Ask Mr. Wizard

CO2 Flushing


Bill Serowski - Hamburg, New York asks,

I always hear that CO2 is heavier than air, but I am no scientist. Just how much heavier than air is it? I would like to know if the method of injecting a little CO2 into a carboy before transferring or blasting a little into a bottle before bottling has any impact on keeping the oxygen out of your finished beer? I have a vision in my head of this blanket of CO2 sitting in the bottom of a carboy or a bottle, then filling them from the bottom up where the beer nicely stays under the blanket of CO2 and eventually all the oxygen gets pushed out as the level rises in the carboy or bottle. Is this really what is happening?

Oh boy, this topic is one that I have some pretty strong thoughts about! I will start by throwing out a few numbers to answer your question about gas weight and density.
Response by Ashton Lewis.