Wild Yeast and phenolic off-flavors...

I've brewed over 50 batches of beer now, and entered about 12 or so in various competitions over the last couple of years. Several of these beers have had comments suggesting a medicinal, smoky, phenolic off-flavor and aroma, which I can detect as well. Some of these beers never had the water treated (and their IS chlorine in the city water where I live), some had water treated with campden tablets, and one or two were carbon-filtered.

All of the judges suggest the start of a wild yeast infection. However, my question is this: if it IS due to wild yeast, would the infection and off-flavors/aromas not worsen over time? In some cases, the beers were months old and the flavor is barely there, and in other cases, I don't notice a worsening in the flavor of the beer many months after entering the competition.

I think that my sanitization procedure is pretty solid... I hope so, anyway. If I'm filtering my water now, I wouldn't expect chlorine to be an issue. Not sure what else I can do, but I want to try to eliminate the wild yeast factor... I can't help but think if it was an infection, things would worsen noticeably over time.

Both are likely candidates although if you're having the same results after using campden and carbon filters it's less likely the water is the issue. Off flavors from wild yeasts normally don't get worse over time because once they run out of food they stop producing the chemicals that lead to off flavors.

Are you using repitched yeast? Topping up with unboiled water?

Usually not using repitched yeast, and definitely not topping up with unboiled water.

Maybe there's an issue with my sanitizing, although I'm not sure what that would be. I use Starsan, and I'd like to think I'm pretty meticulous with it; but maybe I'm missing something, or it has something to do with my environment...

I think you're on the right track by focusing on the equipment and water. Here's what I think I would do:

- Clean/replace some of your plastic and vinyl components. I'd replace any vinyl tubing you're using. I'd check and thoroughly clean you bottling bucket's spigot and bottling wand components, replace if need be. If you think any of your plastic equipment might have scratches that prohibit Star San for making contact, I'd replace those too.
- Try another sanitizer on your equipment. Try iodophor or bleach, rinse, then Star San just to be cautious.
- Brew a batch using purchased RO water (make mineral adjustments as needed).

Pie_Man said:

I think you're on the right track by focusing on the equipment and water. Here's what I think I would do:

- Clean/replace some of your plastic and vinyl components. I'd replace any vinyl tubing you're using. I'd check and thoroughly clean you bottling bucket's spigot and bottling wand components, replace if need be. If you think any of your plastic equipment might have scratches that prohibit Star San for making contact, I'd replace those too.
- Try another sanitizer on your equipment. Try iodophor or bleach, rinse, then Star San just to be cautious.
- Brew a batch using purchased RO water (make mineral adjustments as needed).

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Thanks, that's helpful. It's along what I was thinking as well, especially about giving RO water a try.

ReverseApacheMaster said:

Both are likely candidates although if you're having the same results after using campden and carbon filters it's less likely the water is the issue. Off flavors from wild yeasts normally don't get worse over time because once they run out of food they stop producing the chemicals that lead to off flavors.

Are you using repitched yeast? Topping up with unboiled water?

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So, if an unintential addition of wild yeast can cause these off flavors, I assume there is no remedy for an infected batch?

Like the OP, I have brewed well over 50 batches in the last two years and this latest was my first lager attempt. I am curious that if leaving the kolsch on the yeast for near two months can contribute to this? I am so pissed!!!

Anyways, I feel my sanititation is good enough but I will admit drawing more than a few samples during the course of the lagering cycle. One thing I noticed during the diacetyl rest was some mold on the side of my tub that I use to transport carboys in. I assume it grew due to the condensation. Can Mold produce these same flavors? Very plastic like, maybe tasting similar to a throat spray. Hah! Just read a bottle of throat spray, it contains 1.4% phenol.

Didn't mean to hijack, just don't want to start another thread.

Also, just to mention, I don't think the OP mentioned what he uses to clean his equipment prior to sanitizing with Starsan. I'm sure you already know this but thought I'd bring it up just in case: Starsan does not clean your equipment, it only sanitizes clean equipment so it's very important that you're cleaning your gear with something like PBW prior to sanitizing with Starsan or Iodophor or whatever.

maddad said:

So, if an unintential addition of wild yeast can cause these off flavors, I assume there is no remedy for an infected batch?

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No remedy. I had a "band aid" beer that I kegged hoping it would not suck as bad as I knew it did. I traced the infection back to a contaminated yeast that was rewashed. The beer wasn't as terrible as it could have been- but it never got better, either. I ended up dumping 9.5 gallons of it.

Yooper said:

No remedy. I had a "band aid" beer that I kegged hoping it would not suck as bad as I knew it did. I traced the infection back to a contaminated yeast that was rewashed. The beer wasn't as terrible as it could have been- but it never got better, either. I ended up dumping 9.5 gallons of it.

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Reminds me of throat spray. I also have a sore throat. Active ingredient in throat spray = Phenol.

I wil be dumping 4 of 5 gallons before Thanksgiving. Going to drink a gallon of it to see if phenolic beer is just as good as throat spray.:rockin:

My first lager attempt so it hurts just a bit. Will find comfort in my Porter.

WilliamWS said:

Also, just to mention, I don't think the OP mentioned what he uses to clean his equipment prior to sanitizing with Starsan. I'm sure you already know this but thought I'd bring it up just in case: Starsan does not clean your equipment, it only sanitizes clean equipment so it's very important that you're cleaning your gear with something like PBW prior to sanitizing with Starsan or Iodophor or whatever.

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Yeah, I know that Starsan doesn't clean. It depends on the equipment; with some buckets I'll use just dishsoap and hot water to clean, but with fermenters, for example, I use Aseptox to clean.

I think super stressed yeast can release these flavors. I lost a few batches using super old yeast that I tried to revive. Are you consulting yeast calc? I know sometimes the starter size estimates can be high but I have been having much better luck going by its numbers.

jtejedor said:

I think super stressed yeast can release these flavors. I lost a few batches using super old yeast that I tried to revive. Are you consulting yeast calc? I know sometimes the starter size estimates can be high but I have been having much better luck going by its numbers.

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I rarely re-use yeast, and when I do I make sure to wash it and pitch the proper amount. I always go by the yeast-pitching calculator at mrmalty.com as well.

There's no remedy for bad flavors once they are there. If you catch the infection early enough you can try to stop further fermentation. If you kegged the beer I'd look at hitting it with campden but if you bottled you could bottle pasteurize. It won't make it taste better just won't let it get worse.

I've been through a similar issue that I'm 100% sure was wild yeast and it hid in my heat exchanger. There are only so many cold-side places to hide. Plastic tubing is cheap, so that is an instant, low-cost way to start: throw it out.