Pasteurization of beer by a continuous dense-phase CO2 system

Effects on beer quality were studied after pasteurization by a continuous dense-phase carbon dioxide (DPCD) system. Changes in haze formation, foaming capacity and stability, and objective and subjective aroma and flavor were evaluated, after validation of a 5-log reduction in yeast populations. A maximum log reduction in yeast populations of 7.38 logs was predicted at 26.5 MPa, 21 degrees C, 9.6% CO2, and 4.77 min residence time. Haze was reduced by DPCD pasteurization from 146 nephelometric turbidity units (NTU) to 95 NTU. At this same treatment combination, aroma and flavor of beer sample means were not considered significantly different (P = 0.3415) from fresh beer sample means when evaluated in a difference from control test, using fresh beer as the reference. Foam capacity and stability were affected minimally by CO2 processing; however, changes would most likely be unnoticed by consumers.