Phenol Flavor Keeps Coming Back

[Floydmeister]

So a few months ago I had a nasty phenol flavor show up in all of my beers. I switched to RO water and got new fermenters and for awhile there it was gone.. but now it's back and it's in everything. The smell when I remove the lid of the fermenter is just "plastic" and thats the general overall flavor other than the first intial taste. So I have some questions because what I've researched and what I'm experiencing doesn't seem to add up.

There are three possible causes that I know of:
1. Chlorophenol
This is what I was pretty sure my problem was. I've switched to using store bought RO water form a dispenser. I use this water for everything. My sanitizer is mixed with it and my brewing water is 100% RO every time with just basic minerals added as per the water chemistry primer thread. I've also started to use campden tablets just as a "hey why the hell not" measure. If chlorine/chloromine is still causing this somehow, I give up.

2. Leftover Cleaning Product
My cleaning/sanitizing process for fermenters is pretty simple. Once I rack it out of primary for packaging I rinse out my PET carboys as best as I can, and then fill them with really hot water and PBW. I let them soak in this mixture overnight and then dump it out the next day. I then rinse them as best as I can and fill them about 1/10th full of RO/Sanitizer solution, cap it off, and give it a good shake. During brew day I continue to occasionally shake it to get sanitizer everywhere and then dump it out right before I fill it up with wort. From what I've read, StarSan shouldn't cause any off flavor. I also haven't heard of any off flavors from a PBW soak.

3. Infection
Aren't infections sour? I love sour beers and none of my beers are sour. This is closest to the taste of a brett beer if anything, but those guys let brett sit for a year before they get any of that funky flavor and mine are overwhelmingly phenol after two weeks, while still in primary.

I do use pure o2 on these beers. But I got this flavor way before I started using o2. Guys at my local homebrew club are of absolutely no help so far. The beer that I brought in I was told 'something happened during fermentation'. This happens on beers where I make a starter using liquid yeast or when I pitch multiple or single dry packs. I've also got fermentation temperature in check. I've been doing a week in the 60's for ales, with a 10* bump after a week/when it slows and a cold crash a few days after that.

If it's an infection, how the heck is it popping up in only two weeks? How do I eradicate it? If it's airborne, can you eradicate it from the brewery?

I'm at a complete loss here. Nothing is making any sense. Thanks for any help.

 

[doug293cz]

Have you tried RO water from a different source? That's the only suggestion I have, as you have tried most everything else.

Brew on

 

[aeviaanah]

You clean your ball valves lately?

 

[Floydmeister]

You clean your ball valves lately?

No ball valves to clean. I dump the wort from my kettle by hand into my fermentor using a funnel.

 

[saltymirv]

Sounds like you have an infection from wild yeast/some microbe. Infections do not have to be sour. It's somewhere in your system, whether it be your funnel, siphon, primary fermenter or lid. Its likely living in scratches in the plastic.

If you have a spare fermenter (that hasn't had this flavor) you can try fermenting in that and see if you get the flavor.

 

[porterpounder]

Soaking your PET overnight in cleaner isn't necessary and may be doing something to the surface of the carboy. Most also don't recommend water above 140 F in the vessels. Throw a rag in there with about 1/8 of the bottle filled and shake the hell out of it for a few minutes and its' going to be clean.
One cause of plastic flavors/aromas in beer is severe underpitching, especially with wheat-beer yeasts. Make sure you have a healthy pitch.

 

[The_Bishop]

You say you are using pure O2, I assume you are using a diffusion stone? Have you boiled it? They're a prime spot for harboring bugs is not kept clean.

 

[Floydmeister]

Soaking your PET overnight in cleaner isn't necessary and may be doing something to the surface of the carboy. Most also don't recommend water above 140 F in the vessels. Throw a rag in there with about 1/8 of the bottle filled and shake the hell out of it for a few minutes and its' going to be clean.
One cause of plastic flavors/aromas in beer is severe underpitching, especially with wheat-beer yeasts. Make sure you have a healthy pitch.

I don't think I'm underpitching because I'm making starters, and I've tried using two dry packs at a time as well. It's also a consistent flavor between over 5 yeast strains so far. The hot temp of water intrigues me though... What would it do if it were too hot? My house water does get insanely hot for some reason.

You say you are using pure O2, I assume you are using a diffusion stone? Have you boiled it? They're a prime spot for harboring bugs is not kept clean.

Uh oh. No i don't boil it. I've been running it for a bit once done and before using it again to clear anything out under the assumption that pure o2 would kill microbes. I then soak it in starsan solution for about a minute before using.

Looking at my notes, there are beers that didn't use pure o2 and were without off flavor; they were in new/newish 1st or 2nd time use fermenters as well though. I didn't have o2 last time I got this flavor. Can an infection really throw off that flavor in two weeks?

 

[The_Bishop]

I occasionally boil my O2 diffusion stone to clean it out and insure nothing's taken up residence in it. I'll also soak it in starsan starting right at the beginning of the brew day.

 

[Floydmeister]

I guess I will try boiling my o2 stone & wand. As for my fermenters that have had this problem... are they ruined? I can't help but wonder if this could also be from the pbw soaks as I didnt have this issue with new fermenters. Actually in my early days before any problems I was using dawn dish soap and never got off flavors like this.

 

[NTexBrewer]

I'm not at home at the moment so I'm going off memory from recently reading the Yeast Book. Most sacc yeast has lost the ability to produce phenols with the exception of German heffeweisen yeast and most Belgian yeast strains. Brett does produce phenols. So if you are truly tasting, smelling phenols and you are using yeast that is not known for producing phenols it is a sign you have an infection.

 

[Floydmeister]

Can an infection produce that much phenol character in two weeks though? Isn't that extreme?

 

[NTexBrewer]

Can an infection produce that much phenol character in two weeks though? Isn't that extreme?

I don't know the answer to that question. Looking through the Yeast Book this morning they have an off flavor chart in the back. Phenols can be caused by wild yeast, under pitching, and chlorine