Keg was carbonated 2 wks, then went flat? (pics)

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spaceyaquarius

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I kegged a Shock Top Clone March 30th, 2013, it's been on 10 PSI at 37 F for 2 weeks now. Yesterday I tried it and it was perfect. Perfect head, highly carbonated with lots of bubbles rising to the surface down to the last drink.



8 glasses later, the head all disappeared and there was an acidic taste and it was undrinkable.



Now today, the beer it back to where it was and tastes ok again.

Maybe it needed more than 2 weeks to carbonate fully and pouring 8 glasses took CO2 out of the beer? Then letting it set overnight allowed it to carbonate again?

That's one theory, but now that I think about it, maybe there's just a very slow leak that is undetectable with starsan spray?
 
You sure you weren't just drunk from 8 glasses of beer ;)? Kegs don't de-carb that fast. Could have been something in the glass that did it? I see you have two different glasses. The acidity is strange, which makes me think it was something in the glass, not the beer, soap perhaps? How is the beer now?
 
The 1st glass today was good - ok taste and an inch of head.

Then the 2nd glass was back to being terrible, no head, but it does have CO2 bubbles rising to the surface at the right amount. I used a new glass.
 
You sure you weren't just drunk from 8 glasses of beer ;)? Kegs don't de-carb that fast. Could have been something in the glass that did it? I see you have two different glasses. The acidity is strange, which makes me think it was something in the glass, not the beer, soap perhaps? How is the beer now?

You may be right. The 1st glass today had CO2 bubbles but no head and a bad acid taste. The 2nd glass (new glass) has tons of head and CO2 bubbles and now the taste is much less acidic, but the nice tasting flavor I had is gone.

I'm still not sure what is going on. I did vent the oxygen out of the keg before sealing it.
 
I guess the other thing could have been some sort of beer line cleaner that was in the lines or tap, but that wouldn't have lasted to another day. I'm trying to think of all the places good beer could go wrong on the way from keg to glass. Diptube, connector, beer line, shank, faucet, glass. Start checking them off and figure out where it's coming from. The beer couldn't vary that much from pour to pour.
 
I have new beer lines and haven't cleaned them yet, diptube has never been cleaned, connectors have a new o-rings on them, faucet is just the cheap picnic keg plastic one that comes with the starter kit.

OK, I was thinking about the fact that I used SanStar in the keg and did not let it drip dry. I was in a hurry and just rinsed it out with the kitchen sink sprayer. I did use the right concentration, but there may have been alot of SanStar left in the keg. I wonder if it would kill head and change the taste while allowing the carbonation level to be normal? Just a theory.

I still believe the flavor has been ruined from yesterday to today. When the beer was not ready yet (I was checking it once a day) I did see a lot of soapy looking bubbles in the glass. Can SanStar ruin flavor? Even so, why would the flavor be good one day and bad the next? I am new to home brewing, so who knows what I've done wrong.
 
If you're worried about StarSan, pull the keg out to room temps for a few days.

I heard at one point that yeast can metabolize leftover StarSan. Can't remember the reference though, sorry.
 
I was looking around, and it could be that my 3/16" beer lines are only 4.75 feet long. But would that explain how 8 glasses are perfect, and then I get flat tasting beer afterwards?

I just ordered 10 foot lines.
 
Warm lines, shanks and faucets cause more foaming until they get cold.

But that wouldn't explain your acidic taste. Are you serving at 10 psi or just carbing at that?
 
Warm lines, shanks and faucets cause more foaming until they get cold.

But that wouldn't explain your acidic taste. Are you serving at 10 psi or just carbing at that?

I carbed and served at 10 PSI. Was just trying to keep it simple bc I screwed the last keg up. I think it's weird that taste would change from one day to the next.
 
Could it be your tasting the stale beer that's been sitting in the beer line? Might explain why the second pour was better tasting.
 
Lets start with the basics.

Scrub the inside of the faucet. Maybe you have built up some lacto. Swap the line with another if you have a spare.

Check for leaks everywhere between the tank and the faucet. You could be drawing O2 in somewhere.
 
Lets start with the basics.

Scrub the inside of the faucet. Maybe you have built up some lacto. Swap the line with another if you have a spare.

Check for leaks everywhere between the tank and the faucet. You could be drawing O2 in somewhere.

Shouldn't be the beer lines, since they're only 4.75 feet long, but I will check that. The O2 sounds more likely. I've heard people saying on here that O2 makes an acidic taste in the beer? There could definitely be a slow leak somewhere bc the carbonation level in the beer is not consistent. It has been on 10 PSI for 16 days, so it should be done carbing. I'll pressurize the keg and put it in the bathtub after this keg is empty.
 
In the meantime, spray water on every seal and connection to check the keg for leaks.

I wouldn't say oxidized beer tastes acidic. I think it tastes like the smell of dried sweat, but most people consider it to have a wet cardboard taste, whatever that means.
 
In the meantime, spray water on every seal and connection to check the keg for leaks.

I wouldn't say oxidized beer tastes acidic. I think it tastes like the smell of dried sweat, but most people consider it to have a wet cardboard taste, whatever that means.

Yes, it's a little hard to describe the bad taste. It's kind of like a flat taste (while lots of bubbles still exist), and a bitter/acid aftertaste. A good belgian wheat beer leaves a nice citrus/complex taste on the tongue.
 
It may be because you didn't clean the dip tube...i had something similar with my first keg where I didn't scrub it out, just ran water through it. The first glass would be terrible - phenolic/metallic tasting. I took the beer oit assembly apart and recleaned everything Nd it stopped happening.

Did you take the poppits out to clean them? I'd suggest you de pressurize the keg and pull all the components off and clean them well with PBW and a brush, then rinse, starsan and reassemble. Don't forget to sanitize your hands too - I wear disposable vinyl gloves for this.

Cover the openings loosely with starsan sprayed aluminum foil while you're cleaning the parts.
 
It may be because you didn't clean the dip tube...i had something similar with my first keg where I didn't scrub it out, just ran water through it. The first glass would be terrible - phenolic/metallic tasting. I took the beer oit assembly apart and recleaned everything Nd it stopped happening.

Did you take the poppits out to clean them? I'd suggest you de pressurize the keg and pull all the components off and clean them well with PBW and a brush, then rinse, starsan and reassemble. Don't forget to sanitize your hands too - I wear disposable vinyl gloves for this.

Cover the openings loosely with starsan sprayed aluminum foil while you're cleaning the parts.

Well, I didn't clean the dip tube. I replaced the upper o-rings. I couldn't get the tube out last time I tried. I'll start over and clean out the tube. What is PBW?
 
Powdered Brewery Wash - It's a 5-star chemicals product. Works like a dream.

Star san would break down completely in the presence of anything with a pH of over 5. The phosphoric acid (main ingredient) is neutralized by sugars and the dodecylbenzene sulfonic acid will break down into various pretty innocuous compounds (some of which are yeast food) plus a sulfonated benzene ring, which is pretty much biologically inert.

That's above an beyond the fact that used to the manufacturer's directions, star-san has pretty much no flavor.
 
Yes, it's a little hard to describe the bad taste. It's kind of like a flat taste (while lots of bubbles still exist), and a bitter/acid aftertaste. A good belgian wheat beer leaves a nice citrus/complex taste on the tongue.

That's probably due to the short lines- the co2 being "knocked" out of suspension.

But I am a bit concerned about not breaking down the keg and cleaning it and sanitizing it. If the diptube doesn't come out, that probably means it's plastered to the post and gummed up with debris. That could be why there are some flavor issues.
 
That's probably due to the short lines- the co2 being "knocked" out of suspension.

But I am a bit concerned about not breaking down the keg and cleaning it and sanitizing it. If the diptube doesn't come out, that probably means it's plastered to the post and gummed up with debris. That could be why there are some flavor issues.

Yeah, I've got to clean it right. I put a wrench on it and hit it with a hammer and it wouldn't budge. This may be a stupid question, but would WD-40 on it help get it off there?
 
Yeah, I've got to clean it right. I put a wrench on it and hit it with a hammer and it wouldn't budge. This may be a stupid question, but would WD-40 on it help get it off there?

No, I don't think so because it's probably gunked up inside, not outside. Maybe the rubber o-ring has sort of melted/stuck (that happened to one of mine), or the post is full of crud. I got all of mine off, eventually, with some brute strength. (This is really funny, if you actually saw me in person! :D)

My "brute strength" also involved a mallet, a hammer, a deep socket, and lots of curse words. I think it was the old Army combo of "mother" and all the four letter words I knew that persuaded it to come off. :drunk:

But check with the manufacturer of your keg, to make sure you aren't going to damage it. I have a mix of challenger kegs, cornelius, and firestone kegs, and they are different but they all come off.
 
OK,it's a Cornelius keg. The homebrew shop here said it was reconditioned, but of course it was not. I'll probably buy a deep socket and use a socket wrench and mallet. The thing kept turning when I was trying to get it off. Maybe if I get someone to hold the keg it would help.

:fro:Thanks for the help.:fro: I think this is probably the source of the problem. Gunk on the inside and probably a slow leak as well.
 
****, I took the keg apart and the dip tube was completely clean. There was no gunk inside the ball locks or anywhere. I still don't know where the acidic taste came from.

Now I'm thinking it could have just been overcarbed, because the beer lines were 1/4" and only 4.75 feet long. So if the wrong lines pull CO2 out of the beer, then I'm checking for the right amount of bubbles before I drink it and then it gets overcarbed? Hmmmm. Still not sure.
 
spaceyaquarius said:
****, I took the keg apart and the dip tube was completely clean. There was no gunk inside the ball locks or anywhere. I still don't know where the acidic taste came from.

Now I'm thinking it could have just been overcarbed, because the beer lines were 1/4" and only 4.75 feet long. So if the wrong lines pull CO2 out of the beer, then I'm checking for the right amount of bubbles before I drink it and then it gets overcarbed? Hmmmm. Still not sure.

I think you have two issues going on. The line length and diameter does affect foaming.

When I had my issue I never saw anything obvious either but the problem went away. How does your first pull taste now?
 
I think you have two issues going on. The line length and diameter does affect foaming.

When I had my issue I never saw anything obvious either but the problem went away. How does your first pull taste now?

The foam problem doesn't bother me nearly as much as the fact that the beer tasted great for 8 glasses, and then worse as time went on.

The keg is now emptied (I drank it even though the aftertaste was pretty bad at the end). I cleaned and checked for leaks after it was empty.

Since it was clean and not leaking, the issue has to be the beer lines (inner diameter and/or length) causing the too much foam problem. And then the acidic taste is probably caused by the carbonation process not being done correctly. I don't know of any other way a beer could lose flavor and taste flat and have an aftertaste except for overcarbonation.

I just ordered 10 feet of 3/16" inner diameter lines.
 
Overcarbing making it taste flat? I think we're reaching a bit here.

Maybe you grew out of Shock Top?

No, overcarbing does make a beer flat. Weird, I know.

But what happens is the co2 is "knocked" out of solution on the way to the tap. That makes a big foamy head (or a whole glass of foam) that is comprised of co2. When the foam dies down, the underlying beer is lacking the co2 due to it coming out of the beer during dispensing (creating the foam). In that case, a flat tasting and feeling beer is indeed due to overcarbonation and serving with a line unable to handle that carb level (ie lines too short for that carbonation level).
 
But that wouldn't account for the taste issues would it? The fact it would change from the first pour and that it got worse over time...
 
No, overcarbing does make a beer flat. Weird, I know.

But what happens is the co2 is "knocked" out of solution on the way to the tap. That makes a big foamy head (or a whole glass of foam) that is comprised of co2. When the foam dies down, the underlying beer is lacking the co2 due to it coming out of the beer during dispensing (creating the foam). In that case, a flat tasting and feeling beer is indeed due to overcarbonation and serving with a line unable to handle that carb level (ie lines too short for that carbonation level).

That's a theory that seems to fit the facts. I know I said that the PSI was set at 10 PSI, but in reality, it was set at 10 PSI for 10 days (it was totally flat) and then for 2 days I jacked it up to 15 PSI, and then turned it back down to 10 PSI. I didn't shake or rock the keg.

Looking at the graph below from the sticky in the kegging forum, maybe the carbonation was traveling up like the green line, I turned it up to 15, causing a jump in the volumes of carbonation (red line), but the overcarbing didn't really kick in until the 9th glass? The 1st 8 glasses had perfect head (1 to 1.5 inches) and perfect carbonation and good taste. The 9th glass had tons of head (2.5-3 inches) and perfect carbonation. The 11th glass had tons of head (3-4 inches) and not enough bubbles.

The next morning the 1st glass tasted good again, but then the 2nd was flat and acidic tasting again and it never got better after that.

So if the beer lines were pulling carbonation out of the beer before it hits the glass, then by the time I thought the keg was ready for drinking, it was nearly overcarbed and then became overcarbed in the next few hours? I was also shooting for 3.0 carbonation (for a Belgian Wheat) but that may be a mistake. I should shoot for 2.0 until I can get this right.

That makes sense, since the keg was not leaking and the diptube and connections were all completely clean.


 
Even If you carbed it to 15 psi at 37F, that's only 2.9 vol. That's barely outside the realm of an American wheat, still way lower than a Euro wheat. Ill bet you're actually in the 2.7 vol range.
 
Well, something definitely went wrong. The wheat was not steeped above 160 F so it wasn't a tannis taste, there was no leak in the keg, the diptube and posts were not gunked up. It has to be a carbonation issue.

I guess there is a possibility that the gauge is not reading correctly. If it is giving a PSI reading that is lower than actual, then it could overcarb. Is is common for a CO2 gayge to not read correctly when inside a fridge?

This is my setup.

 
Now I really think that the CO2 gauge is not reading correctly. I have overcarbed 5 batches of kegged beer. Then when I bottle the same type of beer, brewed even on the same day, it has no acidic/bite aftertaste.

It is definitely an overcarbing problem (not the diptube or beer lines [new 10' 3/16" vinyl lines]).

My new overcarbed batch was set at 13 PSI for 3 weeks and got overcarbed. Has to be the gauge I believe. Will set the PSI to 7 or 8 PSI next time and see what happens.
 
spaceyaquarius said:
Now I really think that the CO2 gauge is not reading correctly. I have overcarbed 5 batches of kegged beer. Then when I bottle the same type of beer, brewed even on the same day, it has no acidic/bite aftertaste.

It is definitely an overcarbing problem (not the diptube or beer lines [new 10' 3/16" vinyl lines]).

My new overcarbed batch was set at 13 PSI for 3 weeks and got overcarbed. Has to be the gauge I believe. Will set the PSI to 7 or 8 PSI next time and see what happens.

Could very well be. You can bleed the pressure off and see how it is ... Unless those kegs are now empty?
 
Resolution:

Combination of a faulty gauge (which was reading lower than actual PSI), and impatience (the beer was also too young).

Replaced the gauge, and now I force carb for 3-4 weeks with the "set it and forget it" method instead of 1-2 weeks.

THANKS EVERYONE!!!
 
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