Originally Posted by logdrum
Matt Cole of Fatheads Brewery OTOH recommends dry hopping at 60-75% fermentation in order to drive off any O2 introduced by the hops. More than one way to peel an orange, I guess
Even at final gravity, beer will continue to produce trace amounts of CO2 sufficient to displace any oxygen. And while at a micro or commercial level, dumping in buckets of hops to a giant conical may agitate the beer enough to introduce O2, sprinkling on an ounce or two into your carboy probably will not prove an oxidation risk.
I always wait until final gravity before introducing dry hops.