Tank vs. Keg aging
I currently have a 2-week-old Porter in the brite tank (brite, but not sterile filtered and carbonated), which I am holding at 2oC or so to 'age'. The request from the bar is 'get it on tap as soon as possible'! I am considering racking one keg off so as to keep the bar happy, however I am not convinced the beer is at it's best yet.
My question is, is there any difference between cold aging in the brite tank or in kegs? In other words, should I keep as much as possible in the brite tank for as long as possible, only kegging as I need to, or should I just keg it all in one hit and keep the kegs in the coolroom to achieve the same aging effect? There is no further filtering or processing required, so it's really just a matter of keeping the beer in one big 'keg' vs. in individual serving kegs ... or not?
Beer maturation. A most venerable, and often somewhat controversial topic!
First step, move the beer off the yeast into a secondary conditioning vessel. Next, it is my belief (and I'm at the brewery now, away from any supporting texts, so without, for the moment, any backup) that one of the many variables in the beer maturation equation is the size and shape of the vessel. Beer matures differently in a tall thin tank than a short shallow tank, than a cask, than a keg, than a 750 ml bottle, than a 12 oz bottle.
I also believe the larger the vessel, the mellower (a vague nonscientific concept to be sure) the maturation, and consequently the smoother and more refined the resulting beer.
That being said, and with tank space usually very limited, over the years it has been common practice in my breweries to rack unfiltered beer out of a conditioning tank after a few weeks into kegs for further maturation. Usually this is with bigger beers, Imperial stouts, barleywines, strong Belgian ales, Scotch ales and the like. Scotch ale in particular seems to have a nicer profile after a few (say three) months in the conditioning tank, but with only so many tanks...you do what you have to do. Most of these beers will then spend six months to a year in the keg before serving. For barleywines, Belgian ales, and stouts this usually works beautifully.
I have done experiments similar to what you are proposing, keg some, leave the rest to mature further. In all these cases, any difference was difficult to determine, so it became my method to leave it in the tank as long as possible (until I needed the tank for something else!), then just keg it all off, and tuck it in a corner of the cold room until "ready". Different from how it would have been if left in the tank for the entire year, but good nonetheless!
The answer: A common practice, but the beer will be different.
Some help, or no help at all?
keg it up
If you have already filtered the beer then I would recommend serving it as soon as possible. The flavor changes that could have taken place with the yeast re-absording volitales will not happen now or very little will depending on how tight the filtration. I am not a big from of 2 week beers but space and cost dictate otherwise so it may have to be done. If you can let you beer age unfiltered then I know you will see flavor changes but right now you want to get that beer on tap and out the door.
On a side note I have aged beers from 6-12 months yeasting off often (once a week or so). These beer were in the 20-26 plato range and I have had great results with this. That being said I have also made these beers on short notice and been able to turn then over in 4 weeks with a lot of the flavor profiles that I wanted. If it is a seasonal most people won't be able to tell the difference from previous years but if it is a regular beer they may pick up on the flavor changes. Most consumers will tell you they can taste the difference from batch to batch but you will be the ultimate judge on that.
Hope this helps
The biggest problem you face is keg cleaning. Can you guarantee that all of your kegs are as clean as your single aging tank? Even at cold temps you still have the potential for something to go wrong. I would age in the large tank.
You should be the judge of if your beer is ready or not. Don't sell beer that may not be at its best. Go for quality over a quick buck.
Simply due to production schedules, we've been aging in kegs for years. If you have the capacity to store the kegs cold, that is. I'm already making the assumption your keg cleaning process is capable. We've stored beer for a few years (special editions) and served them with little deterioration..........but you always feel a snick skiddish when you first tap it. Storing Ales for a few months has never been a problem for us.
I would have to add that if you're producing Lagers, though, bulk aging tastes better in my humble opinion.