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Purple beer, purple gunk

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oooFishy

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A while ago I decided to primary in a couple of 5 gal sanitized + purged cornies. I fitted airlocks for the primary fermentation with a tight wrap of electrical and duct tape to make a seal, and once bubbling subsided I refitted the pressure release valves. Throughout the rest of fermentation I released pressure from the kegs from the valves, either due to continued fermentation or dissolved c02. They sat in the kegs for about a month. I then transferred to purged + sanitized buckets. I noticed the beer had gotten much darker. When I went to carbonate I realized that the beer had turned a winey, purple color. A thick slurry of purple gunk was left behind. I took a sample of the slurry and spun it down in a centrifuge to find a small white pellet among the purple gunk, indicated that the yeast itself was not purple.

I'm assuming I got a contamination from the kegs....It's strange that the exact same thing happened to both of my beers. I'm thinking that by releasing pressure all the time I let nasties get in the beer. It tastes slightly vinegary...

Any ideas?
 

Germey

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in relatively low concentrations, Iodophor will turn proteins purple. Any chance you had some iodophor solution in the kegs?
 

TreAdidas

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OK I am going to spin this back up because I think the same thing is happening to me.

Situation is I keg a beer and all is going splendidly. Keg carbs up in a week or so (set it and forget it style), beer pours fine we are happy. Then I let the keg sit for a couple of weeks and all of a sudden I go to pull a pint and the beer has gone from the normal golden color one would expect from a primarily 2-row base to some purplish/brownish murky poo water (see pic).

But the plot thickens…. this has happened to me on TWO separate brews. Both on the same keg. And these are the only two beers I have put in this keg as I recently expanded my setup. Further, when I dumped the first batch this happened to, there was a thick goop that coated the keg walls. Sounds very similar to the OP's situation. Is there any reason that a keg would somehow interact with the beer to cause this? Is there some off chance that this keg (which I bought used) was used for some odd purposes in its previous life that would render it useless for beer?

Now before you go asking, I am absolutely crazy about sanitation. I am keeping Five Star in business with all of the PBW and Star San I buy. Further, I also redid all of the o-rings on this keg.

In any case, this keg is going on an indefinite timeout until I can figure this out.

Any ideas?

IMG_0319.jpg
 

TreAdidas

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did you taste it? does it smell wierd?
Yes and yes.

Smell = bad fruit, vinegar, bad wine (joint commentary from my wife and I).
Taste = A very off-putting vinegar. Almost medicinal in nature.

FYI - The recipe I brewed is Kelsey McNair's Hop-Fu! as it appeared in Zymurgy a couple of months ago.
 

OleGoatBrewing

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Have you made any adjustments to your brew session? I was tweaking my mash process and got a cloudy beer which normally is pretty clean.
 

TreAdidas

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Have you made any adjustments to your brew session? I was tweaking my mash process and got a cloudy beer which normally is pretty clean.
Can't say I have.

What's weird is that everything looks and tastes GREAT until it sits in the keg for a few weeks. Then it all goes to hell.
 

tomlerner

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I have this exact thing happening to me now. Made 5 gallons of a Belgian Tripel and split two gallons off to a mini-keg I bought on CraigsList. For the two gallons, I added some tequila-soaked oak chips to it.

The non-oaked Tripel went into kegging and I carbed it right up. It tastes and looks awesome. The oaked tripel went into the mini-keg but I only purged the Oxygen and left a CO2 blanket on top. I left it like that for about a month, replacing the CO2 blanket a couple of times. I just poured it tonight and it's that exact purple color you showed in that picture.

The beer, however, still tastes great. I detect a slight fruity tartness to it that shouldn't be there, but it's actually really good. I could probably call it a Boysenberry Tripel and everyone would love it. Or, this will progress slowly into salad dressing....

It's my first batch that I suspect has been infected. Anyone figure out this purple demon?
 

helterscelter

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I have this exact thing happening to me now. Made 5 gallons of a Belgian Tripel and split two gallons off to a mini-keg I bought on CraigsList. For the two gallons, I added some tequila-soaked oak chips to it.
Subbed. Interesting. If it tastes OK, could the color be coming from the oak chips? The original op didn't mention any oaking or other additives. I wonder if you are having a different issue with similar (color) symptoms?
 

tomlerner

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I hope so Helter. I'm entering the regular Tripel in a homebrew comp this weekend and was hoping to enter this tequila-oaked version as well to stand next to it. No way will I try that now until I see where this is going.

I've only used oak chips in a stout before so I have no visual experience to guide me on how much the color can change from them. I could see some honey brown color coming from them but not purple/pink.
 

coho3

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OK I am going to spin this back up because I think the same thing is happening to me.

Situation is I keg a beer and all is going splendidly. Keg carbs up in a week or so (set it and forget it style), beer pours fine we are happy. Then I let the keg sit for a couple of weeks and all of a sudden I go to pull a pint and the beer has gone from the normal golden color one would expect from a primarily 2-row base to some purplish/brownish murky poo water (see pic).

But the plot thickens. this has happened to me on TWO separate brews. Both on the same keg. And these are the only two beers I have put in this keg as I recently expanded my setup. Further, when I dumped the first batch this happened to, there was a thick goop that coated the keg walls. Sounds very similar to the OP's situation. Is there any reason that a keg would somehow interact with the beer to cause this? Is there some off chance that this keg (which I bought used) was used for some odd purposes in its previous life that would render it useless for beer?

Now before you go asking, I am absolutely crazy about sanitation. I am keeping Five Star in business with all of the PBW and Star San I buy. Further, I also redid all of the o-rings on this keg.

In any case, this keg is going on an indefinite timeout until I can figure this out.

Any ideas?

View attachment 239574
Did you ever find out what was causing this to happen? I am now on my fourth batch of this phenomenon occurring and it is almost kicking me out of homebrewing.
 

jasonvt

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That is caused by oxygen. It can take a while to show up after the oxygen exposure. Try limiting the amount of racking and purge any vessels with CO2.
 

Dgallo

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@jasonvt is 100% correct, its extreme oxidation. Review proper cold side LODO processes. If you brew hoppy beers you may want to follow the process that are targeted for NEIPAS. they are the most susceptible to oxidation and us hopheads go to extreme measures to minimize o2 pick up.
 
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