Ah, very enlightening. Thanks!
Updating this thread. I just made pull #4 from the 11gL barrel originally started March 2009. I let time slip away, pull #3 was nearly two years prior. This pull is a full four years from the time I started this project. I still had some of pull 3 in a keg, so I decided to rack some pull 4 into this keg. I tasted pull 4 and it was very nice! Super tart and a real cherry flavor. I also racked a few gallons into a carboy for bottling, then I replaced the missing beer with 6gal of new beer. I made a brown ale using a generous portion of special B, choice debit termed hops and fermented with a British ale yeast. I also added 2L of unfermented wort as an experiment to “feed the bugs”.
No sign of problems, so on we go I guess.
Like!
The unfermented wort was a bit of a mistake, next day I pulled the pressure relief plug on the silicone bung and yeasty goop shot out. Probably shouldn’t have filled it quite as full as I did. It settled down by the following day at least. I wasn’t sure how active the Sacch yeast would be in the acidic environment, apparently they are just fine.