text: Can dry hopping cause overflow? - Home Brew Forums
  > Can dry hopping cause overflow?
  Just racked into my secondary (5 g carboy) after 5 days in primary. Trying dry hopping for the first time. Concerned about how there is about 1-2 inches from the air-lock. I just racked about an hour ago.
  Has anyone experienced an overflow in the secondary due to dry hopping? I added 1 ounce of cascade pellets by the way. If it does start to overflow should I remove the air-lock? I don't have a blow off tube available to what else would be a good option to avoid the risk of contamination?
  Ive never had any overflows in the secondary
  If anything you'll get mild bubbling. As long as you didn't have a stuck fermentation for some reason, which is unlikely. I bet that carboy looks purdy
  Definitely no stuck fermentation, SG was down to 1.010 at racking. I think it may just hang on. It is oh so perdy.
  If it didn't out-gas and overflow when you added the pellets, you're safe.
  I've actually heard from a Pro Brewer that dry hopping can cause overflow even as the fermentation stalls. I don't know the reason, and it'a anecdotal but I believe it is possible. He's had a few explosions so he waits until it's totally done then dry hops.
  It's always a good idea to wait to dry hop until after fermentation is complete, whether in primary or secondary. The CO2 being produced can drive off the flavor/aroma oils.
  +1, you jive turkey!
  [/1970s blaxploitation film accent]
  Not only does CO2 off-gassing scrub volatile, aromatic hops oils, the pellets breaking apart add an almost infinite amount of nucleation sites where even more CO2 can devolve. That can cause a nice gush of green, nasty foam.
  I do have a decent layer of this green foam. Is it noob of me to think that this was normal? Will this fall back in like the krausen? or stay on top... and how will it affect the final product