Removal of Alcohol from Beer Using Membrane Processes
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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 Rethinking the process for alcohol free beer (AFB) production focusing on aroma and flavour 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. Although beer is perceived by the public as unhealthy, due to the alcohol content, 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 CO2 pressure of 1-2bar. The alcohol concentration during filtration was 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. Future consideration involving alteration of the brewing and fermentation processes were 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 Bethanol Solute transport coefficient NFHF Nano filtration membrane type Bwater Solvent transport coefficient NF99HF 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 DAM Solutes diffusion coefficient PP Polypropylene 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 tR Retention time 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.10 HPLC Report . 127 A.11 HS Sampling Set-up . 128 A.12 HS-GC-MS Spectra . 129 A.13 Alfa Laval Membrane Classification . 130 A.14 Standard 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.