Experimental Study and Modeling of Beer Dealcoholization via Reverse Osmosis

The goals of the present investigation are to study and to model pale lager beer dealcoholization via reverse osmosis (RO). Samples were dealcoholized at a temperature of 15 ± 1 °C. An Alfa Laval RO99 membrane with a 0.05 m² surface was used. The flux values were measured during the separations. The ethanol content, extract content, bitterness, color, pH, turbidity, and dynamic viscosity of beer and permeate samples were measured. The initial flux values were determined using linear regression. The initial ethanol flux (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>J</mi><mrow><mi>E</mi><mi>t</mi><mi>O</mi><mi>H</mi><mo> </mo><mn>0</mn></mrow></msub></mrow></semantics></math></inline-formula>) values were calculated from the initial flux values and the ethanol content values. A 2^P full factorial experimental design was applied, and the factors were as follows: transmembrane pressure (TMP): 10, 20, 30 bar; retentate flow rate (Q): 120, 180, 240 L/h; <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>J</mi><mrow><mi>E</mi><mi>t</mi><mi>O</mi><mi>H</mi><mo> </mo><mn>0</mn></mrow></msub></mrow></semantics></math></inline-formula> was considered as the response. The effect sizes of the significant parameters were calculated. The global maximum of the objective function was found using a self-developed Grid Search code. The changes in the analytical parameters were appropriate. The TMP had a significant effect, while the Q had no significant effect on the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>J</mi><mrow><mi>E</mi><mi>t</mi><mi>O</mi><mi>H</mi><mo> </mo><mn>0</mn></mrow></msub></mrow></semantics></math></inline-formula>. The effect size of the TMP was 1.20. The optimal value of the factor amounted to TMP = 30 bar. The predicted <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>J</mi><mrow><mi>E</mi><mi>t</mi><mi>O</mi><mi>H</mi><mo> </mo><mn>0</mn></mrow></msub></mrow></semantics></math></inline-formula> under the above conditions was 121.965 g/m² h.