CO₂ Retention: Zahm & Nagel Method

Purpose

This procedure determines the CO₂ shelf life of a given carbonated beverage container by evaluating the CO₂ level within sample bottles over time using a Zahm & Nagel test device.

Description

One hundred and twenty bottles are carbonated to 4.2° ± 0.1 volumes CO₂ and then stored in a constant temperature chamber at 72°F, 50% RH for the duration of the test procedure. Twelve bottle samples are destructively evaluated using the Zahm & Nagel device for internal pressure and temperature at the following intervals: 0 hrs, 24 hrs, 2, 4, 6, 9, 12, 16, 20 and 24 weeks. The internal pressure and temperature are then correlated to the CO₂ volumes contained within the bottle and the average % CO2 loss per week is determined. This test measures the CO₂ loss from the entire package (bottle and closure) not just the bottle alone.

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