Expert: Henry Boyter - 3/22/2004

Question
Hello___...  My roomate and I are in the middle of a dispute about 2 liters of soda.  She believes that it is advantageous to "squeeze-out" excess air from the bottle before replacing the cap and storing in the refrigerator.  She believes that this longer preserves the "fizz" in the soda.  I believe the opposite to be true.  Which one of us are correct?   Thanks so much for your time and for helping us settle this bitter debate!

Answer
I don't think it makes a difference.  He is correct that the CO2 level in the cola will stay higher if there is no air.  But once the bottle is open in either case, it will quickly come to equilibrium with the atmosphere.  There may be a difference, but I don't think it would be measurable.  It may be greater if you compared a near full bottle versus an almost empty.  Now if you could put the bottle under pressure after you screw the cap back on, you might have something.  Try this, take a half full bottle, squeeze the air out and stick in the frig for two weeks.  See how much fizz is left when compared to one with air.  At $0.79 per bottle, it won't cost much.