Evaluation of Established Methods of Decarbonating Beer. Paul A. Smith and Lydia J. Marinelli, Miller Brewing Company, Milwaukee, WI 53201. J. Am. Soc. Brew. Chem. 50:0102, 1992.

Various methods of decarbonating beer were evaluated to identify the best method of preparing a beer sample for chemical analysis, particularly for the determination of alcohol and real extract. Beer samples were decarbonated by ultrasonic bath, filtration, a combination of ultrasonic bath and filtration, pouring (the repeated transfer of beer from one beaker to another), and ASBC method Beer-1A. The samples then were analyzed by a Servo Chem Automated Beer Analyzer for alcohol and real extract and by a LAN-1 carbonation analyzer for carbon dioxide. Samples prepared by ASBC method Beer-1A and the pouring method showed the lowest levels of carbon dioxide and real extract. An alcohol loss of from 0.05 to 0.07% (w/w) was observed in samples prepared by the pouring method; samples prepared by all other methods showed alcohol values within 0.02% (w/w), with samples prepared by ultrasonic bath tending to show the highest alcohol values. In addition, samples prepared by ultrasonic bath, filtration, and a combination of ultrasonic bath and filtration all showed approximately the same level of carbon dioxide and real extract. The error introduced by residual carbon dioxide in a sample was calculated to be approximately 0.0125% (w/w) real extract for each 0.1 volume of carbon dioxide.

Keywords: Alcohol, Carbon dioxide, Decarbonation, LAN-1 carbonation analyzer, Real extract, SCABA