Removal of Alcohol From Beer Using Membrane Processes

132 Pages·2014·8.17 MB·English

Removal of Alcohol From Beer Using
Membrane Processes
Master’s Thesis
Supervisors:
Author:
Henrik Siegumfeldt
Andreas Jakob Wedel Falkenberg
Jens Christian Sørensen
In collaboration with:
July 31, 2014
Title page
Title:
Removal of Alcohol From Beer Using Membrane Processes
Author:
Andreas Jakob Wedel Falkenberg (zdg243)
Duration:
6 months
4/2 - 4/8-2014
30 ECTS
Supervisors:
Henrik Siegumfeldt
Jens Christian Sørensen
Copies:
Printed in 3 copies, as well as being digitally available
Thesis:
Master’s Thesis in Brewing Science and Technology
Number of pages: 94
Written in LATEX
Written at:
Department of Food Science
University of Copenhagen Faculty of Science
In collaboration with:
Brewhouse Skands A/S and Alfa Laval Nakskov A/S
1
Preface and Acknowledgement
Rethinkingtheprocessforalcoholfreebeer(AFB)productionfocusingonaromaandflavour
quality was the original idea of this thesis. An investigation was initiated revealing possible
new methods of AFB production. This focusing not only on the process technologies re-
lated to alcohol removal from normal alcoholic beer, but in addition looking beyond at the
general beer production processes to indicate possible changes resulting in a higher quality
AFB with regards to aroma and flavour preservation.
I would like to thank all parties involved from the University of Copenhagen Faculty
of Science, Brewhouse Skands A/S and Alfa Laval A/S. From the University of Copen-
hagen Faculty of Science a special thanks to my supervisors Associate Professor Henrik
Siegumfeldt and Associate Professor Jens Christian Sørensen for knowledgeable guidance,
participation and support. Furthermore, thanks to my fellow student Tobias Emil Jensen
and his supervisor Mikael Agerlin Petersen for guidance and permission to run head space
gas chromatographic mass spectrometry samples. From Brewhouse Skands A/S a special
thanks to Birthe and Morten Skands for guidance, participation and beer donations. From
Alfa Laval a special thanks to Anders Bisgaard for guidance, participation, membrane do-
nations and introduction to the newest trends in membrane processing.
Furthermore, I would like to thank M.Sc. in Chemical Engineering Jascha Rosenbaum
and M.Sc. in Physical Engineering Christoffer Klærke for support and proof reading of the
thesis. Thanks to Diploma Master Brewer Anders Nielsen for participation in beer tasting
and proof reading. Finally, I would like to thank my family and friends for being supportive
in the process of producing this thesis.
2
Abstract
The main object of this study is the production of alcohol free beer (AFB) using membrane
processes. Althoughbeerisperceivedbythepublicasunhealthy, duetothealcoholcontent,
it actually contains numerous nutrients.
Traditionally AFB is produced using either thermal processes such as evaporation and
rectification or modified brewing and fermentation. These approaches induce pronounced
and unwanted changes to the overall flavour profile of beer. Membrane processes for the
production of AFB are poorly investigated, however the potential is large because of pos-
sible non-thermal selective ethanol removal. A major drawback in membrane processes is
the difficulty in removing ethanol below 0.5% alcohol by volume (ABV) without high ex-
penses. In Denmark the legal limit for AFB labelling was recently changed from 0.1%ABV
to 0.5%ABV making membrane processes a viable alternative for future AFB production.
This study compares the potential of four different membranes ranging in pore size from
nano filtration (NF) to reverse osmosis (RO). The membranes were tested on a Labstak
M20-0.72 membrane unit provided by Alfa Laval A/S using Humlefryd 5.5%ABV lager pro-
vided by Brewhouse Skands A/S. The M20-0.72 unit was modified to maintain a closed
environment with a CO pressure of 1-2bar. The alcohol concentration during filtration was
2
determined using high performance liquid chromatography (HPLC), where the flavour pro-
files before and after filtration were compared using head space gas chromatography mass
spectrometry (HS-GC-MS). Additionally, a trained taste panel was used to describe the
differences in the membrane filtrated products compared to the original beer.
Investigations showed that RO membrane filtration provided a good aroma retention
while the ethanol permeability and flux through the membrane were low. On the other
hand, the different NF membranes had a higher ethanol permeability while a higher loss of
aroma was observed.
As a result, production of AFB using RO membranes will induce a higher capital expen-
diture (CAPEX) for membranes and tanks plus a higher operational expenditure (OPEX)
for pump work, cooling and water consumption, however the product will have a higher
aroma quality. On the contrary, NF membranes will lower both the CAPEX and the OPEX
as well as the quality.
Futureconsiderationinvolvingalterationofthebrewingandfermentationprocesseswere
considered hereby compensating for the aroma losses over RO and NF membranes making
this process more profitable.
3
Abbreviations
σ∗ Polar Taft number MCFA Medium chain fatty acid
δ Membrane thickness MF Micro filtration
AA Amino acids MS Mass spectrometry
ABV Alcohol by volume MWCO Molecular weight cut-off
ADP Adenosine diphosphate NAD+ Nicotinamide adenine
AFB Alcohol free beer dinucleotide
ATP Adenosine triphosphate NF Nano filtration
B Solute transport coefficient NFHF Nano filtration membrane type
ethanol
B Solvent transport coefficient NF99HF
water
C∗ Membrane constant OPEX Operational expenditure
CA Cellulose acetate ORG Original
CAPEX Capital expenditure P Permeate and permeability
CCV Cylindroconical vessels PA Polyamide
CI Chemical ionization PC Principal component
CIP Cleaning in place PCA Principal component analysis
CoA-SH Coenzyme A PE Polyester
Conc. Concentration PES Polyethersulfone
CTA Cellulose triacetate PG Present gravity
DAB Danish Brewers’ Association PM Permeability
D Solutes diffusion coefficient PP Polypropylene
AM
DC Direct current PS Polysulfone
DF Diafiltration PT Permeate tank
E2N (E)-2-Nonenal PVDF Polyvinyllidene fluoride
EI Electron ionization Re Retention
Es∗ Steric Taft number RF Radio frequency
F Flow RI Refractive index
FAD+ Flavin adenine dinucleotide RID Refractive index detector
FAN Free amino nitrogen RO Reverse osmosis
FT Feed tank s∗ Small’s number
FTE Feed tank end SD Standard deviation
GC Gas chromatography SDME Single drop micro extraction
GTP Guanosine triphosphate SPME Solid phase micro extraction
HA Higher alcohols TA Trapping agent
HF Humlefryd and high flux TCA Tricarboxylic acid cycle
HGB High gravity brewing TFC Thin film composition
HP High performance/pressure TMC Trimethyl chloride
HS Head space TMP Trans membrane pressure
J Flux t Retention time
R
K Distribution ratio between UF Ultra filtration
membrane and solution VCF Volume concentration factor
KU University of Copenhagen VDK Total vicinal diketones
LAB Low alcoholic beer VOC Volatile organic compounds
LC Liquid chromatography WCOT Wall coated open tubes
4
Contents
1 Introduction 7
2 Theory 11
2.1 Sedimentation and Filtration . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2 Membrane Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3 Experimental Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.4 Aroma Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.5 Methods of Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
3 Materials and Methods 53
3.1 Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
3.2 Membranes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.3 Feed Beer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.4 Dia-water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.5 Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.6 Analytical Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4 Results and Discussion 62
4.1 Preliminary Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.2 Constant Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4.3 Membrane Flux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.4 Ethanol Permeability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
4.5 Aroma Retention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
4.6 Tasting Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
4.7 Overall Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
4.8 Aroma Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
5 Future Perspectives 92
6 Conclusion 94
A Appendices 106
A.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
A.2 Diafiltration Approximation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
A.3 E2N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
A.4 Ketones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
A.5 Sulphur Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
A.6 Acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
5
CONTENTS CONTENTS
A.7 Hops Acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
A.8 HS-GC-MS Feed Beer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
A.9 HPLC Calibration Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
A.10HPLC Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
A.11HS Sampling Set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
A.12HS-GC-MS Spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
A.13Alfa Laval Membrane Classification . . . . . . . . . . . . . . . . . . . . . . . . 130
A.14Standard Deviation of HS-GC-MS Samples . . . . . . . . . . . . . . . . . . . 131
6
Chapter 1
Introduction
The evolution of alcoholic beverages have changed the course of history ranging from scien-
tific breakthroughs to prohibition and legislations. With a higher scientific enlightenment
alcoholic beverages have been deemed unhealthy by some, while healthy by others. Fur-
thermore, the intoxicating effect of alcoholic beverages has caused the need for legislations
concerning the intake of alcohol. Alcoholic beverages never seem to go out of fashion, how-
ever the public view, legislations and assortments seem to change drastically over the course
of time (Gretton, 1929).
Beer has gone from being a home made product, enabling personal preferences, to be-
coming an industrialized production, where supply and demand are in focus. An expand
in assortment of beers is caused by a higher competition and a globalization resulting in
many different beer styles. In addition, technological development have caused a higher
differentiation in beer enabling alcohol removal or reduction. Low alcohol beer (LAB) and
alcohol free beer (AFB) are present on the market for the purpose of satisfying customer
demands. This demand could be caused by legislation, health issues, religion, prohibition
or as an alternative to soft drinks (Ambrosi et al., 2014).
For many years health have been the main concern or argument when legislating and
banning beer consumption. A high consumption of beer can lead to alcoholism, accidents,
brain degeneration, liver failure, cancer, strokes and arteriosclerosis. Many of these illnesses
are associated to the alcohol intake when drinking beer. Nevertheless, some positive affects
of beer drinking have been observed when drinking moderately or drinking LAB or AFB.
Drinking one to six regular alcoholic beers a week have shown to have positive attributes
described by the so-called J-curve as shown in figure 1.1. The figure illustrates a reduc-
tion in mortality for people drinking moderately compared to people not drinking. The
reduction in mortality associated with moderate alcohol intake is mainly caused by alcohol
lowering the risk of coronary diseases. For many years physicians have recommended wine
for patients in danger of coronary diseases, when beer is equally sufficient. In fact, beer
contributes with constituents with additional positive health effect. This could be an addi-
tional reasoning for choosing an AFB or LAB instead of soft drinks where the nutrients and
vitamins concentration are low to non-excising (Furbo, 2013), (Groenbaek et al., 1994).
Legislation in most European countries concerning alcohol concentration in beer states
that beer with an alcohol concentration below 0.5%ABV are allowed to be labelled AFB,
whilebeerbelow1.2%ABVareallowedtobelabelledLAB.Inrelationtoreligion, especially
intheMuslimworld,theallowedconcentrationismostoftenbelow0.05%ABV,onlyallowing
traces of alcohol in beverages (Br´anyik et al., 2012).
In Denmark the legislation concerning AFB labelling was recently changed allowing
7
CHAPTER 1. INTRODUCTION
Figure 1.1: Relative risk of mortality compared to the weekly alcohol intake. Vertical lines
indicate the 95% confidence interval (Groenbaek et al., 1994).
0.5%ABV instead of the previously allowed 0.1%ABV. This change was induced by the
Danish Brewers’ Association (DBA) highlighting concerns about the low quality of Danish
AFB. According to DBA the low quality and low sales of AFB in Denmark could be altered
to the better by allowing a higher concentration of AFB at 0.5%ABV, as observed in other
countriessuchasGermany, SwedenandSpain. InthesecountriesAFBaccountsforahigher
percentage of the market shares hereby increasing the accessibility of these product (Quass,
2013), (Gormsen, 2013).
As stated above, legislation, health and religion are some of the factors creating the
demand for LAB and AFB. The current technology of reducing alcohol can be divided into
two subsequent methods of respectively physical and biological methods. In figure 1.2 an
overview and summary of these two methods of producing AFB and LAB can be observed.
The physical methods entail gentle removal of already created alcohol in the beer by separa-
tion using heat and pressure alteration or mechanical separation using membranes. On the
other hand, the biological methods entail the use of special yeast, mashing or fermentation
methodsinthetraditionalbrewingequipmentorinnewequipment,enablingashortcontact
time with the wort and yeast. The physical methods often result in a great loss of volatiles
which leaves the beer flavourless and watery. On the contrary, the biological methods often
leave the beer, worthy and unbalanced. In a review by Br´anyik et al. (2012) a comparison
of physical processes reveal a lower loss of volatiles using membrane processes compared to
thermal processes. Furthermore, thermal processes cause irreversible heat damages to the
beerresultinginahigherrateofdeteriorationandunpleasantbitternessformation(Br´anyik
et al., 2012).
Membrane processes might cause a high reduction in volatiles because some of the taste
and aroma substances are able to pass through the membrane along with alcohol. This
could result in a loss of mouth feel, taste, body and aroma, see appendix A.1 for glossary.
Nevertheless, the irreversible alteration of flavour and aroma compounds is considerably
reduced, because this process is performed cold.
Membrane processes are investigated in this thesis for the purpose of characterising pos-
8
CHAPTER 1. INTRODUCTION
sible losses of volatiles during the process. The differences in ethanol and aroma permeation
through various membranes ranging from nano filtration (NF) to reverse osmosis (RO) are
classifiedusingHPLCandHS-GC-MS.Finally,possiblewaysofalteringthebrewingprocess
tocompensateforthelossesofflavourandaromacompoundsduringthemembranefiltration
will be discussed. Hopefully, membrane processes will enable a more flavourful AFB and
LAB if the losses over the membrane are standardised and hereby correctly compensated
for during the many steps of brewing and fermentation (Br´anyik et al., 2012).
Throughout this thesis different technological brewing and process terms might be used,
which are not defined directly in the text. For the purpose of simplification and readability
possible term or word explanations are assembled in appendix A.1.
9