A misconception lingers in the minds of some wine consumers that Champagne wines should not age much after the minimum period of 15 months in contact with dead yeasts, known as maturation on lees. It is certainly a myth, as far as the best cuvees are concerned. Dissolved CO2 being responsible for bubble formation in sparkling wines, keeping it as efficiently as possible in the sealed bottles during aging is therefore a challenge of importance for old vintages likely to mature on lees for several decades. Measurements of dissolved CO2 were done on an outstanding vertical collection of successive vintages from a prestige cuvee, showing maturation on lees ranging from several months up to 35 years at a constant temperature of 12 degrees C. Progressive losses of dissolved CO2 during aging on lees were evidenced and discussed on the basis of a previously developed exponential-decay type model taking into account the main geometrical parameters of both the cork and bottle. The prestige cuvee (with a narrow bottleneck, and sealed with premium natural cork stoppers) was found to hold much more efficiently dissolved CO2 during aging than a batch of standard Champagne and sparkling wines bottles showing 3 mm wider bottlenecks. By fitting our data with the exponential-decay model, the diffusion coefficient of gas-phase CO2 through the cork stoppers used to seal this prestige cuvee was found to range between about 5 x 10(-11) and 9 x 10(-11) m(2) s(-1). Moreover, by extrapolating the data well beyond the measurement range, it was suggested that very long maturation on lees of the order of 76 +/- 19 years should be needed to decrease the level of dissolved CO2 in the prestige cuvee below the critical concentration required for bubbling. (C) 2018 Elsevier Ltd. All rights reserved.