Sanke Keg Carbonation and Oxidation

[Mark_tries_brewing]

I have two questions related to sanke kegs. I am not sure where to put this question so I went with general beer.

First, why does beer and sanke kegs not carbonate? If you have experience otherwise please post, however in talking with multiple brewers and bar owners it seems that a beer carbed to say 15psi, even when pushed at a higher pressure to overcome distance or elevation, does not end up overcarbed. Why does this happen? I have used corney's for my homebrewing and had very different results (we couldn't force carb if this was the case).

Second, in both my own experience and in talking to a knowledgeable local bar owner, beer in kegs does not cellar well. Obviously over a long time (multiple years) a bottled beer can lose some/ most carbonation and only certain styles really age well but nothing like the drop off the kegged beer seems to exhibit. In theory a keg should be the best way to store beer but this is not the case in my/ his experience. The most common problem would be oxidation. Can anyone explain why this happens? The only differences I can think of are a stainless steel vs glass container and the fact that a keg has a stem but neither of these seem to explain when kegs do not cellar as well as bottles.

 

[Phunhog]

You bring up an interesting question regarding why kegs with long draw lines don't over carbonate. I know my local craft beer bar has lines that almost 100 ft in length and they run along the ceiling!! It must take quite a bit of pressure to overcome the head pressure/friction loss. It must be something obvious though since the kegs don't over carbonate.

 

[chickypad]

Pretty sure that most bars with really long lines like that use beer gas to push the beer, so they can set it at a much higher pressure but the partial pressure of just the CO2 will be in line with the beer's carbonation level. I've not experienced the beer going bad in kegs myself. I'm drinking the second keg of a big stout right now that is about 18 months old. If anything it's better than ever. More of a style issue than what type of package it's in IME.

 

[Mark_tries_brewing]

I should have specified with regards to aging I was referring to commercial beer in sanke kegs. These questions were mostly prompted by a conversation with a rather astute bar owner who has observed over time (with many vintages/breweries/styles) that kegged beer just does not cellar in the same way bottled beer does. Also he has tried the same beer, aged for the same amount of time, and continually found the kegged beer doesn't hold up while the carb on the bottles might drop a bit the beer is still great.