Influence of alpha acids hop homologues of bitter and aromatic varieties on beer quality

Introduction. The aim of the study was to study the bitter substances of hops to establish the dependence of the bitterness of the wort and the quality of beer hops on the quantitative and qualitative composition of alpha-acids hop homologues, in particular, on the content of cohumulone in alpha-acids. Materials and methods. Aromatic and bitter hops with different content of cohumulone in the composition of alpha-acids and beer made from it were studied. High-performance liquid chromatography was used to determine the amount and composition of hop bitter substances and products of their transformation in the brewing process as well as spectrophotometric methods of quality control of the bitterness of hopped wort and finished beer. Results and discussion. It is noted that alpha-acids of the studied varieties contain a wide range of cohumulone content: from 19.6% in hops of Alta variety to 43.8% in hops of Ruslan variety. Establishing the relationship between the quantity and quality of bitter substances of hops and the bitterness and quality of hopped wort and beer show that with increasing mass fraction of cohumulone in the composition of alpha-acids of aromatic hops by 1% with a ratio of beta-acids to alpha-acids of 1.11-1.34 the value of bitterness of the wort hopped by them increases from 0.69% for Gaidamats'kyi variety to 1.05% for Slovyanka variety. In bitter hops, the ratio of beta-acids to alpha-acids is much lower and is 0.51-0.74. Analysis of the relationship between the growth of cohumulone and the change in the bitterness of the wort hopped with bitter varieties shows that with increasing the share of cohumulone in the alpha-acids of bitter hops by 1% the bitterness of hop wort increases from 0.19% for Ruslan to 0.38% for the variety Promin'. Between the bitterness of the wort and the amount of cohumulone with hops when using both bitter and aromatic varieties, there is a strong relationship as evidenced by the correlation coefficient which is for bitter varieties r = 0.90 +/- 0.10, for aromatic r = 0.98 +/- 0.20. In the formation of the bitterness of the wort, hopped with aromatic varieties from the ratio of beta-acids to alpha-acids is more than one, the role of beta-acid compounds is much higher compared to bitter varieties. Conclusions. When used for hop wort of bitter type hops with different composition of alpha-acids, their use is more effective in varieties with a high content of cohumulone.