Bourbon Barrel Porter, long fermentation

I have a strangely long fermentation going with a modified NB Bourbon Porter extract kit. I’ve used this exact recipe before, and had no issues. I also consider it the best brew winter brew I’ve had. There were no changes in my techniques or procedures, sanitation and prep was done as per the norm.

First, the modifications:

I use a 1 gal freezer bag of charred white oak chips that were used to make bourbon (2 batches of bourbon, 1 month per batch). They have been soaked in bourbon that is around 150-170 proof in individual jars so the risk of infection is quite low. I freeze the oak chips to store them, even the condensation is so high in alcohol that a deep-freeze doesn’t freeze it.

I also split and soak 2 mexican vanilla beans in the same bourbon (a few oz at best, only enough to keep the beans completely covered) for a week.

I pitched a yeast starter so initial fermentation was quick (first noticed it around 5-6 hours) and aggressive. After 7 days, fermentation had slowed enough that I moved it to secondary on Sept. 20th along with the oak and vanilla. I didn’t move it based on a gravity reading, I tend to move to secondary a little before the brew has finished fermentation anyway, to help purge any O2 that didn’t get purged with my CO2.

Light fermentation picked up in the secondary and is still producing micro-bubbles, 2.5 weeks later. I don’t have a thief so I haven’t sampled it, but the airlock doesn’t smell fouled. Quite the contrary, it smells amazing.

I’ve never had this sort of action in a secondary fermenter. The temp has been at a consistent 70-71 degrees the entire time. Do I have reason to be worried? This is one of the brews I take hunting every year, it would be quite a disappointment to the crew if they had to skip out on a year. :slight_smile:


Couple things could be going on here. First, you might have roused some yeast during racking, coupled with some aeration could possibly get the yeast going to drop another point or two. The second thing is that your beer is probably done, and the oak chips are providing nucleation sites for CO2 to come out of solution, making it look like it’s still going. A change in the weather and drop in atmospheric pressure can do the same thing.

Check with your hydrometer over a couple of days to see if gravity is dropping still. If not, then you just have some CO2 coming out of solution. Nothing to worry about. If it is still dropping, and drops below your expected final gravity, then there may be reason to worry but I bet it’s just fine.