Originally Posted by
MSPeconomist
Pouring it back into the bottle isn't good for the quality of quantity of bubbles, even if it hasn't been exposed to someone's germs.
Quality of bubbles is much more to do with deliberate imperfections micro-etched into the surface of glassware, rather than gas content.
Quantity of course is a different matter - an open bottle is worse because the surface area in contact with air is wider in the middle of the bottle than with the flute due to the flute being tall and thin, and the surface area in contact with air is the critical factor more than glass imperfections causing pearling and CO2 to come out of solution.
If EK served in coupes that would be a different matter.