Airlock Activity Is Not Necessarily A Sign Of Active Fermentation

I have been on a fairly aggressive brewing schedule recently. With some great events and competitions coming up in the next few months, I've had to brew fairly frequently to keep up with the beers that I've already promised or plan to enter into competition. One of those beers I waited until the last possible moment to brew so that it would be ready for the style showcase at this month's Brewminaries meeting. The beer style I was assigned was American Stout. It is one of my favorite styles to brew. Added to that, it's always a hit at this time of year. It's partially for that reason that I was excited to brew it. I'm also excited to share the beer at our meeting in about a week and a half. 

I waited until the last minute because I felt that super fresh was the way to go in order to highlight the citrusy hops and dark malty notes of chocolate and roast.  Given that I waited until the last minute, the fermentation schedule had to go according to plan. 

American Stout wort being lautered into the kettle. 

American Stout wort being lautered into the kettle. 

With an original gravity (OG) of 1.070 and with the alcohol by volume (ABV) of the beer projected to be north of 7%, I wanted a healthy pitch. I began 3 days before brew day by propagating some Wyeast American Ale II (1272) yeast in a 1.5 liter starter. I kept it on a stir plate for 48 hours before cold crashing overnight in my lager chamber, decanting, and then bringing up to room temperature to pitch. 

I'm a big fan of Wyeast 1272 which is rumored to the strain Anchor Brewing uses in Liberty Ale. I find that pedigree can begin to explain why, in my experience, I find it to be super tolerant in its temperature range without developing significant off-flavors. This is especially helpful in the summer when temperatures in my ale chamber can hover in the upper 70s. It's for that reason that 1272 has sort of become my house strain for most American-style ales. Since I ferment with it often, I know to affix a blow-off tube to my fermenter in anticipation of vigorous fermentation activity. 

My brew day went as planned, though my mash efficiency was a bit lower than I expected. I ended up with an OG of 1.066 and think the cause was from a last minute decision to fly sparge instead of batch sparge. Other than that, I didn't deviate from what was otherwise a pretty routine brew day. I got a late start to my brew day so when I finished brewing that night I transferred my wort to the fermenter, oxygenated it with a stone, pitched the yeast, covered it with a lid, attached the blow off tube, and put it away.

American Stout in back with blow off tubing attached. 

American Stout in back with blow off tubing attached. 

In the morning, there was no airlock activity. Not a single bubble. I usually see airlock activity within about 3-4 hours since I developed the habit of incorporating yeast starters. Odd, I thought to myself, but nothing to worry about just yet. When I came home that night, I opened my chamber and... still no activity. And no sign of activity either. The sanitized water that the blow-off tube was in was not foamy or bubbly. I pressed on the lid there was no air pushing out. The next day, I really began to worry. I knew I had started with a fresh pack of yeast. I had also used the Mr Malty yeast starter calculator to get the right starter size. I even oxygenated the wort with pure oxygen. It just didn't make sense to me.

I began to panic. As I said, this beer had a limited window in which to ferment and was expected to be ready for a club meeting. I quickly revised my yeast starter schedule to move another starter of 1272 and use to re-pitch. It was such a bummer too as I was going to use that starter for a double IPA that I plan to enter into Homebrew Alley. This mystery was throwing the whole schedule on its head and very well might eliminate a beer I planned to make given deadlines.  

Then it occurred to me to take a gravity reading. It's advice I often give to panicked homebrewers who are in situations similar to the one I had found myself in. I grabbed my test jar and pulled a sample from the bucket's spigot. I was immediately hit with citrus and chocolate and the jet black, inky liquid was effervescent, a sure sign of yeast activity. I dropped in my hydrometer and sure enough I was at 1.020 on day 3. 

Everything is right on schedule! 

Everything is right on schedule! 

My panic ended up being a hilarious reminder that airlock activity can be but is not always a sign of active fermentation. It's not lost on me that it hadn't occur to me to follow the advice I frequently give as an employee of my local homebrew shop (LHBS). With any luck, it should be ready just in time for me to be able to share it at the showcase.