Avoiding CO2 overestimation: Selective measurement for reliable beverage control
Nonselective CO2 methods can overestimate the actual CO2 content of a beverage in the presence of air. Production batch data shows that the CO2-selective MVE method reveals the real CO2 value, independent of the gas mix.
Why nonselective CO2-methods can be misleading
Carbon dioxide (CO2) plays a central role in defining the sensory profile, stability, and specification compliance of carbonated beverages. CO2 measurements are essential for both quality assurance and process control. Although single pressure/temperature (p/T) measurement remains common in production due to its simplicity and low cost, it is inherently nonselective. The method measures total pressure and interprets it as CO2, even when other dissolved gases contribute to the measured pressure. The size of this deviation depends on the gas mix in the sample. Elevated levels of dissolved oxygen and nitrogen alter the gas composition of the beverage and directly impact analytical results obtained by nonselective methods. This makes the interpretation of nonselective CO2 results dependent on the process condition and the gas composition of the beverage.
The multiple volume expansion (MVE) method implemented in the Anton Paar CO2 meters enables selective CO2 determination, by separating the CO2 contribution from other dissolved gases. Under the tested conditions, this allows the real CO2 value to be determined independently of the gas mix. In addition, measurements combined with Total Package Oxygen (TPO) meter and Air Index values allow simultaneous evaluation of oxygen-related process conditions. This report evaluates two production batches with distinct oxygen levels to demonstrate the limitations of single p/T measurement and the diagnostic advantages of the MVE method.
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