are regulated against target set points.

c 12°Plato and yeast amount 3% (beer volume at 12°Pl), 250 working days/year and 21 hours/ day d Water addition to yeast slurry to eventually increase extract and alcohol recovery without compromising beer quality.

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Figure 6 – Crossflow filtration system equipped with 2 x 3 Membralox

membrane for beer recovery from surplus yeast Separation starts without addition of water. Usually filtration stops when the dry matter reaches a value between 17% and 20%, which is yeast specific. The flux is mostly constant due to the high degree of automation and control mechanisms. Diafiltration process (option) can further improve extract and alcohol recovery. This specific process will commence at 14% dry matter controlled by °Plato measurement and stops at 8 °Plato to preserve quality of beer.

Extract / °Plato Dry matter / %

8

15

12

20

˜

14water

dosing

Yield > 80%

Extract / °Plato Dry matter / %

8

15

12

20

˜

14water

dosing

Yield > 80%

Figure 7 – Diafiltration process enables yield recovery up to 80%

During the complete filtration process neither intermediate cleaning nor back-flushing is necessary. Each filtration cycle lasts about 21 hours after which a 2 hours cleaning processe takes place (80°C NaOH at 2- 3%).

e Additional cleaning with 1 % HNO3 and 0.5 % membrane cleaner weekly

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Extract recovery rates may reach up to 80% based on initial yeast volume without compromising beer quality. All analytics were carried out by a German Research Institute for Brewing. A taste panel was carried out according to DLG 5 point taste testing protocol. The results show a maximum difference in the level of 0.1 points out of 5 points between original beer and blended beer (1% and 5% blending rate). All results are in the upper level of premium beers. Basic analytics show a minimum deviation (within analytical failure rate) between the original beer (0% line) and the blended beers (refer to Figure 8). 100% recovered beer shows higher values in color and bitter units (mainly caused by oxygen uptake during sampling at system).

-2% 3% 8% 13% 18%

Colour

pH

Bitter UnitsFoam (Nibem)

5% blending rate1% blending rate100 % recovered beer

Figure 8 – Minimum deviation on beer quality up to 5% blending rate

Results on ester show no significant differences between original beer and 100% recovered beer, 1% and 5% blended beer.

0,590,680,490,69Caprinic acid

2,402,503,942,50Caprylic acid

0,270,270,360,25Iso Valerianic acid

0,750,761,150,75Capronic acid

5% Blend1% Blend100% Rec.Original Substance (ppm)

0,590,680,490,69Caprinic acid

2,402,503,942,50Caprylic acid

0,270,270,360,25Iso Valerianic acid

0,750,761,150,75Capronic acid

5% Blend1% Blend100% Rec.Original Substance (ppm)

4,96,35,36,92-Furfural

3,52,86,53,23-Methylbutanal

16,515,726,118,7Phenylethanal

n.nn.n3,5n.nMethional

1,91,42,51,42-Methylbutanal

0,71,11,31,0Benzaldehyde

6,97,912,58,2Nicotin Acid Ethylester

5% Blend1% Blend100% Rec.Original Substance (ppb)

4,96,35,36,92-Furfural

3,52,86,53,23-Methylbutanal

16,515,726,118,7Phenylethanal

n.nn.n3,5n.nMethional

1,91,42,51,42-Methylbutanal

0,71,11,31,0Benzaldehyde

6,97,912,58,2Nicotin Acid Ethylester

5% Blend1% Blend100% Rec.Original Substance (ppb)

Analytics according to MEBAK III 1.1.4 // SAFE* in combination with GC/MS (VLB method)

* Solvent Assisted Flavor Evaporation

Figure 9 – No significant difference in ester concentration and stale favor active substances up to 5% blending rate

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Some short chain fatty acids show a slight increase in the 100% recovered beer against original and blended beers (see listed substances). All data are below taste threshold and in normal range of typical lager beer (refer to Figure 9). Stale flavor active substances show an increase in Strecker aldehydes (oxygen indicator) in the 100% recovered beer only, resulting from high oxygen uptake during sampling. Other indicators such as Nicotin Acid Ethylester and 2- Furfural (thermo indicator) show minimal to no change respectively. Between original beer and blended beer (1% and 5%) there was no difference at any time. All data are below taste threshold and in normal range of typical lager beer. By chemical and sensory analysis carried out by independent institutes, it was shown that a back blending ratio up to 5% volume is suitable.

Discussion The Keraflux TFF system developed by Pall meets the brewer’s needs: � Profitability improvement by recovering beer from excess yeast; � Sustainable concept by reducing the waste stream and valuing waste; � Brand protection by guaranteeing quality of blended beer. Case study: a brewery with an annual production capacity of 3 million hectoliters of beer at 16° Plato would generate about 90,000 hl per annum of surplus yeast. By recovering beer from this surplus yeast brewers may: � boost their profitability by $1.1 million USD per annum with a short ROI within 1 -

1.5 yearsf; � increase their annual production capacity by 110,000 hlg � reduce their current spent yeast stream up to 32,000 hl per annumh � resell spent yeast up to $500 USD / ton at 90% dry matter for some specific

applications while ensuring the quality of their final beer at all times.

f Beer production cost estimated at $10 per hl; Return On Investment (ROI); CAPEX $1.5 million USD for system and periphery (estimate); OPEX $0.6 USD per hectoliter recovered g Yield recovery up to 80% with dia-filtration process to 10.5° Plato h Estimate

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Beer Final Filtration Pasteurization aims to kill bacteria, if present in beer, and to destroy yeast viability hence preventing further growth in beer. Also, brewers want to maintain the optimal time and temperature profile for protecting their beers against under or over pasteurization while producing microbiologically stable beers. Flash and tunnel pasteurization - heat treatments occurring pre or post filling respectively - present similar investments especially when considering requirements for aseptic filling lines and clean rooms intrinsically linked to flash pasteurization. However, the latter requires less floor space, steam, electricity and coolant compared to conventional tunnel pasteurization. Eventually any heat treatment will have a negative impact on the taste of beer. An attractive, sustainable and economical alternative to pasteurization is beer “sterile” filtration or beer final filtration prior to filling. The latter is based on “direct flow filtration” which is the second type of filtration to be discussed in this paper after the crossflow filtration described earlier. With beer final filtration, brewers benefit from a fresh and natural beer taste as the absence of heat treatment and related filtration process will not negatively affect the quality or stability of the beer. Moreover, lower investment costs, smaller footprint, reduced energy consumption, minimized beer losses and no damaged glass bottles are advantages as compared to traditional tunnel pasteurization. Eventually the in situ integrity testing of the filter ensures the microbiological protection of the brand.

Sterility in Beverage Industry As explained by Dr. Heusslein13 the concept of sterility in the food and beverage industry is less defined as compared to pharmaceutical applications. In pharmaceutical applications a sterilizing grade filter has very clear performance definitions and requirements for performance validation as published in 1982 by the Health Industry Manufacturer’s Association, updated and repositioned by the FDA (Guideline on aseptic processing) or within the EU (Guideline of Good Manufacturing Practice for Pharmaceutical Products), the up-to-date position on membrane filtration is outlined by the PDA Technical Reports. Brewers used the term ‘sterility’ in a pragmatic way and imply a microbiologically stable product and not one free of all microbes. The Codex Alimentarius Commission (WHO/FAO) CAC/RCP 40-19936 defines the term commercial sterility for low-acid food: Commercial sterility means the absence of microorganisms capable of growing in the food at normal non-refrigerated conditions at which the food is likely to be held during manufacture, distribution and storage. The term ‘sterility’ in food and beverage applications refers to a product which is microbiologically stable under foreseeable conditions over the entire shelf life and is achieved by the combination of process steps including all aspects of hygienic processing to control the microbiological status and to avoid secondary contamination. These aspects are often summarized under good manufacturing practices used to produce a stable product.

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Whether heat treatment or filtration is utilized, the likelihood of a microorganism being in the final product is not zero. Major factors of influence when using heat include the time and temperature of heat exposure (linked with volume throughput), the initial number and type of microorganisms and their heat-resistance. With filtration the likelihood of a microorganism ending up in a unit of final product is a matter of the volume of this final product, the level of contamination upstream and the efficiency of the membrane to retain organisms in the process stream. The total volume processed, equivalent to the number of units produced, has direct influence on the total number of contamination events. All these considerations indicate that it might be more appropriate to reflect on the residual risk for a final product to be contaminated or even spoiled and to define a residual maximum level of microbiological contamination leading to a stable product. Ideally, major aspects should be validated in risk analysis. A continuous system and maintenance control are other important aspects in order to ensure higher security and lower risk for the process. A regular integrity test by automated test apparatus as proposed with Pall systems, adequate documentation and trend analysis of the integrity test values, as well as records of process parameters like temperatures and pressure during sterilization of filters during filtration, should ideally be part of such a surveillance system3.

Principles Microorganisms like bacteria and yeast in beer should usually be avoided in the end product. Both types of microbes are retained mechanically by filtration, but not to a level of 100%. Because of their larger size, it is easier to remove yeast and by appropriate fine filtration yeast cells might be fully removed. Control of bacteria is more challenging due to their cell size, motility and replication time. After primary filtration and before final filtration the maximum acceptable levels of bacteria in beer are typically less than 10,000 CFU/ml. In the case of beer there is an emphasis on enumeration of specific beer spoiling organisms like Lactobacillus lindneri or Pediococcus damnosus. Depending on the source of information the resulting acceptable level of bacteria in a volume of 1 liter of beer is about 1 CFU. Filter removal ratings, if expressed as LRV (Logarithmic Reduction Value or Titre Reduction), describe the likelihood of a particle or cell to pass through the membrane.

Total number of microorganisms influent to the filter LRV = log

Number of colonies recorded on the downstream analysis disc

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The risk or likelihood of having contamination in a batch of beer bottles is given by: � titre reduction including all factors affecting filter performance; � upstream contamination per total volume; � final product volume. These parameters can be a put into a simple formula, where the likelihood (LUnit) is the probability to find a microbiologically unstable product. It is calculated by multiplying the unit volume (ml) with the upstream contamination level (CFU/ml) divided by the titre reduction provided by the filter:

Unit vol [ml] x upstream contamination level [CFU/ml] LUnit =

Titre Reduction The risk for the individual product to be spoiled – provided this is about spoilage organisms – is directly linked to the product volume and the upstream contamination level. The likelihood to have contaminated product in a batch LBatch is simply a result of the number of units produced with this LUnit.

LBatch = Total number of units × LUnit In a simple example, a filter with a titre reduction of 1,000,000/1 or LRV 6 is used to fill into 100 half litre bottles. At a contamination of 20 CFU/ml coming from the process this will lead to a likelihood of a specific unit to be spoiled (LUnit) of 0.01 or 1% (= 1 bottle out of 100). The likelihood (LBatch) that at least one product in that batch is contaminated is 1 or 100%. In order to define the right filter in terms of microbiological performance in a theoretical example, we assume it is intended to reduce from an upstream level of 10,000 CFU/ml (104/ml = 107/L) for a certain type of microorganism in beer to 1 CFU/L (100/L). Would a filter providing a reduction by a factor of 10,000,000 (equals LRV 7) be sufficient? Provided the filter has a specified LRV of at least 7 (ideally measured with this microorganism in beer), putting it into the process would result in an average contamination of 1 CFU per litre of beer. To express it differently, if this beer is filled in 0.5 litre bottles 50% of the batch will be likely to be contaminated. With another filter providing a LRV of 9 in the same situation the percentage of contaminated product will drop to 0.5%, with a LRV of 11 it would be 0.005%. Apart from this mathematical exercise, what level is acceptable or seen as a risk is dependent on the individual risk assessment (reflecting on product, storage conditions, shelf life and other factors) as shown by Dr. Heusslein13.

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Description Polymeric membranes in cartridge style form - greater flow rates and volume throughput in a compact design compared to flat or lenticular membranes - have become one of the most commonly used materials for final filtration of beer as described by Johnson14. These membranes are characterized by a very stable and consistent pore structure, excellent cleaning and sterilization characteristics, and most importantly their verifiable ability to remove beer spoiling microorganisms. Pall Corporation recommends two types of filters for final beer filtration:

a/ Membrane cartridges b/ Ultipor N66 nylon membrane

Figure 10 – Beer final filtration cartridges � Pall Ultipor® N66 filter cartridge 0.45�m with a nylon membrane featuring high

LRV (refer to Figure 10); � Pall® BB Final Beer cartridges 0.45�m with a polyethersulfone membrane

specifically designed for minimized color reduction in very light beers Cartridges offer the possibility to test their integrity prior to use, providing brewers with product/brand protection and peace of mind. The FDA (Sep. 2004) recommends the following procedure: “Integrity testing of filter can be performed prior to processing, and should be routinely performed post-use. It is important that integrity testing be conducted after filtration to detect any filter leaks or perforations that might have occurred during filtration. Forward Flow and bubble point tests, when appropriately employed, are two integrity tests that can be used » Several tests have been developed for testing the integrity of final filters but vary according to manufacturers and types of membrane used. The ideal integrity test should be non destructive, quantitative, sensitive, accurate, reproducible, operator independent and last but not least correlated to the retention of a specific microorganism, preferably a beer spoiler. The following tests are commonly used for this purpose: the Pressure hold test and the Forward Flow Test (FFT), the latter uses the Palltronic® Flowstar device. In a FFT a set amount of pressure is applied to the upstream side of a wetted filter

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membrane17 and the gas flow across the wetted membrane is measured either directly or indirectly using instrumentation. 'The two above mentioned cartridges have been qualified based on their microbial filter performances, physical properties under defined laboratory conditions12,2,7 as well as materials of construction for beer final filtration. Food contact materials need to comply with relevant users legislation. If for example the European Framework Regulation on Food Contact Materials - European Regulation Number (EC) number 1935/2004 applies to these plastic filters in food contact applications, and the company placing these items on the market as food contact products has to provide a 'Declaration of Compliance' demonstrating applicable compliance of materials and tests for extractable substances under relevant conditions simulating the actual use in this case with an alcoholic simulant representing beer.' Regarding the bacterial challenge of final filter applications there is neither a standard test nor a standard test organism established but Serratia marcescensi is typically used as the reference microorganism for validating 0.45 �m filters. Bacterial challenge tests under standardized conditions allow the validation of the specific diffusional forward flow value through an integer membrane For better characterization of beer final filtration performance some typical beer spoiling organisms such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus – have been selected for additional challenge works in beer, being as close as possible to the application (refer to Figure 11). These microorganisms need great care and effort to control cell size, chain length and cluster-forming behavior which depend on the medium and the culture growth conditions. Further tests were performed to demonstrate the ability of these 0.45 �m beer final filters to fully retain yeast (Saccharomyces cerevisae).

Bacteria approximate dimensions (microns) Serratia marcescens 0.5-0.8 x 1.0-5.0 rods Pediococcus damnosus > 0.6 short rods, clumping Lactobacillus brevis 0.5 x 2 rods, clumping Lactobacillus lindneri 0.5 x 2 rods, mostly single cells Yeast Saccharomyces sp ~3

Figure 11 - Serratia marcescens and common beer spoiling bacteria The microbial performance17,18 of these final beer filters is calculated using a statistical assessment of microbiological data (refer to Figure 12). Challenge level was intentionally relatively low to avoid clumping and therefore limiting the LRV.

i This microorganism has been extensively studied for bacterial challenge testing in other application areas.

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Figure 12 – Titre Reduction or LRV with typical beer spoiling microorganisms for Pall Ultipor N66 (for at least 95% of the tested samples) and Pall BB Final Beer filters (for at least 80% of the tested samples). Filters subjected to microbial challenge tests were randomly sampled from standard production and from 3 different manufacturing lots.

Procedure For small size breweries, (< 80Hl/h) housings are designed for cartridges with AB style, double o-ring, bayonet lock with an inverted configuration for reducing oxygen pick-up during the start-up phase and improved back flushing or cleaning of the cartridges hence reducing operation costs. For medium / large size breweries (from 80 up to 500 Hl/h) a fully automated Cluster Filtration System (CFS) is proposed (refer to Figure 13). With the exception of manual mounting and dismounting of the cartridges, all processing steps are performed via a PLC. Simple operation and supervision, process visualization and individual programming requirements are standard.

a/ Pall CFSj for beer final filtration b/ Clusters - individual groups of fully with pre-filter up to 500 Hl/h isolatable filters

Figure 13 – Fully automated beer final filtration system As explained by Weber and Ziehl20 the Cluster Filtration System features: � 5 up to 18 clusters based on the capacity required. Each cluster - composed of 7

cartridges – can be separately integrity tested and isolated if required hence providing brewers with high system availability. In the event of a cluster integrity test failure, the related cluster is simply by-passed and filtration can readily resume, while in conventional systems the identification and replacement of the faulty cartridge(s) may stop the production for a couple of hours.

j CFS – Cluster Filtration System

Ultipor N66 Pall BB Final Beer Saccharomyces cerevisae Sterile filtrate Sterile filtrate Lactobacillus brevis 8.2 7.2 Lactobacillus lindneri 9 n.a. Pediococcus damnosus 8.2 6.6

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� Cleaning with hot water or sporadically with alkali or enzyme solutions. Each cluster is sequentially and individually rinsed improving the cleaning efficiency and minimizing water consumption.

� The patented enzymatic cleaning process ensures a longer life of the cartridges

hence reducing operating costs. � The CFS systems can be equipped with or without pre-filter depending on the

pre-treatment of beer for protecting the final step hence lowering cost. Optimum performance of a final filter system, in terms of both microbiological removal and economy, depends on the entire production process, and particularly to pre-filtration and cleaning regimes. Pre-filtration of beer should be designed to remove yeast and other particulates commonly found in freshly matured beer. Final filter assemblies generally cost more to operate, so they should be employed for the designed bacterial removal work. A system consisting of three stages (particle or trap, pre-filter and final) post diatomaceous earth filtration provides the highest operational efficiency and best economy.

Discussion Heat treatments will kill bacteria and prevent post fermentation in beer but may negatively impact the taste of beer. Hence the advantage of beer final filtration with membrane which preserves the freshness and natural beer taste without affecting the quality or stability of the beer. As indicated by Galitsky9 the initial investment for a flash pasteurizer or final filter system represents about 15% of the investment required for conventional tunnel pasteurization but one should keep in mind that the first two systems are also intrinsically linked to aseptic filling line and clean room investments and would require less floor space, steam, electricity and coolant compared to conventional tunnel pasteurization. In a challenging brewing market environment it has become critical to significantly reduce both energy and water consumption while preserving beer quality and protecting the brand. The energy consumption8,11,19 for a flash pasteurizer is estimated around 750-1,800 kWh/Hl which represents roughly a third of the energy required for a tunnel pasteurizer. Final filter system would require only about 10% of the flash pasteurizer energy requirement. Operation and maintenance costs as shown by Dymond8 were estimated about $0.2-0.25 USD/Hl for flash pasteurization and $0.25 USD/Hl for a final filter system compared to $1.4 USD/Hl for conventional tunnel pasteurizer. In conclusion, beer final filtration has become an attractive, sustainable and economical alternative to pasteurization systems.

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Summary The implementation of advanced separations techniques can improve brewers’ profitability in a sustainable way while preserving the quality of their beers: � Crossflow filtration applied to beer recovery from surplus yeast features an ROI

within 1 - 1.5 years generating revenues about $1.1 million USD per annum with production capacity increase around 110,000 hl and waste stream reduction by 32,000hl p.a. while ensuring at all time the beer quality.

� Direct flow filtration applied to beer final filtration preserves the freshness and

natural beer taste without affecting the quality or stability of the beer. With operational costs at $0.25 USD/Hl vs. $1.4 USD/Hl for conventional tunnel pasteurizers, beer final filtration has become an attractive, sustainable and economical alternative to pasteurization systems.

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Retention of Membrane Filters Utilised for Liquid Filtration’, ASTM Standard F838-83, ASTM, Philadelphia, PA, 1983, Revised 2005

[3] Brendel-Thimmel U. et al., Chemie Ingenieur Technik ‘Sterilfiltration von Flüssigkeiten und Gasen’,

November 2006, 1655, CITEAH 78/11 1579-1750 ISSN 0009-286 X, 2006 [4] Brister R. and Morrow N., The Use of Membrane Systems for Recovery of Waste Water to Reduce

Brewery Water Footprint. Convention Paper. 31st Convention Gold Coast – Queensland. The Institute of Brewing and Distilling - Asia Pacific Section, 2010

[5] Buttrick P., Recovery of beer from tanks bottoms – The Brewer & Distiller, volume 2, Issue 4 April 2006, 19

-22 [6] Codex Alimentarius Commission (WHO/FAO) CAC/RCP 40, Code of Hygienic Practice for aseptically

processed and packaged low-acid food, 1993, p. 3 [7] DIN 58355 Teil 1-6 Membranfilter und DIN 58356 Teil1-12 Membranfilterelemente, Beuth Verlag, Berlin [8] Dymond G., Pasteurization of Beer in Plate Heat Exchangers: Lower Costs and Higher Quality. Cerevisia

22(4), 1997, p. 37-48 [9] Galitsky C., Martin N., Worrel E. and Lehamn B., Energy Efficiency Improvement and Cost Saving

Opportunities for Breweries. Report issued by the University of California Berkeley and sponsored by the US Environmental Protection Agency, 2003

[10] Gottkehaskamp L. and Schlenker R., Processing excess yeast in Keraflux plants. Brauwelt International

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