Wort Composition and Beer Flavour. I. The Influence of Some Amino Acids on the Formation of Higher Aliphatic Alcohols and Esters

Wort, to which was added various amounts of glucose solution containing either (NH4)2SO4 or one of the amino acids alanine, leucine, isoleucine, valine or proline, was fermented, and in the resulting beers the concentrations of ethyl acetate, isoamyl acetate, n-propanol, isobutanol, and amyl alcohols were determined by gas chromatography. The nitrogen source had some effect on the formation of higher alcohols, in addition to the effect due to conversion of some of the amino acids to the corresponding alcohols via the Ehrlich pathway. Ethyl acetate formation was not significantly affected by the nitrogen source, and iso-amyl acetate formation increased when amyl alcohol formation increased.