It’s a rare pleasure to be able to drink a bottle of champagne disgorged on the spot. This is only possible with bottles that are stored sur pointe: the bottles have already been riddled but not yet disgorged, and so are stored upside down with the sediment collected at the neck. Bottles that are stored sur pointe remain marvelously fresh for a very long time, partly because the lees, which are a natural antioxidant, are still in the bottle, and partly because the wine has never been exposed to the oxidative shock of disgorgement.
Disgorging by hand does require a bit of skill. As you slowly turn the bottle upright, the bubble of air trapped inside rises towards the neck. The idea is to remove the crown cap at the moment when the bubble is in the neck but below the sediment. Too early, and you lose a large volume of wine; too late, and the sediment falls back into the bottle, leaving you with cloudy wine.
Here’s a video of Jean-François Clouet, proprietor of Champagne André Clouet in Bouzy, disgorging a bottle of vintage 1995 for us to drink a couple of nights ago.