CO_2 Correction Factor for the Net Contents of Containers

摘要

A new formula to replace the current EBC formula for the correction of net contents in beer containers for the presence of CO_2 has been derived from a bibliographic study that reviews the influence of carbonation on beer density determinations. The study reviews the relationship between beer density and CO_2 partial molal volume (PMV) as defined by the American Society of Brewing Chemists (ASBC) (ASBC Methods of Analysis Fills-1 formula) and that given by the European Brewery Convention Analysis Committee (EBC) and shows that in the current EBC equation a CO_2 PMV of 0.65 mL/g and a residual CO_2 content after degassing of 0 v/v or % (m/m) is used. Experimental determination of CO_2 PMV gives values of 0.73 ± 0.01 mL/g for most of the standard European beers as Lager, Pilsener, Premium and Export styles. Residual CO_2 levels after decarbona-tion were quantified for a series of degassing methods and were found to be between 0.20 to 0.50 v/v average 0.40 v/v or 0.08% (m/m). A new equation for determining the CO_2 correction was then proposed assuming a PMV of 0.73 mL/g and a beer carbonation level of 0.40 v/v or 0.08% (m/m) after normal degassing. The new formula is recommended for inclusion in Ana-lytica-EBC replacing the current formula.