Off flavor, I think oxydation

This is the third beer in a row that has developed a bad taste after about two months in the keg. I wash and sanitize everything like crazy. I purge my kegs before filling. I feel it could be oxidation or off flavors from autolysis. Here are two things think I do that I believe could cause this. I am going to correct these on my next beer but would like opinions as to whether these things could cause my issue.

I use a pump to transfer the wort from the lauter tun to the kettle. During this process I have a fitting that I noticed is not air tight. This allows a steady stream of decent size air bubbles to enter the transfer hose and into the bottom of the wort in the kettle. I would assume this could cause the flavor issue (hot side aeration), but the beer tastes great for about 45 days, then begins to exhibit the off flavor. If this is the issue shouldn’t it taste bad right away?

I don’t use a secondary. I ferment in a converted freezer. I usually ferment 7 days at the cool end of the yeasts range, then I increase the temp to the upper end of the yeast range for seven days, and then crash it to 32 for 7 days before transferring into kegs and force carbonate. Is it possible that when I crash temp drops below 32 and freezes the yeast and rupture the yeast cells?


Any thoughts would be apriciated.

Can you describe the off flavor?

Not to start an argument haha but from what I have read on Hot side aeration is 50% of people believe it and the other half not so much. And once again I could be wrong here please correct me if so but when transferring to the kettle any oxygen induced should't cause an issue because even at the time of transferring to the primary we want to create a ton of oxygen for healthy yeast production. So the oxygen is not an issue in my book so it comes down to the Hot side aeration, or something else you might possibly be overlooking. Can you tell us what the off flavor tastes like to your best ability?

Years ago, I tracked an off flavour down to not my process but my kegs. I thought running hot oxyclean thru the lines and taps would be good but nooooooooo. Kegs posts need to be removed and taps need to be dismantled.
My off flavour gave a taste you might find in the bottom corner of an old closet.
When cleaning the kegs, I found the most gunk in the gas "in" post. After cleaning, kegs, lines, taps my problem was gone.

has the color changed slightly when they start to have this off-flavor? you are waiting quite some time, so if we were really affected by HSA on the homebrew scale, it would need quite a bit of time before the off-flavor started presenting itself, but i'm unsure on that timeline. i'm also on the side of the debate that believes that HSA isn't a big thing on our scale.

http://brulosophy.com/2014/11/18/is-hot-side-aeration-fact-or-fiction-exbeeriment-results/

I also don't believe that you could be killing off the yeast with your process. if you were doing that, the off-flavor would be presenting itself right away. Also, the freezing temp of beer is generally at least a couple degrees lower than 32. so if you have your temp controller set to 32, then you should be fine even if it swings a bit below that. But that's also why when I crash, I measure the chamber temperature and not the beer temperature, in order to avoid huge swings.

I could agree with the keg being dirty idea, except that, as you say, the off-flavor isn't presenting itself for quite some time.

I think we need a description of the bad taste before we can really help diagnose further.

It does sound like something that's in the minority, compared to the yeast remaining in suspension. Like my kottbusser & Irish red that's been in bottles a couple months. I've gotten some gushers, mainly from the red, after a couple months in boxes before fridge time. Even after a week, some bottles gushed.
Having said that, I began to notice those gusher bottles had a bit more trub & yeast at the bottom. After a couple months time, that layer of gunk must either be autolizing, or creating nucleation points to cause them to do so.
So maybe some settlings in your kegs are having the same effect over time?

Well Brick haus, you dont have to worry about starting an argument with me... I lack the experiance.

I completely disemble my kegs and posts, and quick connects, hell I even take the o-rings off the poppetts in the posts. I completely dissasemble my faucetts (remove all orings), scrub my beer lines with a line brush, i insure the kegs are clean, including top, conection holes, and pressure relief. I am a a cleaning/sanitation (starsan)nut. One thing I dont have is check valves in my co2 lines. I do clean and sanitize them the same way I do everything else.

joshesmusica- the beer does get alot clearer, but the srm is basicall the same. The problem showes up at about the two month mark. So if the yeast cells were damaged the taste would show up right away. That makes sense.

unionrdr- It seems that all of my beers are cloudy, I need to pay attention next time I clean a keg and note how much trub is in the bottom.

I have palmers how to brew book and read it cover to cover several time. I really cant match the taste to any symptoms in his book. The smell of the beer is good.

I just retasted it and thought for a second maybe butterscotch. I even chewed up a piece of cardboard. It didnt seem to taste like that. Heck... I just dont have the pallet the pallet to tell. I know it tastes bad. Kinda a wierd thing, the beer I tasted tonight tastes alot better than it did last time. Whats up with that?

I may have to bottle up a sample and take to my local brew club meeting and get some opinions?

I get my co2 bottles filled at a welding supply house, maybe somthing there?

I as well get my co2 from a local welding shop, Not saying that could not be the issue but for me I have never had an issue here.

What about water? What type of water are you using?

Hey. I wasn't trying to start an argument...
Doesn't sound like oxidation. Sounds like sanitation practices are sound. DMS? You don't cover your kettle during boil do you? I also get my co2 from the welding shop. No issues here.

I'd also wonder about the water source. If you've got chlorine/chloramine in the water you're not dealing with, that can be an issue. I've found chlorophenols to present themselves pretty rapidly though, so that may not be the problem.

We really do need a description of the off-flavor to help.

Soapy? Metallic? Does it show up in the aroma or just the flavor? Mouthfeel (harshness, astringency, slickness, etc)? It's it vegetal, spicy, medicinal? Lots off off-flavors can present in a lot of different ways, so there's only so much we can do.

Honestly, I think bringing to a local homebrew club (especially if there's some experienced BJCP judges) is a good bet.

I dont cover my kettle until flameout. At that time I cover and circulate through my counter flow chiller (with no cooling water going through it) to sanitize. Then whirlpool for 15, let it settle for 15, then transfer to fermenter. I also use a O2 stone to add oxygen, then pitch yeast. Maybe boils longer? does dms show up right away?

I use local tap water filtered through one of those whole house charcoal filters. I have ran probly 5 fifteen gallon batches through it. Maybe its lost its lost its effectivness?

We have a meeting tomorrow night. I will bottle sum up. It just wears on me. I work so hard to make good beer and then to have it slowely turn bad is almost more than I can stand

I will report what they say.

+1 for water. crappy water plagued me for years, and a charcoal filter may not do you any good as it never helped me at all. Simple test: buy bottled spring water for your next batch, do everything else the same, see if that fixes it. If it does then look into a water report and fixing your water chemistry.

frontiercdk said:

I just retasted it and thought for a second maybe butterscotch.

Click to expand...

Buttery or butterscotch sounds like diacetyl. If from fermentation I would think that would show up right away, if develops later maybe pediococcus?

I think the city will provide a water report upon request. I will look into that tomorrow.

What is pediococcus?

frontiercdk said:

I think the city will provide a water report upon request. I will look into that tomorrow.

What is pediococcus?

Click to expand...

Lactic acid producing bacteria. Also produces a bunch of diacetyl in addition to lactic acid. If your beer is developing unwanted sourness and a butter character, that's quite possibly the culprit.

You say you don't have check valves in your co2 lines, have you ever seen any beer in a co2 line?
If so was the regulator dismantled and cleaned?

I chased oxidation after kegging for several batches. It was intermittant and varied by individual kegs. It presented after two weeks in the keg as loss of hop aroma and then hop taste leaving just a nasty bitterness. The beer (lighter styles) would get noticeably darker as time progressed.

I found that some of my kegs had shorter dip tubes than others and I was leaving residual sanitizer in the kegs. Using co2 to push the sanitizer out was not adequate.

Now, I still use co2 to push the sanitizer out but I turn the keg upside after liquid stops coming out. The residual sanitizer collects in the lid that can be quickly discarded.

Thank you guys for the ideas. My hebrew meeting is tomorrow. I thought is was this evening. I will let yall kow what flavor they taste after the meeting.

I attended my brew club meeting last night and several senior members gave the beer a taste.

They all agreed oxidation, and slight diacetyl. Mainly oxidation (stale) with a slight diacetyl (butterschotch) thown in. They suggested reducing oxygen eposure to the hot wort and a longer diacetyl rest.

The air leak I have from my lauter tun into my boil kettle is massive and does create alot of exposure. It usually forms about a 10" 4" pyrimid shaped foam head on the wort before I get the lauter tun drained.

Not all of them noticed butterscotch flavor, but I will add a three day diacetyl rest next time.

Anyway... thanks for the ideas. I will post the results of my next beer.

Update,

I corrected the several air issues I had with my system and switched to WLP001. I have two beers that are over two months old with no issues. I assume the introduction of all that air was the culprit.