I filled a bottle with one of my beers and brought it to my LHBS. He described it as phenolic. He also said it has somewhat of a metallic taste. He went over pretty much everything we talked about on this thread and gave me some new o-rings to replace on my keg. He said to take it apart and try using these. I've never taken apart a corny keg before so I hope it's not too much trouble. I'm thinking about dumping the batch that's been in the keg for a month since there's probably only half left. I'll change out the o-rings, sanitize everything, and try the water test by leaving some water in the keg overnight. If the taste is still there, I'm going to be pissed.