In this paper, a general CFD tool has been employed for the first time to describe the diffusion and loss of CO2 through an actual polyethylene terephthalate bottle, while experimental measurements have been performed to validate the model and establish its accuracy. The objectives of the study were to employ a generally applicable framework of transport phenomena to the assessment of carbonation depletion and related product shelf life, by exploring the effects of thermal regimes, initial carbonation, and bottle thickness non-uniformity.