[Calenk]

So a couple months ago I brewed a Kolsch it came out with a very medicinal plastic like off flavour. From what I've read it could have been phenols in the yeast (imperial Dieter) fast forward to last week. Brewed a hefeweizen with wyeast 3638 that I had in the fridge for about 4 months from an overbuild starter. fermented at 68°. It came out with the exact same flavour.  so now I'm not sure what the problem is. The only thing these beers share is the water which is carbon filtered tap water.

[denny]

So a couple months ago I brewed a Kolsch it came out with a very medicinal plastic like off flavour. From what I've read it could have been phenols in the yeast (imperial Dieter) fast forward to last week. Brewed a hefeweizen with wyeast 3638 that I had in the fridge for about 4 months from an overbuild starter. fermented at 68°. It came out with the exact same flavour.  so now I'm not sure what the problem is. The only thing these beers share is the water which is carbon filtered tap water.

Is it possible that your carbon filter isn't working right?

[jverduin]

Phenolic flavors have various sources. Some are more likely culprits and some less likely. Hefeweizen yeast strains and many Belgians are POF+ meaning they are genetically predisposed to producing compounds that taste phenolic. Different conditions (pitch rate and fermented temp) may amplify or subdue the production of those compounds. So for the Hefeweizen, that is a likely explanation as the yeast strain is known to produce it.

For the Kolsch, I think most strains used for Kolsch are not POF+. I do think yeast that are exposed to extremes (ferm temp) “might” express phenolic compounds, but am super sure on that one.

Chloramine or chlorine in the brewing water can make a pretty medicinal / band-aid off flavor, but carbon filtering should address it. It is an easy diagnosis if someone indicates that they use city water but no treatments.

Lastly, a wild yeast infection can create phenolic off flavors.

Maybe do some reading on Kolsch and phenolic sand see if others report issues...?


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[Calenk]

I suppose that's possible the carbon filter isn't working right. I do have a chlorine test I could check it. It's strange how no other beers came out like that just these two.

[kramerog]

If the starter you used was 4 months old then poor yeast health (without making a new starter) I think the problem the problem with the hefeweizen was poor yeast health.  Poor yeast health and even healthy yeast but small pitch size can produce phenolics across different yeasts and beers.

[BrewBama]

Chlorine would probably do it. The easy check would be to change the filter element.

Also, undesirable yeast may be the culprit. How do you sanitize?  Maybe switch to a different one and see if that kills it.

Is there a particular fermenter that these two used in common vs other beers?  Maybe a secret colony of crusties resides in a dark hidden place.

How long was your lag time?  Before the yeast establishes itself, certain gram-negative, indole-negative, short-rod, wort spoilage bacteria have been reported to produce a medicinal phenolic taste in the resultant beer.


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[Calenk]

If the starter you used was 4 months old then poor yeast health (without making a new starter) I think the problem the problem with the hefeweizen was poor yeast health.  Poor yeast health and even healthy yeast but small pitch size can produce phenolics across different yeasts and beers.

No I did make another starter. Seemed pretty healthy. Dropped the beer from 1.050 to 1.012 in about 4 days.

[Calenk]

Chlorine would probably do it. The easy check would be to change the filter element.

Also, undesirable yeast may be the culprit. How do you sanitize?  Maybe switch to a different one and see if that kills it.

Is there a particular fermenter that these two used in common vs other beers?  Maybe a secret colony of crusties resides in a dark hidden place.

How long was your lag time?  Before the yeast establishes itself, certain gram-negative, indole-negative, short-rod, wort spoilage bacteria have been reported to produce a medicinal phenolic taste in the resultant beer.

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I use star san. I'm gonna check the Ph to make sure it's still good. It's probably a month old. Lag time is interesting. I can't remember the lag on the kolsch but the Hefe sat in the fermenter for about 24 hours before I pitched the yeast.

[BrewBama]

Try iodophors to replace the Star San. It’s a killer.

Using an old starter. Using old Star San. Waiting to pitch yeast. I dunno brother. I think you’re living on the edge.

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[MattyAHA]

yeah, i would like others said make sure the carbon filter is working proper and when filtering go thru the filter slower then molasses and maybe even throw a campden tablet it for cheap insurance

[denny]

yeah, i would like others said make sure the carbon filter is working proper and when filtering go thru the filter slower then molasses and maybe even throw a campden tablet it for cheap insurance

1 gal./minute form chlorine, .1 gal./minute for chloramine

[MattyAHA]

yeah, i would like others said make sure the carbon filter is working proper and when filtering go thru the filter slower then molasses and maybe even throw a campden tablet it for cheap insurance

1 gal./minute form chlorine, .1 gal./minute for chloramine

i go even slower, i'm in no rush collecting water