Control Of Ratio Of Higher Alcohol To Ester Of Beer In Large Fermentation Tank

The ratio of higher alcohol to ester of was one of the most important factors which was caused "headache" after drinking. The larger the volume of fermentation tank was, the higher the ratio of higher alcohol to ester of beer was. It was more and more large with the The ratio of higher alcohol to ester of beer in large fermentation tank in the storage of fermented liquid was researched in this thesis. The main factors which the ratio of higher alcohol to ester was found and they were optimized systematically. The aim was that the ratio of higher alcohol to ester which was fermented in the large tank was decreased and as similar as that in the small fermentation tank. The factors which the ratio of higher alcohol to ester of fermented liquid were influenced was analyzed during the storage.It was found that the main factors which the ratio of higher alcohol to ester were yeast pitching volume, wort oxygenation, sugar consummation time, fermentation temperature at the beginning and diacetyl reduction time after research. There was the negative relationship between sugar consummation, the yeast pitching volume and wort oxygenation with the ratio of higher alcohol to ester, while there was the positive relationship between fermentation temperature at the beginning and diacetyl reduction time with the ratio of higher alcohol to ester. The content of unsaturated fatty acid and amino acid of wort was different with different mashing workshop, resulting in that the ratio of the higher alcohol to ester of fermented liquid was different. The ratio of higher alcohol to ester was different with different fermentation tank volume.In contrast study, the mainly influence factors on ratio of alcohol to ester is yeast pitching, the oxygen content of wort the time of sugar degradation, full tank temperature and the time of VDK. The time of sugar degradation is negative correlation, and the others is positive correlation. The ratio of alcohol to ester of fermented liquid was different which was fermented by wort with different content of unsaturated fatty acid and amino acid in different mashing workshop. The difference of large and small fermentation tank make the difference of ratio of alcohol to ester.The processing was optimized to adjust the ratio of higher alcohol to ester. The yeast pitching volume was decreased, the wort oxygen content was increased certainly, the pressure of fermentation tank and the main fermentation temperature were decreased, the fermented liquid was stripped by CO₂. The ratio of higher alcohol to ester in large fermentation tank could be decreased by all of these methods. The ratio of higher alcohol to ester in the large fermentation tank was kept consistency with in the small tank.It was found that the ratio of higher alcohol to ester was influenced much greater by anaerobic bacteria than aerobic bacteria. The ratio of higher alcohol to ester of fermented liquid was little effected when the anaerobic bacteria were less than 5/mL.