Mystery Infection

[chrisvaf]

Hey everyone. I'll try to keep this post relatively short. I switched to kegging a year ago and 3 out of my last 4 batches have ended up tasting like butterscotch. 2 out of the 3 took a couple of weeks in the keg before the taste changed and my latest (an Imperial IPA) tasted off right after the keg was carbonated. All 3 beers tasted great prior to the butterscotch flavor.

I'm extremely careful with regard to cleaning and sanitizing but regardless, I took everything that touches the beer post-boil apart, cleaned everything thoroughly, boiled everything stainless for 20 minutes, replaced all plastics (including PET carboys), sanitized everything using StarSan and I'm ready to brew another batch.

Upon reading tons of posts on infections, I decided to take apart my CO2 manifold just to check it out. The one beer that still tastes great is an American Wheat, which I had connected to Line 1 of the manifold. The other 3 beers had been connected to lines 2 and 3. Below are pictures of all 4 lines. Unless I'm seeing things, lines 2 and 3 look like something is growing in there. So, a couple of questions for those more knowledgeable than me.

1. Am I going crazy or do lines 2 and 3 look like they could be the source of my infections?
2. Assuming the answer to 1 is yes, what's the best way to clean and sanitize/sterilize the manifold? Should I replace all gas lines as well?

Thanks in advance!

 

[JONNYROTTEN]

Seems odd a co2 line would give off flavors let alone something growing in it. Nothing lives in an oxygen free environment....I'm going with something else as your issue

 

[Dcpcooks]

Butterscotch is a fantastic descriptor of diacetyl. Perhaps the difference is your old beers had a bottle conditioning phase to clean up the beer.

When you switched to kegs you lost that extra time and clean up. I’d look at my ferm schedule and incorporate a drest as needed.

It’s possible your dirty lines are causing a problem and you should clean them regardless.

 

[chrisvaf]

Butterscotch is a fantastic descriptor of diacetyl. Perhaps the difference is your old beers had a bottle conditioning phase to clean up the beer.

When you switched to kegs you lost that extra time and clean up. I’d look at my ferm schedule and incorporate a drest as needed.

That’s what I thought but the beer tasted great initially, then the butterscotch taste kept getting worse and worse, to the point where I had to dump 2 kegs. . It was undrinkable.

I only primary and both beers spent 5 days at 66 (until Active fermentation was done). I then bumped the temp up to 70 for another 3 weeks. I ferment in a temp controlled chest freezer. I would think that would be enough time for the yeast to clean up any remaining diacetyl?

 

[JONNYROTTEN]

Are you using the same type of yeast for the batches with issues? Maybe your sensitive to the flavor it produces? It's been awhile since I used it but think I got butterscotch from using 34/70

 

[augiedoggy]

I see nothing odd in those photos, is it just me?

if it were all your kegs I'd ask if your using a beverage co2 tank or one filled at a welding supply store as its not uncommon for oils to get into the tank when filled with nonfood grade equipment designed for welding gas fill ups on grubby old tanks that have been sitting god knows where.. Praxair is one of my customers and they explained the difference to me as most of the time you will be fine but you can run into a problem using a welding gas only supplier.
I would think though if it was oil of some kind it might effect head retention.. Short of an issue with the beer itself I have no other ideas..

I wasnt even aware that an infection could cause what your describing.. the only infected beer I had was very bad and there was no doubt what happened.

 

[chrisvaf]

Are you using the same type of yeast for the batches with issues? Maybe your sensitive to the flavor it produces? It's been awhile since I used it but think I got butterscotch from using 34/70

US-05 was used for two, and Danstar Nottingham for the other, but before kegging I brewed many batches that I bottled (almost exclusively used US-05) and nothing ever tasted anywhere close to what this tasted like. I brought a sample of each to my LHBS and they picked off the diacetyl right away. It wasn't a mild taste or smell - it was disgusting. Smelled like butterscotch, tasted like butterscotch. No hop aroma at all.

In taking all my equipment apart I noticed the inlet of my chugger pump had a raisin-sized dried up "hop debris". In my setup I drop my recirculating immersion chiller into the kettle with 15 minutes left in the boil. The ball valve from my kettle connects to my pump, then back to my copper recirculating arm into the kettle. I imagine the 15 minute boil will kill anything.

Regardless, in taking everything apart I boiled everything stainless, chucked everything plastic, with the exception of the camlock gaskets. I bought new ones but they're way thicker than the current ones I had and I can't close the camlocks so I instead soaked the old ones in PBW and cleaned thoroughly before running boiling water through the whole setup. I plan to brew again this weekend. i guess we'll see what happens.

 

[chrisvaf]

I see nothing odd in those photos, is it just me?

if it were all your kegs I'd ask if your using a beverage co2 tank or one filled at a welding supply store as its not uncommon for oils to get into the tank when filled with nonfood grade equipment designed for welding gas fill ups on grubby old tanks that have been sitting god knows where.. Praxair is one of my customers and they explained the difference to me as most of the time you will be fine but you can run into a problem using a welding gas only supplier.
I would think though if it was oil of some kind it might effect head retention.. Short of an issue with the beer itself I have no other ideas..

I wasnt even aware that an infection could cause what your describing.. the only infected beer I had was very bad and there was no doubt what happened.

My CO2 tank was supplied and filled by my LHBS. I purchased it brand new and I have yet to refill it.

As for the pictures, attached are 2 more closeups, one with what I perceive as clean and one that I perceive as dirty. What I presume is the check valve is white on the 2 outside lines and darker on the 2 inside lines. Without even taking a picture that much is very clear when I look inside. It's probably just me being paranoid trying to track down this issue but dumping 2-3 kegs of what should have been good beer is not easy so I'm looking at everything.

My concern is that beer accidentally got into the CO2 line. The lines are red therefore hard to see what's actually inside.

 

[Dcpcooks]

I still think it’s fermentation and diacetyl. How are you taking temps during fermentation? A d rest is only two days long at 5 degrees over fermentation temps. It’s recommended to start the drest with. .02-06 gravity points left before you reach final gravity.

If the yeast floc out before they have cleaned up then the precursor to diacetyl, acetolactate will still be present in the beer. At that point any oxygen pickup during transfer will oxidize the acetolactate into diacetyl.

I’m unaware of a cause for diacetyl other than fermentation time and temp. And the only thing that’s changed is the kegs.
Diacetyl will be reduced during the bottle conditioning phase. It due to yeast in suspension and warming storage temps.

You can try raising temps a bit higher while your still in primary.

You can try doing o2 free transfers to the kegs.

You can make sure your thermo well is in contact with wort during fermentation.


Good luck

 

[JONNYROTTEN]

He used 05. It doesn't need a Diacetyl rest. It fermented at diacetyl rest temps to begin with.

You sure you weren't eating hard candies before drinking

 

[Dcpcooks]

05 can produce diacetyl. Any yeast can produce it since acetolactate is a normal part of the byproducts produced during the growth phase of fermentation. Lacto and pedio can also produce acetolactate.

It’s possible the gear was infected with lacto if he’s milling grain in the brewery. It’s highly unlikely the gas in line is the intro source.

So he’s either got a serious infection in the brewery or it’s fermentation or oxidation of the precursor which points back to fermentation.

It’s easy to rule out fermentation. Take two samples of wort roughly 6 oz each. Heat one sample to 130-140 degrees for 30 min. Cool both samples in an ice bath and taste them both. If diacetyl is present it will pop after being warmed and cooled.

 

[chrisvaf]

You sure you weren't eating hard candies before drinking

LOL - maybe I was!

Some additional history here. Before kegging I used to (stupidly) mill my grains in my fermentation room not knowing that was an issue, and I did have infections in 2 bottled batches (one gusher and one American Wheat that turned copper/purple in color). I then moved my milling to the garage to eliminate that potential risk.

I seriously hope it's nothing in my fermentation room however now that I'm pretty much starting from scratch we'll see how it goes. I also did try an oxygen free transfer from my better bottle to my keg in my last IPA (kegged 2 weeks ago). Had some issues with hops clogging my jumper line but I think I'll be able to fix that in my next batch.