Dry hopping

I know this is probably a rookie question but, just did my first dry hopping after two weeks of secondary and started getting bubbles out of the airlock. I don’t quite understand this. Seems like fermentation has restarted. Why?

It’s just CO2 coming out of solution.

Thanks, that helps. If it is a normal occurrence then I am okay. I just don’t understand the chemistry of it. I’m not adding yeast or sugar so why would fermentation start back up?

The hops create a nucleation site the absorbed CO2 can come out of solution and attach to. Also, beer can only hold a certain amount of CO2 in solution at a certain temperature. As the liquid warms, it can’t hold as much so the gas is released. Agitation can also knock some of the gas out. :mrgreen:

Got it, thank you all