why not air?

[xscash]

i tried to search for this, but found nothing.
party pumps pump air into the keg....why do we not used compressed air instead of co2 when using a tap system?
just looking to further my knowlege

[edramshaw]

Air will change the flavor of the beer, from both oxygenating it and from introducing spoiling bacteria. Party pumps work (and so would using air in your system) only if the beer is consumed within a short period of time (8 hours or so). The other issue is that the CO2 is absorbed into the liquid which maintains the proper carbonation levels, using air would (I assume) let the beer go flat after a day or two.

[xscash]

thanks for the info...i figured that it would spoil the beer. but the going flat has me puzzled. if you put the proper pressure on the liquid.....the co2 could still come out?. i didnt know that.
thanks again.

[Scott Zuhse]

Laws of gases dictate equalization of partial pressure.