Devil bacteria in Corny kegs

[Aloha_Brew]

It has been over five months now since my kegging world turned upside down. I had moved and mistakenly left some residual beer in two of my Corny kegs, while a third one was empty. The ones with beer in them were kept for a few days at temperatures above 80 degrees inadvertently and led to the beer spoiling, turning into a vinegary mess that was undrinkable, even though they were sealed the whole time. I thoroughly cleaned them with some elbow grease (using dishwashing soap and a scrubbing sponge) and replaced all gaskets before StarSan was applied to both.

Two months later I brewed up a Scotch at about 8% and an Irish Red at about 4.5%. I tasted them before putting them in the keg and they tasted great. After two or three days in the kegs I started to drink the Irish Red and noticed a distinct difference, that had a similar vinegary taste mentioned before. The fridge it they were in was kept at 40 degrees. This didn't halt the infection from further destroying my beer until it again became undrinkable, to include little white flecks of something that were easily seen as I dispensed it and a slight opaque film on the top of the liquid when I opened the keg to sample from the top. I tasted the scotch and it had a fainter taste of the vinegar flavor, but remained somewhat drinkable.

Round 2. I purchased some PBW and brushes to fit into the keg's smaller tubes and cleaned the ever-living daylights out of it. I soaked all the parts in PBW over 24 hours in hot water, including the rubber poppet-valves and the dispensing hoses, and soaked everything in StarSan (even turning the kegs over halfway and draining a bit off to ensure everything was whetted). I brewed an Imperial IPA at 101 IBU and an Oktoberfest lager. I put the Oktoberfest in the keg I had used for the Irish Red and the IPA in the one that had the Scotch. I had left the IPA in the keg for about a week at room temperature to dry hop it and had the Oktoberfest lager in the other keg for about 4 weeks at 40 degrees.

I went to taste the Oktoberfest recently and noticed again that same vinegary taste. It is undrinkable. I had put some in a separate growler, so I know it's not the beer itself. The IPA also developed a slight vinegar taste but has remained somewhat drinkable so far. So, I'm just wanting some feedback to see if anyone has experienced similar things before and has beat these beasties into submission somehow. The only thing I haven't done so far is to attempt to sterilize with boiling water, bleach and water solution, or steam/ autoclave (to which I have no idea how to accomplish it even if I wasn't afraid it would render the attached rubber/ plastic completely useless).

I believe this is an acetobacter infection. This is due to the symptoms (vinegar flavor that develops into an undrinkable solution and white flakes) and the fact that I have seen a few dead fruit flies, that are known carriers, magically appear in the same freezer after a few days of not opening it. However, I cannot believe it is remaining and active through an airborne path, as that same logic would indicate that anything in that freezer should also be affected. The beer from the fermenters I have placed in there and my third keg remain unaffected by this though. So, the only conclusion I can come up with is that my cleaning methods are not good enough, even though all other resources state that it should be. I just want to stop creating vinegar and go back to making beer and am almost at the point of throwing these two kegs out.

I do plan on making a Flander's Red and a lambic here soon, but with these past ones turning into almost pure vinegar I sincerely doubt that these would anything but ruinous to my prolonged efforts. I know enough to recognize that sour might be good but vinegar is very bad. Yet this bastard infection continues to survive with higher alcohol levels and high IBUs and low temperatures. Early on even, after I had initially applied StarSan both times and let the kegs sit, I also detected a slight vinegary scent even with the sanitizing agent still obviously present. That second round I sanitized it again with StarSan and didn't smell the vinegar scent after another couple days of waiting, so I thought I'd beaten it. I realize this is pretty drawn out and apologize for the rant! I'll go back to drinking my vinegar beer now...

 

[patthebrewer]

Soak in either PBW (as before) or my favorite, B-brite, also hot for 24 to 48 hours filled up to over flowing out of the post holes(drop dip tubes in too). Remove posts and discard ALL rubber gaskets, including poppetsvalves. After soaking and flushing star-san COMPLETELY, repace new gaskets(orings) and poppets, Leave the bubbles, do no rinse star san of surfaces put posts, and gaskets on wet, and gas up. Store under gas.....can't imagine anything surviving that.


Oh...and Aloha....sorry just had to say that. Living here in the northeast US with a Blizzard bearing down on us, and 30 degree temps, has me really wishing I live where you live.

 

[-MG-]

This has me worried about a 'taste' I've seen from a few of my kegs (haven't seen if its the same one). Few of my beers had a similar taste to it no matter the style, but I think that could be something else.

But this is pretty scary. I wonder if you could do an acid rinse of some sort on a corny to get EVERYTHING out.

 

[midfielder5]

I don't think you can safely bleach stainless steel.
Try 1 cup vinegar to 5 gallons -- in addition to what the guy above me said re replacing all plastic.
Soak overnight, rinse with super hot (boiling even) water. I would then try a second round of a different cleaner like oxiclean.

I would also replace, not clean, all keg lines.

Sucks to hear about this!

 

[Misplaced_Canuck]

This is due to the symptoms (vinegar flavor that develops into an undrinkable solution and white flakes) and the fact that I have seen a few dead fruit flies, that are known carriers, magically appear in the same freezer after a few days of not opening it. However, I cannot believe it is remaining and active through an airborne path, as that same logic would indicate that anything in that freezer should also be affected. The beer from the fermenters I have placed in there and my third keg remain unaffected by this though.

I have a hunch that your keezer itself is infected. You're brewing the beer, and it's fine, as you're not fermenting inside the keezer (at least that's what I presume). You then put the fermenter in the keezer to cold-age/lager, and the exterior of the fermenter is picking up acetobacter while it's in there. As you rack from the now-tainted fermenter (on the exterior), your hands or other instruments are touching that tainted fermenter, and infecting the beer as it goes in the keg.

I would recommend the following:

Get a spray bottle of Lysol cleaner with bleach (or the walmart brand with bleach). Clean the inside of your keezer completely, and let it dry out and aerate for a few days. Don't forget to clean the inside of the lid, too.

Also, when it comes time to rack, spray down the outside of the fermenter with the same lysol cleaner, prior to transferring the beer. This should prevent any bugs from tagging along from the outside of the fermenter to the keg. Don't forget to clean the underside of the fermenter too. You may consider using a shallow pan with a bleach water mixture, that way you don't have to put the fermenter on its side to clean the underside.

Also, as others have said, take apart all kegs/hoses/taps and clean with PBW or oxy-clean, and sanitize with Starsan.

MC

 

[TopherM]

left some residual beer in two of my Corny kegs, while a third one was empty. The ones with beer in them were kept for a few days at temperatures above 80 degrees inadvertently and led to the beer spoiling, turning into a vinegary mess that was undrinkable, even though they were sealed the whole time.

It sounds like you had your infection before you took the beer out of the fridge temps, the fridge temps were just keeping the infection in check.

Simply leaving a sealed, purged keg of beer at temps above 80 for a few days will NOT spoil the beer. I routinely rack beers from primary to a corny keg and let them sit for several weeks, like a month or two at room temps around 74-76. As long as they are properly sealed and purged, that's the same idea as a secondary fermentation, and would not lead to spoilage for several months without other factors at play.

You had the infection before that point.

Definitely soak in bleach for 24-48 hours, then soak in hotwater baking soda solution for 24 hours to get rid of the bleach smell, then soak in hotwater PBW/OxyClean solution for another 24 hours, then soak in hotwater StarSan solution for another 24 hours. Do all of this with the keg posts, tubes, and lid at the bottom of the keg to soak. Replace all of the O-rings in the keg posts and lid, as well as all of your kegorator lines.

That'll do the trick! That's how I clean and sanatize the kegs I use bacteria and wild yeast in.

 

[two_hearted]

I've had similar issues with a diacetyl off flavor and my kegs. I've swapped out almost everything plastic and not I am trying new kegs, tubing, faucets. Fortunately the off flavor isn't terrible and the beer is drinkable.

Check you bev tubing, shank and faucet. Really disassemble and scrub them clean. Use form BLC on your tubing.

 

[processhead]

Maybe you have already done this, but don't overlook your beer lines, quick connects, and all the other dispensing system hardware.

The infection could have migrated outside of the kegs.

You could be getting a reinfection through these parts even though it sounds like you have done a good job of cleaning/sanitizing the kegs themselves.

 

[JRems]

I would try a bleach solution for the kegs. While it will oxidize stainless, it's not a problem if left for only a few hours. Just don't leave bleach in stainless for days. After you rinse the bleack out well , re passivate and sanitize with a star San solution. I would throw away all rubber, and replace the lines. Them take apart your disconnects as well as shanks and faucets and clean then boil all parts.

 

[Aloha_Brew]

Soak in either PBW (as before) or my favorite, B-brite, also hot for 24 to 48 hours filled up to over flowing out of the post holes(drop dip tubes in too). Remove posts and discard ALL rubber gaskets, including poppetsvalves. After soaking and flushing star-san COMPLETELY, repace new gaskets(orings) and poppets, Leave the bubbles, do no rinse star san of surfaces put posts, and gaskets on wet, and gas up. Store under gas.....can't imagine anything surviving that.


Oh...and Aloha....sorry just had to say that. Living here in the northeast US with a Blizzard bearing down on us, and 30 degree temps, has me really wishing I live where you live.

I did the PBW with hot water from the faucet for 24 hours and heard that any more than that is not really any more beneficial compared to the possibility of developing beer stones. I did everything else you've said except to fill it with CO2 after StarSan or replace the poppets, and I don't rinse the StarSan, but I've pressurized the keg with beer in it and it still gets noticably worse over time...so I don't think that would make much of a difference.

Stay warm inside and drink beer man! Best way to weather out a storm.

 

[Aloha_Brew]

This has me worried about a 'taste' I've seen from a few of my kegs (haven't seen if its the same one). Few of my beers had a similar taste to it no matter the style, but I think that could be something else.

But this is pretty scary. I wonder if you could do an acid rinse of some sort on a corny to get EVERYTHING out.

I've seen various discussions about infections as I've researched this. There is something called "house taste" which develops among your personal palette, to the point that local bacteria and wild yeast might get introduced to your beer process over time while you just grow accustomed to it. Supposedly, homebrewers are more susceptible to this and develop an outbreak after a certain amount of batches made while commercial breweries often take longer to reach a similar point.

I know that lacto-bacillus is more of a sour taste and brett develops more of a horse/ hay flavor and acetobacter is a distinct vinegar/ acetic acid flavor. While the first two develop taste slowly over fermentation/ storage they are often overwhelmed by the larger amounts of yeast we throw in. this acetobacter though is kicking my yeasts' collective butts. You'd definitely know you had a problem if you have what I have. Good luck with your stuff though!

 

[Aloha_Brew]

I don't think you can safely bleach stainless steel.
Try 1 cup vinegar to 5 gallons -- in addition to what the guy above me said re replacing all plastic.
Soak overnight, rinse with super hot (boiling even) water. I would then try a second round of a different cleaner like oxiclean.

I would also replace, not clean, all keg lines.

Sucks to hear about this!

http://www.howtobrew.com/section1/chapter2-2-1.html is the reference I used for cleaning stainless steel with bleach; John Palmer's How to Brew. Gonna definitely try the boiling water and then go for bleach and then PBW again (a more expensive oxy-based cleaner). Will also replace all my keg lines though, just in case, even though I soaked them in the PBW before as noted.

Oh, and unfortunately, it is currently swimming in vinegar of sorts...

 

[NanoMan]

You might try steaming. Get a large metal funnel and invert it in a pot (turkey fryer is good) of boiling water. Place the keg over it for 15 minutes....

 

[Aloha_Brew]

I have a hunch that your keezer itself is infected. You're brewing the beer, and it's fine, as you're not fermenting inside the keezer (at least that's what I presume). You then put the fermenter in the keezer to cold-age/lager, and the exterior of the fermenter is picking up acetobacter while it's in there. As you rack from the now-tainted fermenter (on the exterior), your hands or other instruments are touching that tainted fermenter, and infecting the beer as it goes in the keg.

I actually do place my glass carboy (6.5 gallons) with the usual 5-5.5 gallons of beer to ferment in my deep chest freezer, regulating the temperature with a controller. I then transfer it from that priamry directly into my keg...using it as a secondary/ lager and just serve it from there using party taps, not any type of kegerator setup.

I don't think it is my freezer that is infected per se, as the third keg I mentioned does not show any signs of this infection (and had never been exposed during my move like the other two were) and the amount of beer I put into my growler from the same kegged Oktoberfest is not infected either. It does make sense to clean it out though and I will take up your recommendation to do so. Thanks man.

 

[Aloha_Brew]

Simply leaving a sealed, purged keg of beer at temps above 80 for a few days will NOT spoil the beer. I routinely rack beers from primary to a corny keg and let them sit for several weeks, like a month or two at room temps around 74-76. As long as they are properly sealed and purged, that's the same idea as a secondary fermentation, and would not lead to spoilage for several months without other factors at play.
You had the infection before that point.

I understand how that would make sense but why would only two out of three kegs be infected when they have been handled the same way, unless it had something to do with the beer that was inside them (as they maintained CO2 and pressure even with the beer in the two. Before my move I had kept everything within the same deep freezers and onlythose two same kegs have those problems. So, I know it had to be in those kegs.

Definitely soak in bleach for 24-48 hours, then soak in hotwater baking soda solution for 24 hours to get rid of the bleach smell, then soak in hotwater PBW/OxyClean solution for another 24 hours, then soak in hotwater StarSan solution for another 24 hours. Do all of this with the keg posts, tubes, and lid at the bottom of the keg to soak. Replace all of the O-rings in the keg posts and lid, as well as all of your kegorator lines.

That'll do the trick! That's how I clean and sanatize the kegs I use bacteria and wild yeast in.

Sounds very thorough, but I've read that prolonged periods (greater than an hour) with bleach in stainless steel can lead to corrosion and pitting. What's your ratio bleach:water? Also, I have party taps, not a kegerator setup.

 

[Aloha_Brew]

I've had similar issues with a diacetyl off flavor and my kegs. I've swapped out almost everything plastic and not I am trying new kegs, tubing, faucets. Fortunately the off flavor isn't terrible and the beer is drinkable.

Check you bev tubing, shank and faucet. Really disassemble and scrub them clean. Use form BLC on your tubing.

Diacetyl wouldn't be an infection though, but a process where oxygen somehow gets introduced into the wort and beer over time. That's why there is a diacetyl rest at higher temps to allow it to "evaporate" out for lack of a better term. I think that was my initial problem with my Oktoberfest I just made, as I can still taste a definite sweetness in my growler. That'll be my next thing to conquer after this bacteria problem.

 

[Aloha_Brew]

I would try a bleach solution for the kegs. While it will oxidize stainless, it's not a problem if left for only a few hours. Just don't leave bleach in stainless for days. After you rinse the bleack out well , re passivate and sanitize with a star San solution. I would throw away all rubber, and replace the lines. Them take apart your disconnects as well as shanks and faucets and clean then boil all parts.

I think I'm resigned to the fact that boiling water and a bleach solution, followed by another PBW cleaning before and after these processes, is my next tasking. I really don't want to toss these kegs, somehow develop another infection later on, and be in the same situation. This really sucks by the way...can't even RWHAHB!!!

 

[Aloha_Brew]

You might try steaming. Get a large metal funnel and invert it in a pot (turkey fryer is good) of boiling water. Place the keg over it for 15 minutes....

Can't think of a way to regulate a specific temp though or even if it can be done without ruining the rubber/plastic ends which must be sealed to the keg cylinder with some sort of glue. Kind of hesitant to even add boiling water, but I don't have much choice unfortunately.

 

[TopherM]

why would only two out of three kegs be infected

You said the third keg didn't have any beer in it. Bacteria need something to eat to propogate. No food supply = no bacteria growth.

 

[Bensiff]

Like someone else said, heat only encourages bacteria to grow. I usually wait until I have about 4 dirty kegs and then clean all at once so they can sit all summer in my garage at very high temp and still smell like beer when I open them up to clean.

In general it is pretty hard to get infections but if something sets in it can be a living hell. This is where you break everything down, kegerator in/out lines, weldless fittings, ball valves, everything to its most basic level. Soak it in a cleaner and sanitize. Its not a matter of trying different sanitizers, if you used Starsan, iodopher or whatever and you still have the issue, its because you are missing where it is coming from. Clean your surface areas of your brew area, fridges, kegerator, or whatever equipment you have. Replace your plastic, tubing, and o-rings. Its a lot of work and expense but nothing can make one give up on such a great hobby like having a brewhouse infection issue. Good luck.

 

[midfielder5]

http://www.howtobrew.com/section1/chapter2-2-1.html is the reference I used for cleaning stainless steel with bleach

thanks for the link. I was thinking at first "yeah do bleach" and then google said it would pit SS so I said what I said. JP certainly knows better than me !

 

[patthebrewer]

Cleaning and disinfecting is not really a mystery, it's easy to kill stuff. Even the toughest stuf doenst stand a chance against bleach. If you've taken everything apart and disinfected it(from the keg to the faucet). The taste can not be coming from your draft system, it has to be something else. Have you taken apart your faucets down to the idividual parts? Did any beer backflow into you gas lines......

 

[JuanMoore]

It sounds like you had your infection before you took the beer out of the fridge temps, the fridge temps were just keeping the infection in check.

Agreed. I'd be looking at anything that touched the wort between the end of fermentation and going in the keg.

I understand how that would make sense but why would only two out of three kegs be infected when they have been handled the same way, unless it had something to do with the beer that was inside them (as they maintained CO2 and pressure even with the beer in the two. Before my move I had kept everything within the same deep freezers and onlythose two same kegs have those problems. So, I know it had to be in those kegs.

It's very likely an infection in your racking cane, transfer tubing, or other equipment that touches the beer post fermentation. A tiny infection in something like transfer tubing may only transfer small amounts of bacteria/wild yeast to the beer that passes through it, and in some cases not enough for an infection to take hold in the beer. I once had an infection that I eventually narrowed down to a bottling wand. Only ~1/4 of the beers bottled with that wand ended up infected though.

 

[cpesko]

Have you considered the equipment you are using to transfer to the keg? Hoses autosiphon?

 

[cpesko]

Agreed. I'd be looking at anything that touched the wort between the end of fermentation and the going in the keg.



It's very likely an infection in your racking cane, transfer tubing, or other equipment that touches the beer post fermentation. A tiny infection in something like transfer tubing may only transfer small amounts of bacteria/wild yeast to the beer that passes through it, and in some cases not enough for an infection to take hold in the beer. I once had an infection that I eventually narrowed down to a bottling wand. Only ~1/4 of the beers bottled with that wand ended up infected though.

Yea I am with this guy check your hoses. Racking can.

 

[Aloha_Brew]

Last weekend I cleaned all three of my corny kegs. Did the scrub with dish soap, rinsed with water, added bleach (70ml for the 5 gallons) to water that topped off each keg, rinsed with boiling water, and then filled with water and PBW. I let that sit overnight and then rinsed thoroughly with water before adding StarSan solution, letting that sit for the last week.

Today I emptied the kegs and noticed a white residue around the lower lip of the rubber seal on the removable lid. As I emptied each keg I noticed a few white globules and some dendrite-looking whitish forms. I could see the a similar whitish residue on portions of the side chamber inside the keg also. I'm definitely going to rinse these again and then reapply StarSan before racking my bear, but I just wanted to make sure this wasn't some other type of infection and was only probable residue from the StarSan.

 

[JRems]

It's probably just the star San reacting with the minerals in the water. I get a similar residue if I leave it it for a week.

 

[Aloha_Brew]

So far, so good with the cleaning. Time will tell if the problem is truly solved. I'll taste it again before I hook up any lines to the kegs, just to make sure that if any problem develop they would be more likely to have come from them rather than the keg. Now all I have to do is figure out the best pitching rate for my lagers so they stop developing this annoying sulfur/sweet diacetyl taste! Hopefully, this remains my biggest worry for at least the next few months...

Thanks for all the help everyone, but I would like to note again the following: I used the same equipment over a 6 month period (and about 3-4 brews per keg) but only had a problem with 2 of 3 kegs, and I had cleaned all 3 kegs thoroughly but obviously not enough to stop a distinct sour-/vinegar-like smell from developing in one keg that had just been Star San'd. I understand that an infection needs food to feed on and cannot exist in a "clean" beer spontaneously. That is why these particular facts confused me so much.

Also, it had nothing to do with my fermenters or siphon because the samples I drew and stored in growlers were unaffected. It only started in the keg, and only two of the three I had even though all are stored the same way and handled with the same recycled (cleaned and sanitized) connections. That is what stumped me, and from what I can gather from the previous responses, also seemed implausible to many. Yet, despite my "approved" cleaning methods resulting in a lack of bacteria, it somehow survived a PBW soak and a StarSan coating BUT only in two of three of my kegs.

I cannot explain it, and from the advice I have been given here it seems that my situation was an impossibility, but I can only hope that the symptoms do not return! I shall drink to this and chalk this up to Murphy's Law, rather than find a specific flaw. At the very least I have become more sanitary minded and will take what I have learned with me as I brew more. Thanks again for the support everyone.

 

[fishfoolz]

So far, so good with the cleaning. Time will tell if the problem is truly solved. I'll taste it again before I hook up any lines to the kegs, just to make sure that if any problem develop they would be more likely to have come from them rather than the keg. Now all I have to do is figure out the best pitching rate for my lagers so they stop developing this annoying sulfur/sweet diacetyl taste! Hopefully, this remains my biggest worry for at least the next few months...

Thanks for all the help everyone, but I would like to note again the following: I used the same equipment over a 6 month period (and about 3-4 brews per keg) but only had a problem with 2 of 3 kegs, and I had cleaned all 3 kegs thoroughly but obviously not enough to stop a distinct sour-/vinegar-like smell from developing in one keg that had just been Star San'd. I understand that an infection needs food to feed on and cannot exist in a "clean" beer spontaneously. That is why these particular facts confused me so much.

Also, it had nothing to do with my fermenters or siphon because the samples I drew and stored in growlers were unaffected. It only started in the keg, and only two of the three I had even though all are stored the same way and handled with the same recycled (cleaned and sanitized) connections. That is what stumped me, and from what I can gather from the previous responses, also seemed implausible to many. Yet, despite my "approved" cleaning methods resulting in a lack of bacteria, it somehow survived a PBW soak and a StarSan coating BUT only in two of three of my kegs.

I cannot explain it, and from the advice I have been given here it seems that my situation was an impossibility, but I can only hope that the symptoms do not return! I shall drink to this and chalk this up to Murphy's Law, rather than find a specific flaw. At the very least I have become more sanitary minded and will take what I have learned with me as I brew more. Thanks again for the support everyone.

Speaking of the sulfer/sweet taste, that may be because the pitching temp is too high. It lowers the amount of yeast cells from developing and start to cause the cells to produce a lot of waste that cannot be eaten up later in the conditioning phase because they spent too much time early in the initial pitching trying to eat sugars instead of dividing like they are supposed to. Try pitching at a lower temp and let it gradually come up to the desired temp. The yeast cells will then be able to acclimate to the environment, divide into a ton of healthy cells which will be important later when they are able to eat much more complex sugars and waste products from earlier cells.

 

[Premnasbiaculeatus]

A couple things to ponder on:

If it really does taste like vinegar, the metabolic pathway that turns alcohol into acetic acid is an aerobic one. Depending on various degassing methods many vintners have a tendency to aerate their wines to some extent post primary, but this rarely turns said to vinegar. Acetobacter / Mother of vinegar is basically on everything and is extremely tolerant of low PH, thats why wine makes use sulfates and not starsan in their sanitation processes. Acetobacter shouldn't ruin a beer unless it's severely oxidized. If you're force carbonating with bottled CO2 and purging all the air out of the keg before hand, it's unlikely to be acetobacter.

If it doesn't taste like brett or lacto, you could consider the possibility that the steel of your keg has become porous somehow and is leeching out some nastiness that it dissolved during storage. The fact that the flavor comes out gradually and cleaning and sanitizing doesn't fix the two out of three that are effected could point to leeching.