cooked up a lager in late Feb, ran thru primary fermentation at about 55F for 8 days, with a 2 day acetyl rest. Then racked to secondary on 3/7, and put in slowly cooled to 33F. Pulled it out of the fridge last night for bottling but, lo and behold, as the carboy sat on my kitchen counter, the airlock started bubbling @ about a bubble every 3-5 sec, and the beer in the carboy developed a lovely 1/2 inch frothy head. Still has a bit of a head on it today, with some airlock activity.
Before racking, there really was no more activity, esp after the diacetyl rest. And the foam i observe today sure looks like a beer head, nor krausen.
Is this something that is expected w/lagers fresh from the fridge? Some kind of de-gassing phenomenon? i aborted my bottling mission for concern about bottle bombs; can't find any reference to this phenomenon in ny suds books.