Abstract: The effects of 8 amino acids supplemented at 50%, 100%, and 200% of the original amounts (Met, Phe, Trp, Arg, His, Ile, Leu, and Lys) on the fermentation performance of yeast during high gravity brewing (24 °P) were studied. The results showed that amino acid supplementations significantly increased wort fermentability and ethanol yield, promoted yeast cell growth, and improved yeast cell viability and beer color value. High gravity wort supplemented with 100% of amino acids exhibited better fermentation performance in terms of wort fermentability, ethanol yield, maximum number of suspended cells and cell viability, which increased by 6%, 17%, 11% and 10%, respectively, compared with those of the control. Furthermore, the color of diluted beer supplemented with 100% of amino acids was still bright, and exhibited the minimum color difference ΔE value, which was most similar to Qingdao draft beer.

Key words: high gravity brewing, amino acids, physiological characteristics, fermentation performance, brewer’s yeast, color value