- Email: [email protected]
Beer dealcoholization by reverse osmosis
Desalination 200 (2006) 397–399
Beer dealcoholization by reverse osmosis Margarida Catarinoa, Adélio Mendesa*, Luis Madeiraa, António Ferreirab a
LEPAE, Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Roberto Frias, 4200-465 Porto, Portugal Tel. +351-22-5081695; Fax +351-22-5081449; email: [email protected] b Unicer, Beverages of Portugal S.A., Via Norte, Leça do Balio, 4465-955 S. Mamede de Infesta, Portugal Received 18 October 2005; accepted 2 March 2006
1. Introduction Nowadays it is observed a significant increase in the consumption of non-alcoholic beverages, which is mainly due to medical or health reasons. In addition, people are becoming aware of problems that alcohol can bring regarding civil responsibilities. There is a suitable range of processes for producing non-alcoholic or low alcohol beer. These processes can be divided in processes of restricted alcohol formation and in alcohol removal processes. The last ones include heatand membrane-based processes (which comprise vacuum distillation, water vapour stripping under vacuum, dialysis and reverse osmosis) [1]. In this project the reverse osmosis technology is used for producing non-alcoholic beer (alcohol concentration < 0.5 vol.%) from a fermented beer with 5.5% alcohol. Evaluations of the sensorial quality of the produced beer recognized a promising taste on the final product. 2. Experimental In the reverse osmosis process, the product to be treated flows tangentially to the membrane *Corresponding author.
surface and a portion of the feed flowrate (permeate) crosses selectively the membrane, while the other fraction (retentate) remains in the feed side. This phenomenon can be observed if a pressure that overcomes the osmotic pressure is applied in the feed side of the membrane, which has higher solute concentration, in order to make the solvent (e.g. water) to permeate through the membrane [2]. This principle can be applied to remove alcohol from beer if a membrane semi-permeable to the alcohol is used. This way, alcohol (and water) permeates the membrane against the natural osmotic pressure and are recovered in the permeate side. On the other hand, the larger molecules, such as beer aroma and flavour compounds, mostly remain in the concentrated beer (retentate). Normally the reverse osmosis is applied to the beer in a batch or semi-batch way, where the retentate is recycled to the feed. The retentate loses important amounts of water in this process, besides alcohol, which should be added continuously to the feed or, at the end, to the retentate volume produced. The added water should be deaerated and deionised. In this project it is used a reverse osmosis laboratory unit that operates batch-wise for removing alcohol from beer. The beer is pumped
Presented at EUROMEMBRANE 2006, 24–28 September 2006, Giardini Naxos, Italy. 0011-9164/06/$– See front matter © 2006 Published by Elsevier B.V. doi:10.1016/j.desal.2006.03.346
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M. Catarino et al. / Desalination 200 (2006) 397–399
Table 1 Experimental results for the reverse osmosis process using cellulose acetate membranes (200 MWCO, provided by Alfa Laval) Exp #
T (°C)
Pf (atm)
C0 (%v/v)
Qf (l/min)
Qp (mL/s)
Cp (% v/v)
R (%)
a b c d e f g
10 10 20 7 5 4 6
40 40 40 40 40 40 20
5.45 5.43 5.47 5.48 5.49 5.50 5.40
1.96 2.84 7.22 7.22 7.22 7.22 7.22
0.090 0.090 0.120 0.080 0.061 0.056 0.039
3.84 3.63 2.29 2.04 2.03 2.01 2.16
29.5 33.2 58.1 62.8 63.0 63.5 60.0
T — temperature, Pf — feed pressure, C0 — initial feed concentration of alcohol, Qf — feed flowrate, Qp — permeate flowrate, Cp — 180 min permeate concentration of alcohol, R – alcohol rejection.
through the membrane module with 155-cm2 effective membrane area. The retentate is recycled to the feed reservoir through a heat exchanger, which is used for keeping the temperature constant. The feed pressure and retentate flowrate are measured using a manometer and a rotameter, respectively, which are adjusted using needle valves. The temperature is also measured in the feed tank and in the membrane module. The membrane module temperature is controlled adjusting the cooling water flowrate in the heat exchanger. 3. Results and discussion Several preliminary experiments have been performed to evaluate the effect of the most critical operation conditions in the membrane process, having in mind the production of a non-alcoholic beer (alcohol concentration < 0.5 vol.%) with a sensorial quality similar to the original one. The main results are summarized in Table 1. From the results shown in Table 1 it can be seen that both ethanol permeate flux and rejection increase with the feed pressure (runs d and e and g). The permeate flowrate increases with the temperature while the rejection decreases
with it (runs c, d, e and f ). The concentration polarization should be negligible at the high flowrates considered in experiments c–g. Several membranes were tested for performing the beer dealcoholization. The membranes considered are made of cellulose acetate (Ref: DSS-CA995P, Molecular Weight Cut-Off of 200, supplied by Alfa Laval), polyamide (Ref: BW RLC, BW 30 LE and SW 30 HR, all supplied by Centec) and fiberglass-supported polyamide (Ref: ACM 4 and ACM 2, both supplied by Centec). The membrane from Alfa Laval was selected because it showed the highest permeate flux and the smaller ethanol rejection. 4. Conclusions From the preliminary results it can be concluded that reverse osmosis is an effective process to produce non-alcoholic beer, with ethanol values below 0.5% by volume. The most critical parameters in the membrane process have been studied and it can be concluded that the most promising conditions for alcohol removal are the maximum pressures that membranes can support (due to the higher permeate flux and better aroma profile, although increasing slightly the ethanol rejection) and the optimal
M. Catarino et al. / Desalination 200 (2006) 397–399
temperature is around 5°C. At low temperatures membranes become more effective (higher rejection to aroma compounds) and heat sensitive compounds of the beer do not suffer any changes. Nevertheless, it is crucial to control the operation conditions that can make a great difference in the final product quality. This means that it is necessary to perform more tests in order to evaluate the effect of the process variables and the operation mode of the
399
dealcoholization on the beer quality in order to produce a non-alcoholic beer with an aroma profile similar to the original one. References [1] [2]
W. Kunze, Technology Brewing and Malting, VLB, Berlin, Germany, 1999. M. Mulder, Basic Principles of Membrane Technology, Kluwer Academic Publishers, Enschede, Netherlands, 2000.
Beer dealcoholization by reverse osmosis Margarida Catarinoa, Adélio Mendesa*, Luis Madeiraa, António Ferreirab a
LEPAE, Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Roberto Frias, 4200-465 Porto, Portugal Tel. +351-22-5081695; Fax +351-22-5081449; email: [email protected] b Unicer, Beverages of Portugal S.A., Via Norte, Leça do Balio, 4465-955 S. Mamede de Infesta, Portugal Received 18 October 2005; accepted 2 March 2006
1. Introduction Nowadays it is observed a significant increase in the consumption of non-alcoholic beverages, which is mainly due to medical or health reasons. In addition, people are becoming aware of problems that alcohol can bring regarding civil responsibilities. There is a suitable range of processes for producing non-alcoholic or low alcohol beer. These processes can be divided in processes of restricted alcohol formation and in alcohol removal processes. The last ones include heatand membrane-based processes (which comprise vacuum distillation, water vapour stripping under vacuum, dialysis and reverse osmosis) [1]. In this project the reverse osmosis technology is used for producing non-alcoholic beer (alcohol concentration < 0.5 vol.%) from a fermented beer with 5.5% alcohol. Evaluations of the sensorial quality of the produced beer recognized a promising taste on the final product. 2. Experimental In the reverse osmosis process, the product to be treated flows tangentially to the membrane *Corresponding author.
surface and a portion of the feed flowrate (permeate) crosses selectively the membrane, while the other fraction (retentate) remains in the feed side. This phenomenon can be observed if a pressure that overcomes the osmotic pressure is applied in the feed side of the membrane, which has higher solute concentration, in order to make the solvent (e.g. water) to permeate through the membrane [2]. This principle can be applied to remove alcohol from beer if a membrane semi-permeable to the alcohol is used. This way, alcohol (and water) permeates the membrane against the natural osmotic pressure and are recovered in the permeate side. On the other hand, the larger molecules, such as beer aroma and flavour compounds, mostly remain in the concentrated beer (retentate). Normally the reverse osmosis is applied to the beer in a batch or semi-batch way, where the retentate is recycled to the feed. The retentate loses important amounts of water in this process, besides alcohol, which should be added continuously to the feed or, at the end, to the retentate volume produced. The added water should be deaerated and deionised. In this project it is used a reverse osmosis laboratory unit that operates batch-wise for removing alcohol from beer. The beer is pumped
Presented at EUROMEMBRANE 2006, 24–28 September 2006, Giardini Naxos, Italy. 0011-9164/06/$– See front matter © 2006 Published by Elsevier B.V. doi:10.1016/j.desal.2006.03.346
398
M. Catarino et al. / Desalination 200 (2006) 397–399
Table 1 Experimental results for the reverse osmosis process using cellulose acetate membranes (200 MWCO, provided by Alfa Laval) Exp #
T (°C)
Pf (atm)
C0 (%v/v)
Qf (l/min)
Qp (mL/s)
Cp (% v/v)
R (%)
a b c d e f g
10 10 20 7 5 4 6
40 40 40 40 40 40 20
5.45 5.43 5.47 5.48 5.49 5.50 5.40
1.96 2.84 7.22 7.22 7.22 7.22 7.22
0.090 0.090 0.120 0.080 0.061 0.056 0.039
3.84 3.63 2.29 2.04 2.03 2.01 2.16
29.5 33.2 58.1 62.8 63.0 63.5 60.0
T — temperature, Pf — feed pressure, C0 — initial feed concentration of alcohol, Qf — feed flowrate, Qp — permeate flowrate, Cp — 180 min permeate concentration of alcohol, R – alcohol rejection.
through the membrane module with 155-cm2 effective membrane area. The retentate is recycled to the feed reservoir through a heat exchanger, which is used for keeping the temperature constant. The feed pressure and retentate flowrate are measured using a manometer and a rotameter, respectively, which are adjusted using needle valves. The temperature is also measured in the feed tank and in the membrane module. The membrane module temperature is controlled adjusting the cooling water flowrate in the heat exchanger. 3. Results and discussion Several preliminary experiments have been performed to evaluate the effect of the most critical operation conditions in the membrane process, having in mind the production of a non-alcoholic beer (alcohol concentration < 0.5 vol.%) with a sensorial quality similar to the original one. The main results are summarized in Table 1. From the results shown in Table 1 it can be seen that both ethanol permeate flux and rejection increase with the feed pressure (runs d and e and g). The permeate flowrate increases with the temperature while the rejection decreases
with it (runs c, d, e and f ). The concentration polarization should be negligible at the high flowrates considered in experiments c–g. Several membranes were tested for performing the beer dealcoholization. The membranes considered are made of cellulose acetate (Ref: DSS-CA995P, Molecular Weight Cut-Off of 200, supplied by Alfa Laval), polyamide (Ref: BW RLC, BW 30 LE and SW 30 HR, all supplied by Centec) and fiberglass-supported polyamide (Ref: ACM 4 and ACM 2, both supplied by Centec). The membrane from Alfa Laval was selected because it showed the highest permeate flux and the smaller ethanol rejection. 4. Conclusions From the preliminary results it can be concluded that reverse osmosis is an effective process to produce non-alcoholic beer, with ethanol values below 0.5% by volume. The most critical parameters in the membrane process have been studied and it can be concluded that the most promising conditions for alcohol removal are the maximum pressures that membranes can support (due to the higher permeate flux and better aroma profile, although increasing slightly the ethanol rejection) and the optimal
M. Catarino et al. / Desalination 200 (2006) 397–399
temperature is around 5°C. At low temperatures membranes become more effective (higher rejection to aroma compounds) and heat sensitive compounds of the beer do not suffer any changes. Nevertheless, it is crucial to control the operation conditions that can make a great difference in the final product quality. This means that it is necessary to perform more tests in order to evaluate the effect of the process variables and the operation mode of the
399
dealcoholization on the beer quality in order to produce a non-alcoholic beer with an aroma profile similar to the original one. References [1] [2]
W. Kunze, Technology Brewing and Malting, VLB, Berlin, Germany, 1999. M. Mulder, Basic Principles of Membrane Technology, Kluwer Academic Publishers, Enschede, Netherlands, 2000.