I have 2 beers on tap which were aged 3 and 5 months respectively. ( an imperial amber lager 8% and an Irish red ale 5.3%). Both tasted very good when I tapped them and now after sharing and enjoying these great beers, 2 weeks later they both taste different. I know there is a lot more head space in the kegs but what could cause these new flavors? The kegs are only half empty. Bad gas? bad tubing?
Can you describe the flavors you’re tasting?
Do you clean your beer lines every week?
I change out my lines every year and run fresh water though the lines after each keg is finished. Sometimes I’ll use line cleaner. I only drink 100 gal per year. These lines are only 6 months old.
The taste is almost like a grain alcohol taste with a hint of plastic but the whole flavor base is changed. The hoppiness is diminished and the deep flavor profile is diminished with an added after flavor.
But for weeks the beer tastes great, when its half gone is when I get the bad flavors.
I would start with cleaning the lines. You say they are only 6 months old, but the good beer bars around here clean their lines every 2 weeks at a minimum.
How did you age them? I’m thinking that if you aged them in a carboy and then racked to corny you could have introduced some o2 which would cause flavor degradation.
I go from primary directly to the corny and I release the pressure a few times to help purge the o2. I don’t know of any other way to do it.
Beer bars might pour hundreds of gallons per week. It’s not practical to use line cleaner before the 5 gal keg is even finished.
you can fill the empty keg with sanitizer right to the very brim, seal it up and force that sanitizer out with co2. this should remove almost all the o2 so when you wrack from primary into the keg there is no o2 contact to speak up.
I like to run cleaner through my cobra taps every time a keg empties. since the keg already has cleaner in it I just run it off through the tap. I imagine you could do the same thing for regular faucets no?
for the short term you could pour the first ounce or so into a slop bucket which should get rid of any grossness in the lines from the beer sitting for x days.
If it’s the whole second half of the keg it could be the keg itself. It doesn’t sound from the OP like its just the beer in the lines.
Have you replaced all the seals on the kegs?
There was also another thread where someone had bad beer lines. The tubing was not rated for liquid and was causing a nasty plastic flavor.
Not on a regular basis, no, but when your beer is tasting funny? Absolutely clean the lines. While you have the keg disconnected, hook up a cobra faucet and try it that way, see if the off flavor is in the keg.
If it is, it’s entirely possible that the off flavor started in the lines and has migrated to the keg.
I definitely do NOT clean my beers lines every week but I have had occasions where every bear on tap developed an odd, just sort of off flavor. The first time, I started trying to find my process problems and ended up cleaning the lines to see what would happen. After the cleaning the odd flavor went away. It won’t fix every problem but it does sometimes fix this problem. 8^)
Paul
You say that you have recently replaced the beer lines, but have you ever replaced the gas lines? Even with a backflow-prevention valve on the regulator or manifold, it is still possible for a small amount of beer to ‘burp’ back into the gas line if you hook it up under pressure and it is quite full.
I had a series of kegs go sour on me, and solved the issue by replacing my gas lines. It couldn’t hurt…
FYI per industry standard purging a vessel is as easy as filling it to 5 psi and releasing the pressure twice. You should do that to your corny kegs every time before you fill.
If a pressure line has had beer “burped” back into the tube, can this tube cause an infection in fermented beers down the road ?
I would think so! if it is not cleaned out there is beer in there inviting infection and once that infection has taken hold it’s being blown directly back into the keg.
Hmmm. . . another thread got me thinking. What is the temp/pressure on the kegs? Pushing with too much CO2 is fine short term, but long term it leads to over carbonation. Over carbonation can kill aromas and if there is enough carbonic acid there will be a common off flavor in the beers.
Good catch. Especially with hoppy beers.