Research On Improving Beer Flavor Quality Of Red Rock Beer

"Light and soft" was the characteristic of the red rock beer flavor.The beer flavor was improved in this thesis in the large-scale production with the actual situation of enterprise aiming the shortcoming of red rock beer flavor,such as reducing the ratio of higher alcohol to ester,the content of aldehyde and acetic acid,and optimizing the ion content.The main conclusions were as follows:The ratio of higher alcohol to ester of beer was influenced greatly by the oxygen content of wort.The ratio of higher alcohol to ester of final beer could be decreased after the oxygen content of wort was reduced,then the soft taste of beer could be increased.The ratio of higher alcohol to ester could be controlled below 5.5 when the oxygen content was fitted 15 mg/L (computer index).The ratio was reached 98%which the ratio of higher alcohol to ester of red rock beer was produced in 100 M³ line.The aldehyde content of beer was affected by the wort pH value.It was found that there was positive Pearson relationship between wort pH value and aldehyde content of red rock beer.The aldehyde content could be decreased greatly by increasing the dosage of phosphoric acid in mashing.It could also be reduced with 15 mg/L oxygen content in wort.The sugar composition was not influenced,but the amino acid composition of wort was influenced greatly after mashing process adjustment.The content of Ca²⁺,Mg²⁺,Cl^- and SO₄^2- was relative stable,the corresponding ion content of wort and beer was not influenced obviously.The content of Ca²⁺ and Mg²⁺ in 10°p wort was 45-50mg/L and 70-90mg/L,respectively.It was the key reason that the difference of content of Cl^- and SO₄^2- in malt which result in the ion content change of 7°P red rock beer.The acetic content was different with different kinds of malt.The acetic acid content of Canadian malt(metcalfe) was higher than the content of Australian malt(stirling).The acetic content of wort was increased greatly during wort filtration,and was decreased 33.8%after wort boiling.It could be decreased greatly after adding 0.3 mg/L ZnCl₂(the same wort),and the fermentation speed was improved greatly.There was significant positive relationship between beer pH value and acetic acid content.The acetic acid content could be reduced after beer pH value was decreased in the production.There was positive relationship between acetic acid and acid taste.