I checked the gravity reading today and the beer is 1.015 to 1.012 which is right on target. It is in the primary, I'm brewing an IPA, I noticed a bit of bubbling on the surface of the brew and a very slight vinegar smell, though it could very well have been my imagination. The color looked fantastic and a friend of mine who has stuck around for the entire process did not pick up the scent of vinegar (he is a smoker and I am not) but I did. Does this sound like bacteria or am I a bit paranoid.