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The evolution of wine after bottling may be affected by the continuous supply of oxygen through the closures. I n the case of cork, oxygen may come from two different sources: permeation from outside through the cork and the release of gas from inside cork cells. I n this work we studied this later issue. The typical compression rate (volume change / uncompressed volume) of a cork stopper is about 40%. Taking in account that cork has a void volume ranging 70 to 80°/o cork cells pressure after bottling may reach 2 atm. This pressurized gas will 'escape' to both sides of the closure along many weeks. I n this work we measured the gas flow coming from cork stoppers in 3 typical starting headspace pressures: 60 mbar, 1000 mbar and 3000 mbar (absolute pressures). These conditions correspond roughly to vacuum bottling, balanced pressures bottling and bottling without any prior pumping. These experiments were performed by continuous monitoring the pressure, with a high accuracy gauge, in the headspace along several weeks keeping the bottleneck volume at constant temperature. In the case of vacuum bottling the headspace pressure continuously rises for many weeks. With balanced pressures, the pressure rises for a few days and then starts decreasing. I n the case of bottling without pumping the headspace pressure is typically higher than the cork cells pressure leading to a continuous pressure loss. These results together with those from permeation of cork provide a useful picture to those who need to know quantitavely the amount of oxygen in contact with wine in the post bottling period. (Bulletin de I'OIV, 2011, vol. 84, n0965-966-967, p. 261-269)
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