When I dry hop my beers that need dry hopping I use pellet hops and I just add them to my secondary. Then though out the secondary I shake my carboy to get the hops to move around instead of just sitting on top. My question is will its cause oxidation, or what will cause it.
There’s enough CO2 suspended in the beer that shaking it won’t add any appreciable oxygen. It will release CO2, which is why your airlock will bubble a lot when you shake the carboy. Unless you’re having trouble with hops staying on the top, I don’t think you need to shake the carboy. Usually, they’ll sit on top for a couple of days, and then they’ll fall down. If you only want a day or two with the hops, you may need to shake, but in that case, I’ve heard of people having good luck with putting the dry hops in a mesh bag with a bunch of sanitized marbles, and the bag will sink to the bottom and keep the hops from causing too much trouble.
Typically shaking of the carboy will cause CO2 to be released from the beer, which will essentially purge the headspace laeving only CO2, and making it very unlikely that oxidation will occur during your shaking.
To be sure however, I would suggest by gently swirling the beer in the carboy to release CO2 and purge the headspace prior to shaking it.
Yeast are great anti-oxidation agents. If you still have some healthy yeast in there don’t worry about a little oxidation.
