Oak-driven infection?

I brewed a porter nearly two months ago. After two weeks in "primary", I transferred the beer into secondary onto oak cubes which had been soaking in whiskey for three days. The cubes were purchased new and transferred directly from their plastic bag into the whiskey. Other than soaking them in whiskey, I made no attempt to sanitize or sterilize the cubes.

Once transferred, the (glass) carboy was quite full and the cubes were half-submerged half-floating in a thick mass near the top where they practically block the neck.

About a week later, I noticed that there were quite a few bubbles forming around the oak. Given that I had reached my expected FG, I chalked this up to the oak somehow stimulating release of CO2 which had been dissolved in the beer. But the volume of bubbles continued to increase, and even now, they're streaming up into a thick layer of foam in the neck of the carboy.

Roughly two weeks ago, I took a very small sample and tasted it. It was delicious and not at all sour. In fact, I might consider bottling it now if I weren't concerned about the continued bubbling...

What kinds of tests can I perform to figure out what's going on?

Am I right to assume that it doesn't make any sense whatsoever to package the result as long as there's such visible gas production?

 

Take another gravity reading. If it is still moving then you should wait. I doubt it is any infection from the oak, especially if you soaked them in whiskey. If there is an infection it may just be existing bugs in your beer, pre-oak. If it is good, and infected, it may give you something very good in a year, think rodenbach vintage but darker and roaster. I have had some sour stout beers that have knocked my socks off.

Typically if you intend to dose some bugs in a beer you shouldn't' bottle above 1.007 or so as the attenuation can cause bottle bombs. Unintentional infection though, there is no telling what bugs are in and what metabolic process they have... If you can, keg it and keep it cold to stop any more progress.

 

The wood provides nucleation points for the CO2 to release out of suspension, so if there's no off flavors, that is the most likely explanation.

 

As edecambra mentioned, if the gravity is stable and the beer smells and tastes fine then you have no worries

 

I took a gravity reading last weekend and got 1.009. When I put it into secondary, it had been 1.014 -- which was also the FG predicted by BeerSmith. So it definitely hadn't finished fermenting at that point.

The reading I took today was more like 1.008, but that may well reflect the limits of my ability to read a hydrometer rather than continued activity. It still tastes great with no off flavors, and it's still producing bubbles...