I have had several bad batches of beer or so I thought so I put some beer out of the fermentor into soda bottles and carbed them up with those little carb tops. Then put the rest into kegs and naturally force carbed the kegs. Tasted the soda carbed beers and they were perfect, then the keg, good, but over time the beer gets worse. How to describe worse? The last batch was a killer citra pale, serious aroma, 5 days later seems to have lost most of the aroma. The bitterness is still there, but the other batches seem to have the flavors washed out or muddy, The decrease in quality seems only to show up in hoppy beers, though my belgium triple is not a good as I recall, and my saison did not seem to be affected. Problems started when I swapped kegerators. maybe, but I did not change any of the air lines, only the manifold. How can O2 get into a pressurized system? If there were leaks over a 2 month period would I not see a decrease in my CO2 tank? I cleaned the kegs - oxyclean and star san, cleaned the lines with line cleaner -
Do you purge the keg of O2 before you fill, and purge the headspace once full? If you really want to eliminate O2 in the process, fill the keg with sanitizer, push it out with CO2 and it will be full of Co2. Then fill through the liquid out tube, releasing the CO2 with the PRV, or put a tube on a gas in QD with the other end in a jar of sanitizer. That will take care of O2 in the keg if that is the problem.
hops are stored in the freezer - in sealed bags, but 6 months maybe. would the age cause a rapid decrease in flavor or would old hops just not develop flavor?
Sounds like a textbook case of oxidation. See hopfenunmaltz's post for a solution. Or at least purge with blasts of high CO2 pressure.
I forgot to ask if you dry hopped these beers? If you dry hopped the beers you can introduce oxygen from the process of DH'ing as well as oxidized hops if they are really old. I agree with the others, sounds like oxidation to me as well. Just need to narrow down where it came from. When you said you 'naturally forced carbed' did you force carb with CO2? or prime with sugar to condition? If you forced with CO2 then you should have purged the kegs. If you primed with sugar than purging isn't as necessary but is good practice, especially if the keg is not full.
yes, I purge my kegs, multiple times, but yes, it has to be oxidation issues. I do dry hop some beers, others not but they all end up ruined after a week in the keg. The citra pale keg did not hold pressure. I disconnected it this am and by this afternoon the keg was not pressurized. But, it is at all possible to introduce air into the system if CO2 in constantly being pushed into the kegs? It can't pull any in while flowing can it? Would it not seep out when no gas is moving? I am going to have to check all the keg connections, bummer
Partial pressure will push O2 into a bottle of beer through the cap seal, which is why Sierra Nevada went to pry off caps with a better liner. It will happen to a keg if not sealed, and most will need positive pressure to seal the lid.
"I cleaned the kegs - oxyclean and star san, cleaned the lines with line cleaner" Can you amplify on that procedure?
Hops stored in the freezer should not be the issue. I've got hops now that are over a year old, stored in the freezer, I have noticed no such loss of flavor or aroma. Of course you should keep them purged and tightly sealed, minimize exposure time to the air when weighing, and try to rotate stock and not leave any one bag open too long, but the rumors of hops turning to dog-doo when kept properly stored and frozen are likely over-stated.
Describe your keg co2 flushing procedure. Perhaps it's inadequate? Describe your kegging procedure. Is it a closed transfer or are you just siphoning the beer out of a fermenter and into a keg with no lid on it at first? Also describe your procedure for flushing the head space after you fill the keg. What psi do you use to purge the head space initially before force carbonating? If you purge the head space with too high of a psi, you can actually force any o2 in the keg into the beer. I'd also question your keg lid seal, but if it wasn't sealed properly you'd be draining your co2 tank when you leave the gas on it in the kegerator....
Unless the surface area is changing radically (splashing) due to the CO2 pressure, I don't see how this would happen, as compared with lower pressure. The path of least resistance for the O2 is to be pushed out of the keg. Looking at all the gas laws, I don't see any that would cause high CO2 purge pressure to drive O2 into solution. Am I missing something?
I'm talking about when the keg lid is on. Say the keg wasn't adequately co2 flushed to begin with, and/or an open transfer was done..... Presumably that head space could be filled with o2 and once the keg lid is put on, that o2 presumably could be forced into the beer if you either direct carb right away w/o flushing the head space first, or if you try to flush the head space with too high of a psi. At least that's what I was always told to worry about by some other homebrewers. So I flush the head space with 2-3psi first several times, then crank up to about 20psi and flush once or twice to ensure a good keg lid seal, then set to my carbing psi and let it carb.
Thanks for all the ideas, lots to think about. As I mentioned, this started when I changed kegerators, moving my stuff from one freezer to a refer. But a bad keg could also be a problem. Keg purge, same as always, purge at 20psi, let sit for a very short time and open up the release valve. Do this 4-5 times, and finish with a 2-3 second purge with the release valve open, Spent sometime last night with a friend discussing the problem, and he mentioned that due to different amounts of beer in kegs he sometimes gets changes in pressure causing beer to move backup the air hose. I too have had problems with changing carb levels in some of my kegs, occasionally, We then discussed this idea and even if beer was not moving, gas could. If one key was bad -- maybe a less than perfect seal -- and the pressure is lower than the other kegs maybe gas could move, but, with a bad seal I would loose CO2 out of my keg, and it never really goes down…. 20# keg, and its always open,,,, going to tear it all down - dump the beer- get new gas and liquid lines, install those secondary pressure regulators, redo all fittings, and start bottling my next few batches…….
No I have not ever purge the keg, do you seal the cap and fill it with co2 and then remove the cap and siphon? peter
You can either seal the cap on your already sanitized keg, fill it with co2 for a short while, pull the release valve, and repeat process 3-5 times.... OR You can fill the entire keg with sanitizer solution (diluted as per instructions), then hook co2 up to the gas post and hook a quick disconnect with a hose on it to the liquid post, turn the gas on and push all of the starsan out through the liquid post / quick disconnect / hose, and back into a bucket. That will both sanitize and flush all of the o2 out of your keg at the same time. The idea behind option A is that the co2 is heavier than o2, so it settles to the bottom of the keg and the o2 rises. When you pull the release valve, a mixture of the co2 and o2 comes out. After repeating process a few times, all of the o2 is out. The idea behind option B is that filling the keg with sanitizer replaces the o2 in the keg with water and sanitizer. Then using the gas to push that liquid out of the sealed keg replaces the liquid with co2. What kind of fermenter doe you use? Glass carboy? Bottling bucket? If you use glass carboys, you should research doing a "sealed transfer" for your hoppy beers. It allows you to push the beer out of the carboy with a very low pressure of co2 gas (4 psi or less) and into a sealed keg through the liquid post.
just to follow up on this situation. I am embarrassed and should keep my mouth shut but I hope others will not over look what should have been very obvious. The mold and slime in the faucet was beyond…, all three taps. Just cleaning the lines does not clean out the trapped debris when the keg blows or when it first gets going. Thanks for the suggestions, I am going to put on my big boy pants and clean up after my self.
