ABSTRACT
Typical beer flavor and aroma are the result of a fine and subtle balance between numerous flavor-active compounds that originate from the raw materials used in the brewing process, together with those originating from yeast during fermentation. Groups of volatiles caused by microorganism contamination normally impact negatively on beer aroma, but for some beer types, such aromas are desirable. During the brewing process, hops are added into the boiling wort to provide a bitter taste and aroma to the final product. Post-linalool aroma depends on the time of hop exposure to elevated temperatures, which leads to racemization and evaporation, and on the presence of yeast enzymes for degradation of linalool-containing glucosinolate. Aldehydes are responsible for the grassy notes in beer aroma. Esters are responsible for the fruity/solvent aroma in beer. Ester compounds are the result of a reaction between higher alcohols and organic acids. The winy aroma in aged beers is a result of the esterification of methyl butyric acid.
