After all the gushing that I suffered last year at this time, which I thought I had tracked down to the used plastic conical I purchased, I fear that it may have a new infected batch. My second runnings beer is quite phenolic and tart, and it gushes when opened. I have some bottles in the fridge and some stored in the garage. Fridge is holding at 35*F, garage is floating in the 40s. The garage bottle gushed out for over an hour, slowly. The fridge bottle foamed up quite a bit up to the lip but never gushed over the edge. I repitched the yeast from my Fresh Hop Brown Ale for this batch, as well as my Wee Heavy that this beer came from. The Wee Heavy doesn't seem to be showing any off flavors or over carbonating, but it was in the secondary for a month longer than this one. Also, the Brown Ale is great, even after 4 months, no phenols, no tartness, no carbonation issues, so I am not sure what is happening with this new batch of gushers.
I did ferment it with oak which might have introduced something wild during the longer than expected lag phase.
Another possibility could be that since almost all of this batch was bottled in used swing tops that maybe the rubber grommets on the bottles had wild yeast on them from previous beers (a few of my sour Wits and Saisons, as well as last year's infected beers). I will be replacing all my grommets, boiling them before every new batch.
Now that I think about it, I did ferment this beer in a 5 gallon glass carboy, which I had my Lambic in for over a month prior to bottling to get it off the oak. With the lag phase, and the possibility of having some of those bugs in there, it's possible that this is the cause (I have since sold my 5 gallon glass carboys and switched to plastic).
No matter what caused it, I pray that I don't end up with the same issues as last year. Good thing I dumped the yeast after that batch and went with a brand new package of West Yorkshire on my IPA. I am getting a new SS racking cane and new tubing to replace my auto-siphon (which forced too much air into the beer before all this happened), and using my new CO2 tank to force transfer from here on out which should keep the infection from spreading to any new batches.