A Technological Solution to Modulate the Aroma Profile during Beer Fermentation

During the production of fermented alcoholic beverages, such as wine or beer, the loss of aroma active compounds (AACs) has a significant impact on the overall product aroma. This paper presents the results of an experimental technique in which a condenser was placed on the top of the fermenter in order to reduce such losses. AAC concentrations in beers produced in this way were compared with a control produced without a condenser. There were two main findings: (i) some AACs could be recovered during fermentation and (ii) the technique stimulated the de novo synthesis of esters from carboxylic acids and alcohols. In particular, the production of ethyl esters from the reaction between ethanol and organic acids and the production of acetates from the reaction between acetic acid and alcohols were demonstrated. Consequently, the addition of the condenser changed the final aroma of the beverage. The effect was confirmed by a panel test and AAC quantitation using HS-SPME-GC-MS. The technique could be used by brewers as a tool to modulate the flavor and aroma of beer.