Kvasny Prum. 2003; 49(5): 114-119 | DOI: 10.18832/kp2003006

Aerobic and Anaerobic Beer Ageing.Peer-reviewed article

Jan ŠAVEL

Budějovický Budvar, n.p., Karoliny Světlé 4, 370 21 České Budějovice

Model experiments of phenylalanine oxidation in the solution of ascorbic acid proved that the oxygen and activator (Cu2+) are necessary for effective oxidation. This mechanism can explain the formation of volative aldehydes from amino acids during the aerobic ageing of beer. When there is a lack of oxygen the aldehydes form only in small amounts. Participation of oxygen in presence of activators during the aging of beer has been confirmed also by the reoxidation of methylene blue leucoform, prepared by methylene blue reduction with ascorbic acid after exposing to visible light. Based on the same principle there has been proved the presence of different activators of reoxidation in beer, hopped wort, apple juice plus active presence of nitrite sodium or methylene red during the aerobic reoxidation of methyl blue leucoform. On the contrary atmospheric oxygen inhibited methyl red degradation in the solution of ascorbic acid, which is an example of colouring agents degradation under the anaerobic conditions. The examples of positive and negative action of reducing agents during the production of beer and significant role of beer colouring agents during its ageing is being stated here.Model experiments of phenylalanine oxidation in the solution of ascorbic acid proved that the oxygen and activator (Cu2+) are necessary for effective oxidation. This mechanism can explain the formation of volative aldehydes from amino acids during the aerobic ageing of beer. When there is a lack of oxygen the aldehydes form only in small amounts. Participation of oxygen in presence of activators during the aging of beer has been confirmed also by the reoxidation of methylene blue leucoform, prepared by methylene blue reduction with ascorbic acid after exposing to visible light. Based on the same principle there has been proved the presence of different activators of reoxidation in beer, hopped wort, apple juice plus active presence of nitrite sodium or methylene red during the aerobic reoxidation of methyl blue leucoform. On the contrary atmospheric oxygen inhibited methyl red degradation in the solution of ascorbic acid, which is an example of colouring agents degradation under the anaerobic conditions. The examples of positive and negative action of reducing agents during the production of beer and significant role of beer colouring agents during its ageing is being stated here.

Keywords: beer ageing, Fenton reaction, activators, colouring matter, phenylalanine, ascorbic acid

Published: May 1, 2003