Membrane Separation Processes for the Beer Industry: a Review and State of the Art

REVIEW

Membrane Separation Processes for the Beer Industry: a Reviewand State of the Art

Alan Ambrosi & Nilo Sérgio Medeiros Cardozo &

Isabel Cristina Tessaro

Received: 3 October 2013 /Accepted: 29 January 2014 /Published online: 15 February 2014# Springer Science+Business Media New York 2014

Abstract Beer is one of the most consumed beverages in theworld, placing the brewing sector in a strategic economicposition in the food industry. Beer production has a series ofphysical and chemical steps that are technically intensivewhen the production scale is increased. Although the produc-tion techniques have been improving for hundreds of years,many breweries still employ traditional techniques. The in-creasing consumption of beer and the competitive mar-ket have led the industry to search for alternative tech-nologies to produce a better beer with reduced prices.Membrane separation processes are interesting alterna-tives that may be utilised in several steps of beerproduction and may replace some traditional and time-consuming techniques. The objective of this study is tosummarise and present a literature survey of the mem-brane separation processes that are currently applied inthe beer industry and those processes that have potentialfor future applications. The potential of microfiltration,ultrafiltration, reverse osmosis, pervaporation, and gas sepa-ration to accomplish almost all solid–liquid–gas separations ina brewery is discussed, providing a clear outline for re-searchers on the main aspects and developments of the beer-membrane field.

Keywords Beer . Brewing industry .Membrane technology .

Membrane separation processes

Introduction

The fundamentals of beer production have nearly remainedthe same since the invention of the beverage, with mashing ofa cereal, separation of the wort, and fermentation composingthe main processes used around the world. Additionally, thestandard beer composition is based on the German Purity Law(or Reinheitsgebot, from Germany), which states that beer canonly be made from malted barley, hops, yeast, and water.Despite this tradition, the techniques of production, quantityproduced, and ingredients used vary from region to region,and hundreds of types of beer are normally classified accord-ing to the Beer Judge Certification Program (BJCP).

The production of beer holds a strategic economic positionin the food industry. Beer production totalled 185 billionhectolitres per year in 2010, with almost 92 % of beer brewedin the 40 main beer-producing countries. China is the topworld producer, with more than 449 million hectolitres,followed by the USA, Brazil, Russia, and Germany (BMG2011). The large consumption of beer has motivated researchgroups and industry to study and develop new technologies toproduce low-cost and high-quality beers.

Membrane technology has been studied and used in thebrewing industry for many years in a variety of solid–liquidseparation processes, either replacing or being combined withmore traditional methods (Daufin et al. 2001). In general,membrane separation techniques offer significant advantagesover traditional technologies, including capable separation ofmolecules and microorganisms, lower thermal impact onproducts, moderate energy consumption, and modular design.These filtration techniques may be used in different stages ofbeer production, including raw water treatment, brewing pro-cesses, and wastewater/effluents treatment. Microfiltration(MF) is the most widely used membrane separation processin the beer industry because the majority of the operationsrelated directly to the beer involve solid–liquid separation.

A. Ambrosi (*) :N. S. M. Cardozo : I. C. TessaroLaboratory of Membrane Separation Processes, Department ofChemical Engineering, Universidade Federal do Rio Grande do Sul,R. Engenheiro Luis Englert, s/n. ZC 90040-040Porto Alegre, RS, Brazile-mail: [email protected]

Food Bioprocess Technol (2014) 7:921–936DOI 10.1007/s11947-014-1275-0

However, ultrafiltration (UF), reverse osmosis (RO), dialysis(DI), pervaporation (PV), and gas separation (GS) are beinginvestigated and/or already utilised in other operations of thebeer industry.

Therefore, the main purpose of this paper is to provide areview of the significant applications of membrane separationtechnology in the beer industry considering the state of the art,limitations, potential applications, and future trends. Emphasiswill be placed on the operations associated directly with thebeer because the use of membranes in raw water treatment andwastewater/effluent treatment has already been discussed indetail in the literature.

The Essentials of Beer Brewing

Traditional beers are made with malted barley, water, andhops. Despite the use of other cereals and unmalted grains inthe elaboration, malted barley is the main cereal in use be-cause, in addition to possessing husks with the ability to forma filter bed, this cereal has high contents of starch and enzymesthat degrade starch to fermentable sugars for the yeast(Bamforth 2006). The hops contribute to the flavour of thebeer with various groups of substances, adding bitterness andbalancing the sweet flavour of the beer.

The water utilised in a brewery is often considered a utility,but this water should be considered a raw material because itfrequently constitutes more than 90 % of the final beer.Depending on water quality and the location of the brewery,the incoming water is typically treated to adjust its composi-tion, and RO is already one of the preferred techniques topromote this adjustment (Bamforth 2006; Briggs et al. 2004;Eumann and Schildbach 2012).

The beer brewing process has a series of steps with themain objective of converting the starch source into a sugaryliquid called the wort or extract and then converting this sugarinto alcohol by yeast fermentation. These steps include chem-ical and biochemical reactions that occur during mashing,boiling, fermentation, and maturation, alternated with solid–liquid separation stages for the separation of wort, wort clar-ification, and clarification of the final beer. To summarise,Table 1 presents the basics of the processes involved inbrewing and the importance of each operation.

Membrane Separation Processes in the Brewery

Membrane separation processes (MSPs) are promising in thebeer brewing process and may replace or be combined withconventional brewing operations to improve beer quality. Thissection presents a review of the current uses of membraneprocesses in the beer industry and a discussion of some newrelated opportunities. The analysis of the literature available

on the use ofmembrane-based systems (MBSs) in the brewingprocess indicates two main situations in which membrane

Table 1 Essentials of the beer brewing process

Process stage Description

Milling andmashing

Barley malt is milled, generating particles (calledgrist) accessible to the mashing water.

A gradual increase in temperature is applied to themash to activate enzymes for the malt, promotingthe breakdown of complex and insolublecarbohydrates into other smaller, simplermolecules.

The conversion of the starch occurs inapproximately 60 min, and then, the wort isseparated from the grains.

Lautering In the lauter tun, a filtration bed is formed by thehusks of the grains contained in the mash,promoting wort separation from the solids

The grains are further washed with water at the samefinal temperature as the mash (typically 78 °C) tocompletely deplete the sugars.

The solid residue generated from the depleted grainsin this step is called BSG.

Wort boiling In a kettle, the wort boils for a period of 60–90 min.Hops are added to provide bitterness and stabilise the

sweet taste of the wort.Aside from allowing the evaporation of the waterused to wash the malt, concentrating the wort, thisprocess serves to inactivate enzymes and steriliseand coagulate proteins.

Whirlpool The wort enters tangentially and at high velocity in alarge vessel, creating a vortex that leads to theagglomeration of proteins, hops, and other solidsin the central cone at the base of the whirlpool.

The solid residue formed in this step is called “hottrub” and is separated from the wort.

Wort cooling Cooling is the last step before fermentation andoccurs as soon as possible to prevent oxidation ofthe wort while it is hot.

A heat exchanger is used to reduce the worttemperature to the desired fermentationtemperature, which must be consistent with thebeer style.

Fermentation Oxygen is bubbled into the wort to help yeast toreproduce itself at the beginning of fermentation.

Yeast is added, converting sugars into alcohol andCO2 aside from other components in parallelreactions. Fermentation of wort can require 3–15 days to complete.

Part of yeast cells and other by-products settle to thebottom of the tank and are separated from the“green beer” after the end of fermentation.

Maturation andpackaging

The maturation occurs at low temperatures (−1 to5 °C) to allow for insolubilisation and settling ofproteins and polyphenols.

The “rough beer” is separated from the tank bottomdeposit and filtered to remove residual hazeprecursors.

Beer may be filtered or pasteurized to remove allmicrobial contamination and packaged intobottles or kegs.

922 Food Bioprocess Technol (2014) 7:921–936

techniques play a useful role (Daufin et al. 2001): (1) the useof MBSs as a technological alternative, replacing convention-al separation processes, and (2) the use of MBSs as an addi-tional step in the process, aiming mainly at loss reduction.These two topics will be addressed separately in the followingsections.

Membrane-Based Systems as Alternativesto the Conventional Separation Processes Used in the Brewery

Mash Separation

After the mashing process, the wort must be separated fromthe barley husks. Although the use of a mash filter is also awell-established practice for this purpose, most brew housesutilise the lauter tun technology (as described in Table 1), aconventional dead-end filtration technique in which a filtra-tion bed is formed by the husks and non-soluble componentsof the grains (which form the brewer spent grain; BSG)(Bamforth 2006; Galitsky et al. 2003). The wort typicallyrecirculates until clear, and then, the filtration bed is washedwith pure water to obtain a higher yield of sugars from theextraction. Because spent grains have to be removed from thetun after each run, lautering is a batch process, which takes upto 2 h per batch and thus constitutes a yield-limiting factor inthe brewery (Bamforth 2003, 2006).

In this sense, cross-flow filtration using microfiltrationmembranes appears as a “continuous” system option to per-form the mash filtration and prevent cake formation. Figure 1illustrates the main differences between conventional dead-end filtration and cross-flow filtration of the mash.

The applicat ion of cross-f low fil t rat ion usingmicrofiltration membranes to promote the mash separationhas been investigated since 1985 (Daoud 1985), but mostattempts to date have been unsuccessful due to the low

filtration rate, high power consumption, and membrane insta-bility caused by abrasive husks and fouling (Schneider et al.2005). Few studies have been published on this subject; theseworks are listed in Table 2, along with the main processparameters considered. A patent, which was the first relatedto this separation, is also cited to facilitate the discussion.

Daoud (1989) filed the first patent related to mash separa-tion using cross-flow microfiltration (CFMF), suggesting theuse of a tubular membrane with pore sizes of at least 10 μmand a four-step process: (1) 40–60 % reduction of the wortvolume; (2) addition of sparge liquor to the mash to recoverthe remaining soluble extract and for recovery of the filtrate(wort) until the specific gravity reaches a prescribed minimumvalue; (3) diversion of the weak wort produced by the contin-ued addition of sparge liquor to a buffer tank that providesliquor for the following batches; and (4) end of the addition ofsparge liquor.

According to Daufin et al. (2001), microfiltration mayproduce high-quality wort, accelerate the operation, exhibitan economical flux, concentrate the initial amount of solids inthe mash (typically 25–30 %) up to a maximum value, andextract more than 90 % of the spent grains from the wort.However, a two-stage process is recommended due to the highamount of solids present in the mash, which would requireoperation under low fluxes to provide complete separation ofwort using a single stage. Daoud (1992) reported high fluxesand a solid removal rate of up to 95 % using tubular stainless-steel membranes with a pore size of 70–80 μm at the firststage, as presented in Table 2. Bühler et al. (1993) suggestedthe use of a centrifuge decanter to separate particles larger than15 μm, followed by the use of CFMF, to clarify the wort andobtain wort satisfying the quality standards.

Schneider et al. (2005) evaluated beer quality after wortseparation with a dynamic membrane filtration apparatus.Poly(tetrafluoroethylene) (PTFE) membranes with a nominal

Fig. 1 Comparison betweendead-end (a) and cross-flow (b)filtration of the mash in beerproduction

Food Bioprocess Technol (2014) 7:921–936 923

pore size of 0.45 μm were able to produce clear wort in termsof turbidity and solid content. MF was capable of removinglarge molecules, such as proteins and β-glucans, from thewort. These large molecules could lead to gel formation andreduce the filterability of the final beer when using a conven-tional cake filtration system. However, aside from these largemolecules, MF also removed substances responsible for foamenhancement and suffered from fouling caused by the depo-sition of the β-glucans and protein complexes.

The use of CFMF for the mash separation allows thebrewer to use finer grinds of malt and also other cereals inthe grist, increasing the operating range of the brewery.Moreover, finer grinds have better yields in the starchconversion and extraction step, leading to reduced pro-duction costs. However, lower-quality malts in conjunctionwith the conventional mashing procedures lead to increasedβ-glucans in the wort/beer, which would be detrimental tomembrane filtration.

β-glucans are responsible for membrane fouling/cloggingin almost all subsequent filtration steps during beer produc-tion, as shown in the following sections. In this context,removing part of the β-glucans during the mash separationcould provide benefits to the subsequent beer filtration steps.Gan et al. (1997) studied the use of enzymes to degrade part ofthe polysaccharides and determine the nature of the beerfoulants during beer filtration. These authors observed thatthe addition of β-glucanases increased the permeate flux by20 %, indicating that β-glucans affect permeation perfor-mance. However, the partial degradation of these polysaccha-rides may also have an adverse effect in terms of fouling.Low-molecular-weight β-glucans have more mobility andthus a higher probability of forming aggregates (van derSman et al. 2012). In this sense, additional studies should beperformed to understand the effects of adding enzymes to thewort during mashing and separating the wort from the mashby CFMF.

Another possibility for the use of membrane technology inmash separation is as an additional step to separate compo-nents from the spent grains. BSG is the major by-product of

the brewing process. This grain is normally sold as animalfeed, but several other uses for this residue have already beenstudied (Mussatto et al. 2006). Due to the presence of manybeneficial components, separation of the BSG into its individ-ual components for both food and non-food applications isimportant (Gupta et al. 2010; Tang et al. 2009). Tang et al.(2009) investigated protein extraction from BSG utilisingalkaline extraction and concentrating/purifying the proteinsby ultrafiltration and obtained promising results. Membranesof 5 and 30 kDa were evaluated, which retained more than92 % of the protein content from the extract and improved thequality of the final product by removing salts.

Clarification of Rough Beer

After the fermentation and maturation steps, in which cold isused to settle part of the yeast and other particles, rough beerstill possesses substances that tend to form particles and hazeduring further commercialisation (Bamforth 2003; Benítezet al. 2013). The consumer normally associates the clarity ofa product to health, purity, and freshness, and thus, filtration ofbeer is a common procedure.

The clarification of rough beer must comply with the hazespecification of the beer to produce a clear, bright beer ac-cording to the European Brewery Convention (EBC) norms.Filtration through kieselguhr, a diatomaceous earth rock, hasbeen successfully used for many years to meet this specifica-tion. However, clarifiers and other agents used in this filtrationcan be considered as hazardous materials such that further usemay conflict with the handling/disposal regulations in manycountries.

The potential of CFMF as an alternative to the use of thefiltration agents has been studied, and successful industrialapplications are already available, with advantages that in-clude quality, fewer environmental issues, fewer health andsafety concerns, simplicity, flexibility, and lower cost(Fillaudeau et al. 2006; Gan et al. 2001).

In general, because MF is size selective, the colloidalconstituents of beer are naturally classified into three classes,

Table 2 Summary of works related to mash separation through cross-flow filtration

Membrane Process Reference

Module Material Poresize(μm)

TMP(atm)

Temperature(°C)

Cross-flowvelocity (m s−1)

Tubular (i.d. >20 mm) Preferably: stainless steel Suitable:ceramic or filter cloths

10–100 0.35–2.1 70–80 2–8 Daoud (1989)p

Tubular Stainless steel 70–80 n.m. n.m. n.m. Daoud (1992)

Tubular Ceramic 1.3 1.3 n.m. n.m. Bühler et al. (1993)

Vibrating membranefiltration

PTFE 0.45 n.m. n.m. n.m. Schneider et al. (2005);Schneider andWeisser (2004)

TMP transmembrane pressure, p patent, n.m. not mentioned, i.d. internal diameter


as shown in Table 3 (van der Sman et al. 2012). Solublemacromolecules present in beer, such as proteins and carbo-hydrates, are responsible for foam and sensory attributes, sothese biomolecules must remain in the beer. These particlesizes justify the typical selective nominal pore diameter (0.45–0.65 μm) used in practice, with commercial membranes typ-ically made of poly(ethersulphone) (PES) (Sensidoni et al.2011; van der Sman et al. 2012).

The clarification of rough beer using microfiltration hasbeen well studied, especially regarding flux enhancement andquality control of the permeate (beer). Table 4 summarises themain studies published on this topic with the main processparameters utilised by the authors. Depending on the dataavailable, the Reynolds number is presented instead ofcross-flow velocity to make comparative analysis moremeaningful.

Burrell et al. (1994) used tubular ceramic membranes withnominal pore sizes of 0.5, 1.0, and 1.3 μm. The 0.5-μm-pore-size membrane displayed bright filtrates with no significantremoval of the desirable beer components, whereas the1.3-μm membranes produced filtrates of poorer quality.Similar results were presented by Gan et al. (1997, 2001)using ceramic membranes with pore sizes of 0.2, 0.5, and1.3 μm to clarify a cold-conditioned rough beer. Higher fluxeswere obtained with membranes of lower nominal pore sizeaccording to these authors. This result was attributed to thehigher-pore-size membranes being more affected by internalpore blockage by particles larger than 0.5 μm. However, thequality of the obtained permeate with lower pore size (0.2μm)was reduced due to the retention of proteins responsible forfoam stability.

The retention of macromolecules and finer colloids duringfiltration is responsible for a severe decrease in flux due tomembrane fouling. Fouling of membranes is cited by almostall researchers that study clarification of beer and hasbeen investigated extensively (Blanpain and Lalande1997; Blanpain-Avet et al. 1999a, b; Fillaudeau et al.2007; Gan 2001). Internal pore blockage, with conse-quent cake layer formation, was found to be the maincontributor to the increase of hydraulic resistance to flux.van der Sman et al. (2012) presented a complete review of thehypotheses for fouling formation during beer clarification

using membranes. For that reason, this topic is not reviewedin detail in this manuscript.

Different methods have been proposed to improve thepermeate flux, including the back flushing (BF) technique(Blanpain-Avet et al. 1999a, b; Gan 2001; Gan et al. 2001)and the more complex rotating and vibrating filtration (RVF)technique (Fillaudeau et al. 2007). These techniques promotehydrodynamic instabilities on the membrane surface, delayingthe formation of cake and fouling. Alternatively, Sensidoniet al. (2011) used a two-step process constituted by a prelim-inary treatment of the beer with enzymes (cellulase and pro-tease) and subsequent filtration through PES membranes witha nominal pore size of 0.45 μm. Their results confirmed thatexogenous enzymes degrade high-molecular-weight polysac-charides and proteins, improving beer flux and reducing fil-tration problems. However, the suspended particle size distri-bution was strongly modified, with a direct effect on productstability, specifically haze or precipitate formation.

Another important aspect of this issue is the use of mem-brane cleaning procedures to restore part of the permeate fluxfrom fouled membranes. Wenten et al. (1994) evaluated inter-nal and external cleaning procedures and found that a combi-nation of cleaning agents containing caustic and acid compo-nents restored the water permeabilities of ceramic and poly-meric membranes. However, a gradual decrease in the waterpermeability as a function of the number of cleaning cycles(72 for the ceramic and 36 for the polymeric) was observeddue to the modification of the surface chemistry for the ce-ramic membrane and the formation of scale on the polymericmembrane surface. Gan et al. (1999) observed a synergybetween the caustic cleaning and oxidation methods usingboth NaOH and H2O2 at 80 °C. A fast and effective single-step cleaning process was able to recover 87 % of the initialwater flux within 8 min of cleaning. In this context, ceramicmembranes have the advantage of being more resistant tochemicals and high temperatures, enabling harsh cleaning.Polymeric membranes, although less expensive, typicallyhave a short product life and limited resistance to changingtemperatures and chemicals (Stopka et al. 2000).

Examples of industrial systems for beer clarification usingmembranes are the Pentair BMF, with poly(ethersulphone)membranes of a 0.5-μm pore size and a filtration capacity of200 hL h−1 (Pentair 2012, 2013), and the Alfa-Laval/Sartorius cross-flow system, with poly(ethersulphone) mem-branes configured as cassette modules (Alfa-Laval 2003,2007).

Cold Sterilisation of Beer

Flavour instability and haze formation may occur during theproduct shelf life if the beer is not microbiologically stabilised.Pasteurisation is commonly used to ensure sterilisation of

Table 3 Classes of beer colloids reported by van der Sman et al. (2012)

Class Examples Typical size (μm)

Particles Yeast, clarification aids dp,1≈5Colloids Haze particles dp,2≈0.5–2.0Macromolecules Proteins, carbohydrates dp,3≈0.4

Numbers 1, 2, and 3 are used to identify/differentiate the class of beercolloids

dp particle diameter


beer, but this process requires heating, which acceleratesoxidation reactions and changes the beer character.

Cold sterilisation, also called sterile filtration, is an alterna-tive to pasteurisation. These processes can lead to a lowerdeployment cost and a fresher-tasting product, eliminating theorganoleptic problems induced by heating. Cartridge filtersare typically employed for sterile filtration, with the advantagethat the beer is inserted into a compact system very close to thepackage filling head, minimising the risk of recontaminationof the beer (Bamforth 2006).

Cold sterilisation is a potential market for CFMF. For thisproposal, MF must ensure the retention of beer-spoiling or-ganisms without removing essential beer constituents (Stewartet al. 1998). Membrane filters used as a final filtration stagecan have a pore size as low as 0.45 μm for the completeremoval of relevant bacteria, yeasts, and moulds, resulting inmicrobially stable beer with the longest possible shelf life.However, producing this beer requires more control to ensurea proper reduction in microbes and a smooth-operating bot-tling line (Starbard 2008). In addition, sterile filters are notabsolute filters and require a specification for the maximumconcentration of bacteria spoils and yeasts in the sterile-filtered beer (Priest and Stewart 2006). Studies on this subjecthave been conducted over the last two decades, as presented inTable 5, but the majority of these studies are more related tomembrane fouling and retention of beer components than tothe microorganism removal itself.

Stewart et al. (1998) used cold sterilisation to understandhow different beer constituents (β-glucan, arabinoxylan,protein, and polyphenol) that originated from barley malting

affect CFMF efficiency. The results from this study indicatedthat arabinoxylan and β-glucan strongly influence beer vis-cosity and reduce MF efficiency due to the increase of theviscosity. Polyphenols have the tendency to bind with proteinsand form larger particles, also decreasing MF efficiency.

Blanpain-Avet et al. (1999a, b) investigated membranefouling and protein rejection during CFMF of a clarified beerthrough 0.2 μm polycarbonate (PC) and aluminium oxide(ceramic) membranes. Even with different membrane charac-teristics (porosity and hydrophilicity), the permeate flux decayfor both membranes was governed by two successive foulingmechanisms caused mainly by protein–membrane interac-tions: internal pore fouling at the initial stages of filtration,followed by external surface fouling. The fouling layer wasresponsible for enhancing the protein rejection, and the rate ofpermeation as a function of time drastically decreased at theinitial phase of filtration, reaching a quasi-steady flux at asecond phase after approximately 20 min of permeation. Theinitial rate of flux decline was higher when higher pressurewas applied. These results indicate that operating at lower andconstant pressures would increase the process time due to lesscompaction of the solutes on the membrane surface.

However, even when the constant pressure condition isapplied, a decrease in the flux rate is observed. Thus, effortsto obtain higher and more stable fluxes are needed to expandthe use of MBSs in the brewing industry. In this sense, it isimportant to conduct studies on the specific characteristics ofindustrial membrane modules and the alternatives for operat-ing these modules. An example of this observation is theuniform transmembrane pressure (UTP) principle, whose

Table 4 Summary of works related to clarification of rough beer through microfiltration


Module Material Pore size (μm) TMP (atm) Temperature(°C)

Cross-flowvelocity(m s−1) orReynolds number

Tubular Ceramic 0.5, 1.0, and 1.3 0.8–3.75 <3 2 Burrell et al. (1994)

Tubular and capillary Ceramic and PES 1.0 (ceramic) 0.6(polymeric)

n.m. n.m. n.m. Wenten et al. (1994)

Tubular Ceramic 0.2, 0.5, and 1.3 0.35-0.93 <3 <0.75 Gan et al. (1997)

Flat disc PC Track-etched 0.2 0.1 and 1 0 Re=1,550–4,950 Blanpain and Lalande (1997)

Tubular Ceramic 0.5 0.8 <3 2 Gan et al. (1999)

Tubular Ceramic 0.14 0.1–0.8 20 1–5 Blanpain-Avet et al. (1999a, b)

Tubular Ceramic 0.2, 0.5, and 1.3 0.4, 0.8 and 1.2 2±0.9 Re =1,550 Gan et al. (2001)

Tubular Ceramic 0.5 0.8 2 Re=1,550–4,950 Gan (2001)

Tubular Ceramic 0.1, 0.45, 0.8, and1.4

0.2–2.0 −1–2.5 3–6 Fillaudeau and Carrère (2002)

Flat disc (RVF) Ceramic 0.6–4 <1 0–4 n.m. Fillaudeau et al. (2007)

Tubular Ceramic 0.45 0.5–2.7 0.5–9.6 0.15–1.02 Yazdanshenas et al. (2010)

Flat disc PES 0.45 0.7 2 n.m. Sensidoni et al. (2011)

TMP transmembrane pressure, n.m. not mentioned, RVF rotating and vibrating filtration


application in beer filtration has not yet been studied. TheUTP principle was developed by Sandblom (1978) to avoidthe variation of transmembrane pressure that occurs insidemembrane modules and along the length of the membrane,which leads to high fouling rates. In the UTP principle, thepermeate is recirculated on the permeate side of the membranein the same direction as the retentate flow, creating a pressuredrop corresponding to the flow direction of the filtrate thatmaintains a constant pressure difference between both sides ofthe filter throughout the entire filter area. This principle wasstudied in the filtration of dairy products with promisingresults (Hurt et al. 2010; Vadi and Rizvi 2001).

The porosity of membranes is also an important factor to beconsidered, as shown by Czekaj et al. (2000). Beer with a highmacromolecular concentration caused more severe fouling incellulose acetate (CA) membranes (with high surface porosi-ty) than in PC membranes (with low surface porosity), indi-cating that membrane morphology controlled fouling (Czekajet al. 2000).

Asano et al. (2007) demonstrated that the use of the0.65-μm-pore-size membrane was not able to retain beer-adapted microorganisms, and when the cold sterilisation ofbeer is the last barrier to beer contaminants, the evaluation ofmembrane filters should be carefully conducted by selectingappropriate test strains and preculture conditions (i.e. brewersshould select beer-spoilage strains common to the breweryenvironments to obtain a practical measure of their filterintegrity) as the physiological characteristics of spoilage con-taminants differ considerably between strains.

Low-Alcohol and Alcohol-Free Beer Production

The market for non-alcoholic beer has experienced a signifi-cant increase during the past few years, mainly because of newdriving/drinking rules and health and religious reasons(Catarino and Mendes 2011). Legal definitions of productsthat constitute a low-alcohol or alcohol-free beer vary fromcountry to country, but a low-alcohol beer typically has analcohol content of 0.5 to 1.2 %v/v, whereas an alcohol-freebeer should contain less than 0.5 %v/v of alcohol (Briggs et al.2004). Both beers can be produced either by biological or

physical routes. The former includes the use of special yeasts,arrested fermentation, and cold contact, whereas the latterincludes thermal processes and membrane processes(Almonacid et al. 2010; Brányik et al. 2012; Kosseva 2010;Montanari et al. 2009; Sohrabvandi et al. 2010). These tworoutes are more commonly known as manipulated fermenta-tion and alcohol separation after fermentation.

The biological method is the easiest way to produce low-alcohol or alcohol-free beer because no additional processsteps are required. Worts with low concentrations of ferment-able carbohydrates are utilised such that the fermentation stepproduces almost no ethanol (Montanari et al. 2009). Somedisadvantages of the biological method are a loss of flavoursand aroma compounds and a sweeter taste than conventionalbeers (Brányik et al. 2012; Catarino and Mendes 2011;Montanari et al. 2009). In the physical methods, of whichthermal is the most common, the alcohol is removed after thefermentation step, resulting in a product with characteristicssimilar to conventional beer. Although the thermal processeffectively reduces the alcohol content, this process is alsoknown to cause a deterioration of the beer quality, specificallya loss of flavours and liveliness.

Membrane processes provide interesting alternatives forseparating the alcohol after the fermentation process andinclude such advantages as lower energy consumption, nochemical additives, and operation at mild temperatures, there-fore reducing the impact of heat on the product. DI, RO, PV,and UF are the membrane techniques used in this field.However, to the authors' knowledge, the use of UF is men-tioned only in a U.S. patent for the production of a non-alcoholic malt beverage from concentrated beer (Tripp et al.1997). Thus, the three main membrane techniques found inthe production of low-alcohol beer are DI, RO, and PVfor the recovery of natural aroma compounds. The morerelevant works related to these techniques are summarisedin Table 6 and discussed separately in the followingsections.

Production of Low Alcohol Beer by Dialysis In the DI pro-cess, a concentration gradient induces the selective flux ofcomponents between two solutions of different compositions,

Table 5 Summary of works related to the cold sterilisation of beer through microfiltration


Module Material Pore size (μm) TMP (atm) Temperature (°C) Cross-flow velocity (m s−1)

Flat disc PA 0.45 2 4 n.m. Stewart et al. (1998)

Flat disc PC and ceramic 0.2 0.1–1 0 n.m. Blanpain-Avet et al. (1999a, b)

Flat disc PC and CA 0.22 0.79 23–25 n.m. Czekaj et al. (2000)

Flat sheet n.m. 0.65 n.m. n.m. n.m. Asano et al. (2007)

TMP transmembrane pressure, n.m. not mentioned


with the membrane acting as a molecular sieve permeableonly to certain molecules. The selectivity with relation to aspecific solute depends on the pore size and the surfaceproperties of the membrane. In the production of the low-alcohol beer, alcohol is abstracted from the beer into water byDI. Hollow fibre modules are more common for beer DI, butflat film or tubular DI materials may also be used. The prin-ciple of hollow fibre DI and a typical flow diagram of beerdealcoholisation by DI are shown in Fig. 2.

To maintain a low alcohol content in the dialysate, theethanol must be continuously removed (Briggs et al. 2004).However, all beer ingredients tend to move from the area ofhigh concentration (beer) to the area of low concentration

(water), whereas some water will diffuse from the dialysateto the beer (Brányik et al. 2012). The separation of alcoholfrom beer with DI occurs at low temperatures (1–6 °C),avoiding a thermal impact on the beer. However, losses oflow-molecular-weight volatile compounds (higher alcoholsand esters) to the dialysate solution must be considered. Atransmembrane pressure difference of less than 1 bar is oftenapplied to compensate for the osmotic pressure, to suppresstransport of water into the beer, and to enhance alcohol trans-port in the dialysate direction (Petkovska et al. 1997b).Petkovska et al. (1997b) demonstrated that the convectiveand diffusive flows take place simultaneously during theprocess; the diffusive component is of primary importance

Table 6 Summary of works related to beer dealcoholisation by dialysis and reverse osmosis and to the aroma recovery by pervaporation


Module Material Pore size TMP (atm) Temperature(°C)

Cross-flowvelocity (m s−1)

Dialysis

Hollow fibre Cellulose n.m. 0.1 5 n.m. Moonen and Niefind (1982)

Hollow fibre (DI and UF) Regenerated cellulose 500 Da 0–0.4 5 n.m. Petkovska et al. (1997a, b)PSf 5,000 Da 0–0.7 5

Reverse osmosis

n.m. Cellulosic and non-cellulosic materials

a 3.4–17 5–20 n.m. Light (1986) p

Spiral Cellulosic a 35–50 0 n.m. Pilipovik and Riverol (2005);

n.m. CA and PA a 15–45 5–20 n.m. Catarino et al. (2006, 2007)

Pervaporation

n.m. PDMS films andcomposite

a (5–10)×10−3 35–70 n.m. Brüschke (1990)

Plate and frame PDMS composite a 1×10−3 20 3.3 Karlsson and Tragardh (1996)

Flat sheet POMS/PEI composite a Permeate—1, 10.5,and 20×10−3

5, 10, and 15 0.1, 0.3, and 0.5 Catarino et al. (2009); Catarinoand Mendes (2011)

Retentate—2

TMP transmembrane pressure, n.m. not mentioned, p patenta Reverse osmosis and pervaporation membranes are not characterised according to pore size, as the selective layer is dense

Fig. 2 Flow diagram of beerdealcoholisation by dialysis,where: 1A—principle of hollowfibre dialysis; 1B—schematicrepresentation of capillarymembrane module; 2—heatexchanger; 3—stripper column;4—original beer; 5—dealcoholised beer; 6—dialysate;7—make-up brewing water; 8—glycol; 9—dialysate pump; 10—alcoholic condensate; 11—stripping steam. From Brányiket al. (2012)


for the elimination of alcohol molecules, whereas the convec-tive component plays an important role in the transport oflarge molecules.

A large-scale DI unit for beer dealcoholisation was pre-sented by Moonen and Niefind in 1982. The unit reduced thealcohol content of a beer from 5 to 3 % wt. without signifi-cantly affecting the chemical and physical stability of the beer(Moonen and Niefind 1982).

Regarding the type of membranes, several polymers havebeen used for the synthesis of DI membranes, includingcellulose, polyamides, polysulphone, polycarbonate, copoly-mers of acrylonitrile and vinyl chloride, polyacetal,polyacrylate, polyelectrolyte complexes, cross-linked polyvi-nyl alcohols, and acrylic copolymers, such as Nafion (deCastro et al. 2008). Porous hydrophilic membranes made ofcellulose (Cuprophane) are commercially available and are themost frequently used material for beverage dealcoholisationby DI (Barth 1989; Moonen and Niefind 1982; Tilgner andSchmitz 1987).

Production of Low-Alcohol Beer by Reverse Osmosis In theRO process, pressurised beer (20–80 bar) is put in contact witha semi-permeable membrane to promote the permeation ofalcohol and some water to the permeate side, whereas largermolecules, such as aroma and flavour compounds, virtuallyremain on the concentrated side. The amount of water lost istypically recovered and added to the feed or at the end ofprocess for adjustment of the ethanol content in the product.Permeate flux (water, ethanol, and aroma compounds) in-creases with the increase of pressure and temperature, andhigh flow rates must be used to reduce concentrationpolarisation (Catarino et al. 2007).

The use of two stages was proposed to reduce the alcoholiccontents of a beer from 4 to 1 %v/v, with each stage beingresponsible for removing 50 % of the initial alcohol content(Light et al. 1986; Light 1986). Pilipovik and Riverol (2005)and Catarino et al. (2006, 2007) demonstrated that the mini-mum alcohol content of a dealcoholised beer obtained by ROis approximately 0.5 %v/v using the diafiltration mode, whichconsists of adding demineralised water or the recovered pro-cess water to the concentrated beer to wash ethanol out of thebeer, reducing the alcohol content to the desired value. Afterthe diafiltration, the beer can be still adjusted to a loweralcohol content or fine-tuned to taste by adding moredemineralised water (Brányik et al. 2012).

Figure 3 illustrates a flow chart of the RO system used toremove alcohol from beer.

The membranes used in this application are generallyasymmetric in structure, with an active layer made of celluloseacetate, polyamide, or polyimide, and are placed in modulesof different geometric arrangements (e.g., planar, tubular,spiral wound) (Light et al. 1986). In fact, a high loss ofvolatiles (70–80 % of higher alcohols, 80–90 % of esters)

during the process was reported byKavanagh et al. (1991) andStein (1993) and was attributed to the imperfect selectivity ofmembranes (Brányik et al. 2012). In such a case, flavouringcompounds may be added to the processed beer to improvebeer characteristics after dealcoholisation. These compoundscan be obtained by a primary extraction from the beer itselfbefore the dealcoholisation process, as discussed in the nextsection.

In comparison with DI, the use of RO for ethanol removalfrom beer may present some problems related to the use ofhigh pressures. High energy consumption is one problem thatmay raise the costs of production. High-pressure pumpingalso increases the temperature of beer, requiring cooling sys-tems to maintain the temperature at an acceptable level.During the dealcoholisation process, the concentration of thebeer components may lead to membrane fouling, reducing themembrane permeability. Another disadvantage is the perme-ation of the carbon dioxide (CO2) dissolved in beer, whichmust be re-injected to the desired level (Priest and Stewart2006).

In DI, the pressures required are much lower, limiting theneed for expensive pumps. Even CO2 remains dissolved,decreasing the amount of CO2 required to carbonate the beer.However, the porous nature of the DI membranes allows forthe permeation of compounds with higher molecular weightsthan those that can permeate through the ROmembranes, alsoimpacting the beer structure. If a process step to regenerate thedialysate is considered, the process may also have high energyconsumption.

Recovery of Natural Aroma Compounds by Pervaporation

The loss of aroma and flavour compounds during thedealcoholisation process decreases the quality of the finalproduct, mainly because some of the volatile aroma com-pounds are removed together with ethanol. Aroma recovery

Fig. 3 Typical flow chart of a beer dealcoholisation process by reverseosmosis


by distillation, evaporation, condensation, and gas injectiontechniques may be employed, as presented by Karlsson andTragardh (1996), but these processes are labour intensive andmay thermally impact the aroma compounds. The extractionof aroma compounds from the original beer before thedealcoholisation and their subsequent addition back to thedealcoholised beer has proven effective with the PV technique(Catarino et al. 2009; Catarino and Mendes 2011).

PV is a process in which a liquid feed contacts one side of amembrane and permeate is removed as a vapour from theother side. Transport through the membrane is induced bythe vapour pressure difference between the feed solution andpermeate vapour; the vapour pressure difference is typicallyobtained by applying a vacuum on the permeate side whilecondensing this side by cooling (Baker 2004).

PV has been studied for the aroma recovery from beer,wines, and juices with positive results (Diban et al. 2008; Hoand Sheridan 2002; Karlsson and Tragardh 1996; Tan et al.2005) and was also studied for the dealcoholisation of beer(Brüschke 1990). Brüschke (1990) used PV as a first step torecover aroma compounds for later reinjection in the final beerand as a second step to remove ethanol to a final concentrationlower than 0.5 %v/v. When the ethanol content was reduced toapproximately 90 %, all of the esters were completely re-moved, and the higher alcohols were reduced to the samelevel as ethanol and the acids were reduced to approximately60 %.

Catarino et al. (2009) investigated the effect of operatingconditions on the performance of the recovery of aromacompounds before beer dealcoholisation. These authors foundthat the permeate flux increases linearly with the temperatureand increases slightly with the feed velocity while diminishingwith an increase in permeate pressure. The selectivities of thearoma compounds against ethanol were affected by the oper-ating conditions. By increasing the temperature, the highalcohol selectivity is increased due to the higher transportactivation energy of alcohols compared to water, whereasthe selectivities of the esters decreased due to the similartransport activation energies of esters and water. The increasein the feed velocity leads to a higher increase in the esterselectivity than in the higher alcohol selectivity due to theinfluence of concentration polarisation effects. An increase inthe permeate pressure results in a decreased high alcoholselectivity due to the lower saturation vapour pressures ofthese alcohols, whereas the ester selectivity increases.

A schematic block diagram of a dealcoholisation processcontaining a PVunit for aroma recovery is shown in Fig. 4. Inthe first step of the process, a stream fraction of non-carbonated alcoholic beer is pervaporated to extract the aromacompounds. The retentate stream of this PV unit is added tothe other fraction of alcoholic beer to feed the dealcoholisationunit. Finally, the dealcoholised beer is blended with the ex-tracted aroma compounds (approximately 0.3 vol.%) from the

PV unit and a fraction of fresh alcoholic beer (5–10 vol.%) tobalance the aroma profile (Catarino and Mendes 2011).

Gasification and Degasification of Beer

Themain goal of beer gasification is the formation of the foamhead when the beer is served. The foam head acts as a gasexchange surface, pitching aromas toward the drinker’s olfac-tory sensors that provide the first contact with the quality ofthe beer in terms of flavour and freshness (Bamforth 2008;Delvaux et al. 1995). CO2 is the most common gas used in thegasification of beer, in a process known as carbonation. Aportion of the required CO2 can be obtained from a secondaryfermentation in a closed tank, in which the beer remains for anappropriate time, with the produced CO2 dissolving in thesolution. Drawbacks of this method include the CO2 concen-tration variability from batch to batch, the influence of pres-sure on yeast growth, and some changes in the flavour char-acteristics of the beer (Priest and Stewart 2006). Moderncarbonation systems use a carbonation stone to produce finebubbles, which are dispersed into beer until the CO2 concen-tration reaches a specified value. Over carbonation must becarefully controlled when using this method.

Nitrogen is typically used in conjunction with CO2 togasify keg-conditioned beers when these beers are sold ontap at a bar or restaurant. The gas mixture creates a “smoother”beer, with a creamier and more consistent head, due to thelower partial pressure of nitrogen, which produces smallerbubbles than CO2. Nitrogenation is also a practice in industrythat uses the same carbonation stones to inject nitrogen intothe beer. A disadvantage of this method is that the directinjection may drag the CO2 out of the beer, requiring moretime and expense with gasification.

Membrane contactors have been used for the gasification/degasification of beer in a process called non-dispersive dif-fusion (BRAUWELT 2000; Drioli and Fontananova 2004).Membrane contactors are devices that allow a gaseous phaseand liquid phase to come into direct contact with each otherfor the purpose of mass transfer between these phases withoutdispersing one phase into the other. CO2 is removed from beerto some extent, and nitrogen is continuously transferred to thebeer. The process can also be used to increase the amount ofCO2 if this component is below the specified value(BRAUWELT 2000).

Membrane-Based Systems as an Additional Step in ParticularBrewery Operations

Recovery of Beer and Yeast

Two fermentation steps are typically used to produce beer.The first step is finished when approximately 90 % of thefermentable matter is consumed; the fermentation is stopped


by rapidly cooling the tank of beer, reducing the yeast activity,and promoting the sedimentation of yeast, along with theflocculation of other insoluble particles. After the first fermen-tation, the beer is called “green beer”, and the bottom tank hasa high yeast cell content and high viscosity. In the second step,the beer is generally transferred to another tank to mature andproduce part of the carbonation that will remain in the beer,where new sedimentation occurs. After maturation, the beer iscalled “rough beer”, and the tank bottom has high contents ofprotein and polyphenols, fewer yeast cells, and low viscosity(Daufin et al. 2001).

The production of the green and rough beer and yeastrecovery may be carried out using natural sedimentation orcentrifugation, but microfiltration is almost an industrial stan-dard. Microfiltration of tank bottoms allows for the recoveryof almost 5 % of the produced beer; green beer is responsiblefor approximately 1–2 % and may be recycled in the wort ormaturation vessel, whereas the recovered rough beer repre-sents approximately 1.5–3 % and may be returned to thematuration vessel or sent to the final clarification (Daufinet al. 2001).

In the beer/yeast recovery operation from tank bottoms, themicrofiltration process aims to concentrate the high solidcontent fluid (approximately 10 %) to more than 20 % ofsolids. If subsequent filtration steps will be used to clarify and/or sterilise the beer, using membranes with more open pores ispreferred to recover the beer, allowing for higher fluxes andeconomic benefits. Tank bottoms microfiltration typically re-quires membranes with a 1.0–2.0-μm pore size. As observedin other applications, ceramic membranes are preferred due totheir longer useful life. However, the use of polymeric mem-branes, although being less resistant to chemical cleaning, isgrowing in importance because of their lower prices and thecontinuous developments in this field.

The tank bottom filtration with ceramic membranes hasbeen studied by several authors, with most of the observationsindicating, as expected, that increases in pore sizes lead toimproved rough beer filtration rates and declining clarity.

O’Reilly et al. (1987) obtained filtrate hazes of 0.5–2.5 SRMwith membranes of 1.8 μm. Using ceramic membranes with a0.2-μm pore size, Esslinger (1990) obtained sterile filtratesbut also removed high-molecular-weight components. Burrellet al. (1994) tested membranes of 0.5, 1.0, and 1.3 μm andobserved that the 1.3-μmmembrane provided the highest beerfluxes, but with significant losses of beer components. Withrespect to the influence of the initial solid content on filtrationperformance, filtration of tank bottoms with less than 1 % dryweight resulted in high filtrate hazes, 0.75–2.75 SRM, where-as filtration of tank bottoms with more than 1 % dry weightresulted in greater clarity of the filtrate, presumably becausethe fouling layer acted as a secondary membrane of smallerpore size (Burrell et al. 1994; Murkes 1986).

van Rijn et al. (1997) presented the recovery of yeast/beerusing microsieve membranes with an industrial case fromGrolsch breweries. A permeate flux of 4,000 L m−2 h−1 wasobtained during a period of at least 5 h without any increase inthe transmembrane pressure. This permeate flux is higher thanthose obtained with other membranes. However, fouling ofthe microsieve membranes by yeast cells was also observedby Kuiper et al. (2002) using membranes with pores of 0.8–1.5 μm to filter a lager beer. The authors verified that otherbeer components, such as proteins, were responsible forblocking the membrane pores, creating a fouling layer alongwith the yeasts on the membrane surface.

Examples of industrial applications include (1) the GEAWestfalia PROFI, which combines centrifugation, decanta-tion, and filtration through ceramic membranes (GEA 2009,2013); (2) the Pall Keraflux technology, in which multi-channel ceramic membranes with a 0.8-μm pore size are usedto concentrate surplus yeast up to a concentration of 20% w/wwith a transmembrane pressure up to 3 bar (Bock and Oechsle1999; Pall 2013); and (3) the Alfa-Laval BeerRecover AL,with 0.45-μm-pore PVDF membranes (Alfa-Laval 2013).

The brewer’s spent yeast (BSY) generated in the fermen-tation and maturation stages represents the other major by-product from the brewing industry. This yeast is sold primarily

Fig. 4 Block diagram of theindustrial process for producingnon-alcoholic beer, where theflavour compound is recoveredby PV. Adapted from Catarinoand Mendes (2011)


as inexpensive animal feed after inactivation by heat, andmuch of this by-product is considered industrial waste(Shotipruk et al. 2005). The reuse of part of the yeast extractin subsequent fermentations is also a common procedurecarried out in a brewery for economic reasons and/or tomaintain the same strains for several generations. The BSYbiomass presents several properties (high levels of proteins,vitamin B complexes, and minerals) that make this yeastoutstanding for industrial use and a potential source of nutri-ents for human or animal nutrition, microbial growth, andenzyme extraction (Ferreira et al. 2010).

Matsumoto et al. (1987) studied the concentration of yeastfrom fermentation broths and yeast suspensions using cellu-lose triacetate membranes with a 0.45-μm pore size.Operation pressure and fermentation conditions (initial yeastconcentration) affected the filtration behaviour, and foulingwas controlled by backwashing with the filtrate for 5 s every5 min of operation, maintaining a constant permeate flux for3 h.

Shotipruk et al. (2005) used ceramic membranes with a0.2-μm nominal pore size in a rotary microfiltration to com-bine debittering and cell debris separation to produce a yeastextract from BSY. In the rotary microfiltration, the centrifugalforces on the fluid give rise to Taylor vortices, which arethought to reduce the accumulation of a fouling layer on themembrane surface. The results demonstrated that the permeateflux increased with an increase of the rotational speed due tothe increased shear rate. However, the debittering efficiencyalso decreased, reducing the quality of the product obtained(Shotipruk et al. 2005).

New Trends for the Use of Membrane SeparationProcesses in the Brewery

For hundreds of years, the brewing industry has been a tradi-tional industry with traditional processes and techniques. Forbrewers to maintain their competitiveness, any reduction incosts, such as minimising water and energy consumption, andreduction in wastewater generation constitute a real gain forthe balance sheet. However, those opportunities are limitedwhen considering traditional processes.

In this sense, aside from the established applicationsdiscussed previously, membrane separation processes exhibitother potential uses in the brewery that may enhance breweryyield. These uses include the recovery of beer and by-productsand the reduction of waste generation, with a consequentreduction of losses and environmental impacts.

Extract Recovery from Hot Trub

During wort boiling, tannins extracted from the malt andadded hops promote the coagulation of the protein extracted

from the malt. Hop particles, the coagulated proteins, andsimpler nitrogenous constituents that interact with carbohy-drates and polyphenols precipitate, forming a slurry called hottrub or hot break (Magalhães et al. 2008). Separation of the hottrub from the wort is a common practice by using the whirl-pool system. However, the wort losses in this system aresubstantial, particularly in large breweries. Further, the trubcone generated by the whirlpool often collapses when the wortis drained, causing residual turbidity of the clarified wort.Centrifugation is an alternative option, but this process hashigh cost and energy consumption (Barchet 1993).

The hot trub particle size varies widely depending on theraw materials and brewing process utilised, but this size isexpected to be in the range of 0.5-500 μm (Montanari et al.2009). Therefore, CFMF would allow for the recovery ofhigh-quality wort from hot trub, although no scientific orindustrial data on this subject have been reported to date.The wide range of particle sizes, the probable fouling prob-lems, and the high wort temperature may be limiting factors tothe use of membrane-based systems for this application.

Extract Recovery from Cold Trub

Wort cooling before fermentation also leads to the formationof insoluble matter composed of proteins, protein-polyphenolcomplexes, and carbohydrates. This insoluble matter is calledcold trub or cold break (Bamforth 2003; Barchet 1994). Themanner in which cold trub removal affects the characteristicsof beer depends on the yeast strain, the number of yeastgenerations used, the method and amount of removal, andthe overall brewery characteristics. Although different opin-ions exist regarding removing the cold trub, there is a consen-sus that the removal of at least some of the cold trub improvesthe yeast viability and finished beer quality, reducing hazecomponents (Barchet 1994).

Settling tank, flotation, and centrifugation are somemethods used to promote the removal of cold trub (Barchet1994). CFMF would also be an interesting alternative.However, the implications of the higher viscosity of the wortand the smaller particle size compared to the hot wort must beevaluated.

Recovery of Carbon Dioxide from Fermentation

The CO2 produced in the fermentation step does not constitutean environmental problem. Because barley crops are renew-able, the released CO2 is not an addition to the greenhousegases in the atmosphere. However, the recovery of this green-house gas may represent an attractive operation from aneconomic point of view because nearly all breweries useCO2 for final product carbonation, tank blanketing, air remov-al, purging of lines, and packing operations (Priest andStewart 2006; Starbard 2008). In such cases, care must be


taken in the collection, purification, and storage of the gas aspotential contamination sources are associated with gas stor-age, final delivery to the plant, and point of use (Starbard2008).

Another important aspect is that the introduction of anyoxygen into the beer is also unacceptable, and thus, the CO2

used in the process must contain as little oxygen as possible.Large breweries commonly coordinate the CO2 collectiontime with the fermentation cycle to minimise the oxygencontent after the presence of oxygen is reduced by yeastmetabolism during fermentation. The purification is carriedout through adsorption columns with activated carbon anddryers, which remove the gaseous impurities (organics andsulphur compounds), and through compression/liquefactionof the impure CO2, removing some of the non-condensablegases (oxygen and nitrogen) (GEA 2012; Mellcom 2012;P e r r y and Co l eman 1987 ; Wi t t emann 2012 ) .Microbiological contamination is typically avoided by usingsterile filtration with hydrophobic PTFE cartridge membraneswith a nominal pore size of 0.2 μm.

The amount of CO2 generated in the fermentation step maybe sufficient to meet the total demand of a brewery and evenleave some surplus for sale. However, with current systems,the recovery operation provides a yield of only approximately60% due to losses and cleaning of the gas (Briggs et al. 2004).Gas separation by membranes appears to be an appropriatealternative for separating organic/permanent gases and sul-phur compounds from CO2. A membrane separation processrequires far less maintenance and energy consumption than acomparable absorption process for the purification of concen-trated CO2 streams. A membrane material that either allowsfor the selective transport (diffusion) or selective exclusion ofCO2 is desired (Granite and O’Brien 2005).

Numerous studies considered the separation of CO2 fromother gaseous streams, as in natural gas purification (Echt andMeister 2009; Rufford et al. 2012; Yeo et al. 2012) and CO2

capture and storage (CCS) due to global warming concerns(Brunetti et al. 2010; Favre 2007; Yang et al. 2008). To theauthors’ knowledge, no work has been published to dateregarding a membrane-based system for CO2 purificationfrom fermentation processes.

Capturing CO2 from a fermentation process may be com-pared to the post-combustion approach (from CCS), in whicha flue gas is directly treated after the combustion step.According to Favre (2007), membranes may compete withtraditional techniques in terms of energy requirements as soonas CO2 content in the post combustion feed mixture exceeds20 %, a level that is easily reached after several hours offermentation.

The gas temperature at the end of the fermentation step is inthe range of 8–22 °C (limits for fermentations of lager and alebeers), which is compatible with the operation conditions ofmembrane processes. However, pressurisation of the gas

stream would be required to obtain an adequate driving force.Limitations may occur with the presence of other gases gen-erated during the fermentation, which may have a stronginfluence on the separation. Volatile organic compounds(VOCs) and hydrogen sulphide (a common by-product ofyeast) will be present in the fermentation tank. As the CO2

becomes more concentrated and the target compound is ob-tained, maintaining this compound on the concentrated andpressurised side of the membrane is preferable, whereas theother gases must permeate through the membrane. Siliconrubber is a well-known material used to synthesise mem-branes for VOC recovery from permanent gas streams(Khan and Ghoshal 2000; Ohlrogge et al. 2010) and couldbe used for CO2 recovery from beer fermentation vessels.

Concluding Remarks

Membrane separation processes are becoming increasinglycompetitive compared to other traditional technologies.Aside from such advantages as energy economy and wide-ranging applications, the modular design and easier operationenable continuous operation, which may be a future alterna-tive for the brewing industry to reduce costs and sustainmarket competitiveness.

The use of additives to promote beer clarification andimprove beer stability is minimised or even eliminated, asmembranes are able to produce very clear, sterilised, andstable beer. The resources spent on disposal costs and effluenttreatment may also be diminished once the waste streamvolumes are reduced.

The use of membrane techniques is not restricted to thebrewery itself but is instead also applicable to water treatmentand wastewater/effluent treatment. RO is increasingly used forwater treatment to produce brewery water, allowing the brew-eries to tailor-make their water for different products, increas-ing flexibility in the industry. The brewing industry is one ofthe largest wastewater producers; thus, the search for newtechnologies for the treatment of these streams is not merelyan option but also an obligation. The use of membrane pro-cesses in wastewater treatment may enable the reuse of waterstreams, reducing the acquisition of water and the increasingassociated costs.

Nevertheless, potential contributions to the further progressof membrane technology in the brewery industry are diverseand significant. The overall performances of membranes sys-tems are determined by membrane selectivity and permeatefluxes, which are dependent on operating conditions andmembrane characteristics. The development of new mem-branes with characteristics specific to the beer process, mod-ules with designed spacers and operating conditions to mini-mise concentration polarisation and the tendency to foul arealso essential. Hybrid processes with traditional techniques


andmembranes are relatively unexplored but may be econom-ic alternatives in the near future. To minimise project errorsand obtain the best results, these properties must be welldefined by bench-scale experiments, evaluating the needs foreach specific case.

Finally, the brewing steps and the membrane applicationspresented here may change considerably with the size ofbrewery, the type of beer produced, and the goals of thecompany. A detailed technical, qualitative, and economicanalysis of the potential of this technology, mainly related tobeer quality standards, is mandatory for the successful use ofmembrane technology.

Acknowledgements The authors thank the National Council for Sci-entific and Technological Development (CNPq), the Coordination for theImprovement of Higher Level Personnel (CAPES), and the ResearchSupport Foundation of the State of Rio Grande do Sul (FAPERGS) ofBrazil.

References

Alfa-Laval. (2003). Innovation in beer filtration gathers momentum.Lund, Sweden. Retrieved from http://www.alfalaval.com/about-us/press/product-press/Documents/071106_cross_flow_en.pdf

Alfa-Laval. (2007). Top end beer from cross-flow filters. Filtration &Separation, 44(2), 40–41. Retrieved from http://www.sciencedirect.com/science/article/pii/S0015188207700575.

Alfa-Laval. (2013). Alfa Laval beer recovery system. Alfa-Laval.Retrieved from http://www.alfalaval.com/solution-finder/products/membrane-filtration-systems/Documents/PCM00069EN_LOWRES_beer recovery.pdf

Almonacid, S. F., Nájera, A. L., Young, M. E., Simpson, R. J., &Acevedo, C. A. (2010). A comparative study of stout beer batchfermentation using free and microencapsulated yeasts. Food andBioprocess Technology, 5(2), 750–758.

Asano, S., Suzuki, K., Iijima, K., Motoyama, Y., Kuriyama, H., &Kitagawa, Y. (2007). Effects of morphological changes in beer-spoilage lactic acid bacteria on membrane filtration in breweries.Journal of Bioscience and Bioengineering, 104(4), 334–338.

Baker, R. W. (2004).Membrane technology and applications (2nd ed., p.545). Chichester, England: Wiley.

Bamforth, C. W. (2003). Beer—tap into the art and science of brewing(2nd edition, p. 246). New York: Oxford University Press Inc.

Bamforth, C. W. (2006). Brewing: new technologies. (C. W. Bamforth,Ed.) (p. 501). Boca Raton: CRC Press Inc.

Bamforth, C. W. (2008). Beer: a quality perspective (Handbook ofAlcoholic Beverages). (I. Russel, C. W. Bamforth, & G. G. Stewart,Eds.) (1st Edition, p. 287). California: Academic Press.

Barchet, R. (1993). Hot trub, formation and removal. BrewingTechniques, 1(4). Retrieved from http://morebeer.com/brewingtechniques/library/backissues/issue1.4/barchet.html

Barchet, R. (1994). Cold trub: implications for finished beer and methodsof removal. Brewing Techniques, 2(2).

Barth, N. (1989). Process for the production of fermented drinks withreduced alcohol content. US patent No 4804554.

Benítez, E. I., Amezaga, N. M. J. M., Sosa, G. L., Peruchena, N. M., &Lozano, J. E. (2013). Turbidimetric behavior of colloidal particles inbeer before filtration process. Food and Bioprocess Technology,6(4), 1082–1090.

Blanpain, P., & Lalande, M. (1997). Investigation of fouling mechanismsgoverning permeate flux in the crossflow microfiltration of beer.Filtration and Separation, 34(10), 1065–1069.

Blanpain-Avet, P., Doubrovine, N., Lafforgue, C., & Lalande, M.(1999a). The effect of oscillatory flow on crossflow microfiltrationof beer in a tubular mineral membrane system—membrane foulingresistance decrease and energetic considerations. Journal ofMembrane Science, 152(2), 151–174.

Blanpain-Avet, P., Fillaudeau, L., & Lalande, M. (1999b). Investigationofmechanisms governingmembrane fouling and protein rejection inthe sterile microfiltration of beer with an organic membrane. Foodand Bioproducts Processing, 77(2), 75–89.

BMG. (2011). World beer production increased again in 2010. (B.Manager, Ed.). Beverage Manager. Retrieved August 28, 2013,from http://beveragemanager.net

Bock, M., & Oechsle, D. (1999). Beer recovery from spent yeast withKeraflux membranes. The Brewer, 85(7), 340–345.

Brányik, T., Silva, D. P., Baszczynski, M., Lehnert, R., & Almeida eSilva, J. B. (2012). A review of methods of low alcohol and alcohol-free beer production. Journal of Food Engineering, 108(4), 493–506.

BRAUWELT. (2000). Non-dispersive diffusion for nitrogenation.Brauwelt International.

Briggs, D. E., Boulton, C. A., Brookes, P. A., & Stevens, R. (2004).Brewing: science and practice (1st edition, p. 864). Boca Raton:CRC Press Inc.

Brunetti, A., Scura, F., Barbieri, G., & Drioli, E. (2010). Membranetechnologies for CO2 separation. Journal of Membrane Science,359(1–2), 115–125.

Brüschke, H. E. A. (1990). Removal of ethanol from aqueous streams bypervaporation. Desalination, 77, 323–330.

Bühler, T., Burell, K., Eggars, H. U., Reed, R. J. R., & Olajire, A. A.(1993). The application of membranes for new approach to breweryoperations. In European Brewing Convention Congress (pp. 691–700). Olso: Oxford.

Burrell, K. J., Reed, R. J. R., Burrell, B. K. J., Hall, L., & Road,H. (1994). Crossflow microfiltration of beer: laboratory-scalestudies on the effect of pore size. Filtration and Separation,31(4), 399–406.

Catarino, M., & Mendes, A. (2011). Non-alcoholic beer—a new indus-trial process. Separation and Purification Technology, 79(3), 342–351.

Catarino, M., Mendes, A., Madeira, L., & Ferreira, A. (2006).Beer dealcoholization by reverse osmosis. Desalination, 200,397–399.

Catarino,M., Mendes, A.,Madeira, L. M., & Ferreira, A. (2007). Alcoholremoval from beer by reverse osmosis. Separation Science andTechnology, 42(13), 3011–3027.

Catarino, M., Ferreira, A., & Mendes, A. (2009). Study and optimizationof aroma recovery from beer by pervaporation. Journal ofMembrane Science, 341(1–2), 51–59.

Czekaj, P., López, F., & Güell, C. (2000). Membrane fouling duringmicrofiltration of fermented beverages. Journal of MembraneScience, 166(2), 199–212.

Daoud, I. (1985). Crossflow filtration: an alternative for mash separation.Brewing and Distilling International, 23(5), 31–32.

Daoud, I. (1989). Separation of wort from mash. US patent No 4844932.Daoud, I. (1992). Crossflow filtration: an alternativemash separation. The

Brewhouse BDI, 5, 18–19.Daufin, G., Escudier, J. P., Carrère, H., Bérot, S., Fillaudeau, L., Decloux,

M., … Carre, H. (2001). Recent and emerging applications ofmembrane processes in the food and dairy industry. Institution ofChemical Engineers, 79(June), 89–102.

De Castro, M. D. L., Capote, F. P., & Ávila, N. S. (2008). Is dialysis aliveas a membrane-based separation technique? TrAC - Trends inAnalytical Chemistry, 27(4), 315–326.


http://www.alfalaval.com/about-us/press/product-press/Documents/071106_cross_flow_en.pdf

http://www.alfalaval.com/about-us/press/product-press/Documents/071106_cross_flow_en.pdf

http://www.sciencedirect.com/science/article/pii/S0015188207700575

http://www.sciencedirect.com/science/article/pii/S0015188207700575

http://www.alfalaval.com/solution-finder/products/membrane-filtration-systems/Documents/PCM00069EN_LOWRES_beer



http://morebeer.com/brewingtechniques/library/backissues/issue1.4/barchet.html

http://morebeer.com/brewingtechniques/library/backissues/issue1.4/barchet.html

http://beveragemanager.net

Delvaux, F., Deams, V., Vanmachelen, H., Neven, H., & Derdelinckx, G.(1995). Retention of beer flavours by the choice of appropriate glass.Proceedings of the EBC Congress, 25, 533–542.

Diban, N., Urtiaga, A., &Ortiz, I. (2008). Recovery of key components ofbilberry aroma using a commercial pervaporation membrane.Desalination, 224(1–3), 34–39.

Drioli, E., & Fontananova, E. (2004). Membrane technology and sustain-able growth. Chemical Engineering Research and Design, 82(12),1557–1562.

Echt, W., & Meister, P. (2009). Design, fabrication and startup of anoffshore membrane CO2 removal system . (G. P. Association,Ed.)88th Annual Convention - UOP LLC. Gas ProcessorsAssociation.

Esslinger, H. M. (1990). Technological evaluation of various methods forrecovering beer from spent yeast. In E. B. Convention (Ed.),Proceedings of European Brewing Convention (pp. 140–150).Leuven - Belgium: The Brewers of Europe.

Eumann, M., & Schildbach, S. (2012). 125th Anniversary Review: watersources and treatment in brewing. Journal of the Institute ofBrewing, 118(1), 12–21. doi:10.1002/jib.18.

Favre, E. (2007). Carbon dioxide recovery from post-combustion pro-cesses: can gas permeation membranes compete with absorption?Journal of Membrane Science, 294, 50–59.

Ferreira, I. M. P. L. V. O., Pinho, O., Vieira, E., & Tavarela, J. G. (2010).Brewer’s Saccharomyces yeast biomass: characteristics and poten-tial applications. Trends in Food Science and Technology, 21(2), 77–84.

Fillaudeau, L., & Carrère, H. (2002). Yeast cells, beer composition andmean pore diameter impacts on fouling and retention during cross-flow filtration of beer with ceramic membranes. Journal ofMembrane Science, 196(1), 39–57.

Fillaudeau, L., Blanpain-Avet, P., &Daufin, G. (2006).Water, wastewaterand waste management in brewing industries. Journal of CleanerProduction, 14(5), 463–471.

Fillaudeau, L., Boissier, B., Moreau, A., Blanpain-avet, P., Ermolaev, S.,Jitariouk, N., et al. (2007). Investigation of rotating and vibratingfiltration for clarification of rough beer. Journal of FoodEngineering, 80(1), 206–217.

Galitsky, C., Martin, N., Worrell, E., Lehman, B., & Worrel, E. (2003).Energy efficiency improvement and cost saving opportunities forbreweries (p. 74). Berkeley: University of California.

Gan, Q. (2001). Beer clarification by cross-flowmicrofiltration—effect ofsurface hydrodynamics and reversed membrane morphology.Chemical Engineering and Processing Process Intensification,40(5), 413–419.

Gan, Q., Field, R.W.,McKechnie, M. T., Shaughnessy, C. L. O., Bird,M.R., England, R.,… O’Shaughnessy, C. L. (1997). Beer clarificationby cross-flow microfiltration: fouling mechanisms and flux en-hancement. Institution of Chemical Engineers, 75(1), 6.

Gan, Q., Howell, J. A., Field, R. W., England, R., Bird, M. R., &McKechinie, M. T. (1999). Synergetic cleaning procedure for aceramic membrane fouled by beer microfiltration. Journal ofMembrane Science, 155(2), 277–289.

Gan, Q., Howell, J. . A., Field, R. . W., England, R., Bird, M. . R.,O’Shaughnessy, C. L.,… O’Shaughnessy, C. . (2001). Beer clarifi-cation by microfiltration—product quality control and fractionationof particles and macromolecules. Journal of Membrane Science,194(2), 185–196.

GEA. (2009). 100 Years Beer Separation with GEAWestfalia Separator.GEAWestfalia Separator Division. GEAWestfalia Separator Gmbh.Retrieved from http://www.westfalia-separator.com/fileadmin/Media/PDFs/Digest/SeparatorsDigest-2009-3-EN-100-Years-beer-separation.pdf.

GEA. (2012). CO2 recovery: Simple application—double profit.Kitzingen—Germany: GEA Process Engineering. Retrievedfrom http://www.geabrewery.com/geabrewery/cmsresources.

nsf/filenames/Refrigeration_E_0712.pdf/$file/Refrigeration_E_0712.pdf.

GEA. (2013). Systems and processes in breweries. GEA WestfaliaSeparator Division. Oelde. Retrieved from http://www.westfalia-separator.com/fileadmin/Media/PDFs/Brochures/Breweries-BE-12-10-0004.pdf.

Granite, E. J., & O’Brien, T. (2005). Review of novel methods for carbondioxide separation from flue and fuel gases. Fuel ProcessingTechnology, 86(14–15), 1423–1434.

Gupta, M., Abu-Ghannam, N., & Gallaghar, E. (2010). Barley forbrewing: characteristic changes during malting, brewing and appli-cations of its by-products. Comprehensive Reviews in Food Scienceand Food Safety, 9(3), 318–328.

Ho, S. V, & Sheridan, P. W. (2002). Membrane process for makingenhanced flavor fluids. US patent No 6419829.

Hurt, E., Zulewska, J., Newbold,M., & Barbano, D.M. (2010, December1). Micellar casein concentrate production with a 3X, 3-stage, uni-form transmembrane pressure ceramic membrane process at 50°C1.Journal of Dairy Science. American Dairy Science Association.

Karlsson, H. O. E., & Tragardh, G. (1996). Applications of pervaporationin food processing. Trends in Food Science and Technology, 7(3),78–83.

Kavanagh, T. E., Clarke, B. J., Gee, P. S., Miles, M., & Nicholson, B. N.(1991). Volatile flavor compounds in low alcohol beers. TechnicalQuarterly—Master Brewers Association of the Americas, 28(3),111–118.

Khan, F. I., & Ghoshal, A. K. (2000). Removal of volatile organiccompounds from polluted air. Journal of Loss Prevention in theProcess Industries, 13(6), 527–545.

Kosseva, M. R. (2010). Immobilization of microbial cells in food fer-mentation processes. Food and Bioprocess Technology, 4(6), 1089–1118.

Kuiper, S., van Rijn, C., Nijdam, W., Raspe, O., van Wolferen, H.,Krijnen, G., et al. (2002). Filtration of lager beer with microsieves:flux, permeate haze and in-line microscope observations. Journal ofMembrane Science, 196(2), 159–170.

Light, W. G. (1986). Continuous recycling process for the production oflow alcoholic beverages. US patent No 4617127.

Light, W. G., Mooney, L. A., Chu, H. C., &Wood, S. K. (1986). Alcoholremoval from beer by reverse osmosis. AIChE Symposium Series,82, 1–8.

Magalhães, P. J., Dostalek, P., Cruz, J. M., Guido, L. F., & Barros, A. A.(2008). The impact of a xanthohumol-enriched hop product on thebehavior of xanthohumol and isoxanthohumol in pale and darkbeers: a pilot scale approach. Journal Institute of Brewing, 114(3),246–256.

Matsumoto, K., Katsuyama, S. S., &Ohya, H. (1987). Separation of yeastby cross-flow filtration with backwashing. Journal of FermentationTechnology, 65(1), 77–83.

Mellcom. (2012). Carbon dioxide recovery plant. New Delhi—India:Mellcon Engineers Pvt Ltd. Retrieved from http://www.mellcon.com/co2-recovery-plant.asp

Montanari, L., Marconi, O., Mayer, H., & Fantozzi, P. (2009). Productionof alcohol-free beer. In V. R. Preedy (Ed.), Beer in health anddisease prevention (pp. 61–75). Burlington: Elsevier Inc.

Moonen, H., & Niefind, H. J. (1982). Alcohol reduction in beer bymeansof dialysis. Desalination, 41(3), 327–335.

Murkes, J. (1986). Low shear and high shear crossflow filtration.Filtration and Separation, 23(6), 364–366.

Mussatto, S. I., Dragone, G., & Roberto, I. C. (2006). Brewers’ spentgrain: generation, characteristics and potential applications. Journalof Cereal Science, 43(1), 1–14.

O’Reilly, S. M. G., Lummis, D. J., & Molzahn, S. W. (1987). Theapplication of ceramic filtration for the recovery of beer from tankbottoms and in beer filtration. In Proceedings of European BrewingConvention (pp. 639–646). Madrid - Spain.


http://dx.doi.org/10.1002/jib.18

http://www.westfalia-separator.com/fileadmin/Media/PDFs/Digest/SeparatorsDigest-2009-3-EN-100-Years-beer-separation.pdf



http://www.geabrewery.com/geabrewery/cmsresources.nsf/filenames/Refrigeration_E_0712.pdf/-2ile/Refrigeration_E_0712.pdf



http://www.westfalia-separator.com/fileadmin/Media/PDFs/Brochures/Breweries-BE-12-10-0004.pdf



http://www.mellcon.com/co2-recovery-plant.asp

http://www.mellcon.com/co2-recovery-plant.asp

Ohlrogge, K., Wind, J., & Brinkmann, T. (2010). Membranes for recov-ery of volatile organic compounds. In Comprehensive MembraneScience and Engineering (pp. 213–242). Oxford: Elsevier.

Pall. (2013). Keraflux - TFF System. Pall Corporation. Retrieved fromhttp://www.pall.com/main/food-and-beverage/product.page?id=53876.

Pentair. (2012). Beverages systems. Pentair Water Process TechnologyBV. Retrieved from http://pentair.com/MarketLanding/resources/images/7662.pdf.

Pentair. (2013). Beer membrane filtration. Pentair Water ProcessTechnology BV2. Retrieved from http://www.norit-bmf.com/facts& figures/.

Perry, E. J., & Coleman, A. R. (1987). Purification of carbon dioxide foruse in brewing. US patent No 4699642.

Petkovska, M., Leskosek, I., & Nedovic, V. (1997a). Analysis of masstransfer in beer diafiltration with cellulose-based and polysulfonemembranes. Institute of Chemical Engineers, 75(4), 247–252.

Petkovska, M., Leskosek, I., & Nedovic, V. (1997b). Analysis of masstransfer in beer diafiltration with cellulose-based and polysulfonemembranes. Food and Bioproducts Processing, 75(4), 247–252.

Pilipovik, M. V., & Riverol, C. (2005). Assessing dealcoholization sys-tems based on reverse osmosis. Journal of Food Engineering, 69(4),437–441.

Priest, F. G., & Stewart, G. G. (Eds.). (2006). Handbook of brewing (2ndEdition, p. 830). Boca Raton: CRC Press Inc.

Rufford, T. E., Smart, S.,Watson, G. C. Y., Graham, B. F., Boxall, J., Dinizda Costa, J. C., et al. (2012). The removal of CO2 and N2 from naturalgas: a review of conventional and emerging process technologies.Journal of Petroleum Science and Engineering, 94–95, 123–154.

Sandblom, R. M. (1978). Filtering process. US patent No 4105547.Schneider, J., & Weisser, H. (2004). Diafiltration of mash. Journal of the

Institute of Brewing, 110(4), 326–334.Schneider, J., Krottenthaler, M., Back, W., & Weisser, H. (2005). Study

on the membrane filtration of mash with particular respect to thequality of wort and beer. Journal of the Institute of Brewing, 111,380–387.

Sensidoni, M., Marconi, O., Perretti, G., Freeman, G., & Fantozzi, P.(2011). Monitoring of beer filtration using photon correlation spec-troscopy (PCS). Journal of the Institute of Brewing, 117(4), 639–646.

Shotipruk, A., Kittianong, P., Suphantharika, M., & Muangnapoh, C.(2005). Application of rotary microfiltration in debittering processof spent brewer’s yeast. Bioresource Technology, 96(17), 1851–1859.

Sohrabvandi, S., Mousavi, S. M., Razavi, S. H., Mortazavian, A. M., &Rezaei, K. (2010). Alcohol-free beer: methods of production, sen-sorial defects, and healthful effects. Food Reviews International,26(4), 335–352.

Starbard, N. (2008). Beverage industry microfiltration: a comprehensiveguide (p. 303). Iowa: Wiley-Blackwell.

Stein, W. (1993). Dealcoholization of beer. Technical Quarterly—MasterBrewers Association of the Americas, 30(2), 54–57.

Stewart, D. C., Hawthorne, D., & Evans, D. E. (1998). Coldsterile filtration: a small scale filtration test and investigationof membrane plugging. Journal of the Institute of Brewing,104, 321–326.

Stopka, J., Schlosser, S., Dömény, Z., & Smogrovicova, D. (2000). Fluxdecline in microfiltration of beer and related solutions of modelfoulants through ceramic membranes. Polish Journal ofEnvironmental Studies, 9(1), 65–69.

Tan, S., Li, L., Xiao, Z., Wu, Y., & Zhang, Z. (2005). Pervaporation ofalcoholic beverages—the coupling effects between ethanol andaroma compounds. Journal of Membrane Science, 264(1–2), 129–136.

Tang, D.-S., Yin, G.-M., He, Y.-Z., Hu, S.-Q., Li, B., Li, L.,…Borthakur,D. (2009). Recovery of protein from brewer’s spent grain by ultra-filtration. Biochemical Engineering Journal, 48(1), 1–5.

Tilgner, H. G., & Schmitz, F. J. (1987). Process for reducing alcohol infermented beverages by means of dialysis. US patent No 4664918.

Tripp, M. L., Rader, S. R., Rao, S. C., & Ryder, D. S. (1997). Flavoredmalt beverages prepared by using ultrafiltration methods. US patentNo 5618572.

Vadi, P., & Rizvi, S. S. (2001). Experimental evaluation of a uniformtransmembrane pressure crossflow microfiltration unit for the con-centration of micellar casein from skim milk. Journal of MembraneScience, 189(1), 69–82.

Van der Sman, R. G. M., Vollebregt, H. M., Mepschen, A., & Noordman,T. R. (2012). Review of hypotheses for fouling during beer clarifi-cation using membranes. Journal of Membrane Science, 396, 22–31.

Van Rijn, C. J. M., Nijdam, W., van der Stappen, L. A. V. G., Raspe, O. J.A., Broens, l., & van Hoof, S. C. J. M. (1997). Innovation in yeastcell filtration: cost saving technology with high flux membranes. InProceedings of the EBC Congress (pp. 501–507).

Wenten, I. G., Taylour, J., Skou, F., Rasmussen, A., & Jonsson, G. (1994).Membrane cleaning after beer clarification. In Proceedings ofEuropean Brewing Convention (pp. 188–195). Sydney—Australia:University of New South Wales.

Wittemann. (2012). Carbon dioxide recovery (Brewery). Palm Coast—USA: Wittemann Company. Retrieved from http://www.pureco2nfidence.com/launch/images/downloads/literature/brewery/brewery_recovery_literature.pdf.

Yang, H., Xu, Z., Fan, M., Gupta, R., Slimane, R. B., Bland, A. E., et al.(2008). Progress in carbon dioxide separation and capture: a review.Journal of Environmental Sciences, 20(1), 14–27.

Yazdanshenas,M., Soltanieh, M., Tabatabaei, N., Reza, S. A., Fillaudeau,L., & Tabatabaei Nejad, S. A. R. (2010). Cross-flow microfiltrationof rough non-alcoholic beer and diluted malt extract with tubularceramic membranes: investigation of fouling mechanisms. Journalof Membrane Science, 362(1–2), 306–316.

Yeo, Z. Y., Chew, T. L., Zhu, P. W., Mohamed, A. R., & Chai, S.-P.(2012). Conventional processes and membrane technology for car-bon dioxide removal from natural gas: a review. Journal of NaturalGas Chemistry, 21(3), 282–298.


http://www.pall.com/main/food-and-beverage/product.page?id=53876

http://www.pall.com/main/food-and-beverage/product.page?id=53876

http://pentair.com/MarketLanding/resources/images/7662.pdf

http://pentair.com/MarketLanding/resources/images/7662.pdf

http://www.norit-bmf.com/facts

http://www.pureco2nfidence.com/launch/images/downloads/literature/brewery/brewery_recovery_literature.pdf



Membrane Separation Processes for the Beer Industry: a Review and State of the Art

Documents

Transcript of Membrane Separation Processes for the Beer Industry: a Review and State of the Art