Old CO2 Acrid taste?

[johnnyc]

So...I got my kegging equipment last night. New everything except for a 20# co2 tank my friend had from when he abandoned brewing. (shame on him) Anyway the tank is from a pepsi guy but my friend has had it for a couple years. Its full so I hooked it up last night. I have had 2 beers crash cooling at 35* for about a week so I racked them to kegs and turned up the gauge to 30 psi. I rolled and shook them for about 10 min or so then put them in the keezer at 44*. Today I vented the excess and reset the gauge to 12psi.

I've pulled out of both kegs and I have an acrid, bitter taste. Does CO2 get old? To be exact one keg spent the night on gas at 30psi and one off gas at 30psi. I vented them both and reset the gauge at 12. They're both acrid and I'm not sure why. I would say its a green beer but they're both over a month old. Obviously the answer is RDWHAHB but I'm curious if I'll need to vent a lot to get the acidy down or if it will mellow. Will that co2 fizz mellow? I debated swapping out the tank for another but since it is full...

Advice?

 

[david_42]

CO2 doesn't get old, but carbonic acid is acid. Give the beer a couple days to adjust to the pH change and it should be fine.

 

[Bobby_M]

+1, fast carb = a lot of carbonic acid all at once.

 

[johnnyc]

Good to hear. So in a week or so it will be the same as it would be if it was long carbed at 10-12psi? Also I guess this is to be expected in any beer I carbonate quickly?

 

[david_42]

Yes
Correct

 

[johnnyc]

So after a week at 10-12psi the taste had mellowed out a lot, almost not noticeable. But a few days later it was back again, very strong. I'm not sure what to do because I can't drink it like this. I've got some new brews coming up and I don't want them to go the say way. Should I disconnect these from the gas and let them sit for a while? Hate to be w/o homebrew but if aging these off the gas will help I'll make the sacrifice.

 

[Bobby_M]

It could be overcarbed.

 

[johnnyc]

Perhaps but I dropped it down from 30 to 12psi after one day. I can vent it a few times over the next few days to see if that helps. I guess I'll try that and drop the pressure to 8psi to see what happens. When I pour I get around 3/4-1" of head on a 20oz glass. None of the foaming issues I hear others talking about. I'll try this and update later this week.

Thanks for the advice. Regardless of the current issues having kegs is awesome