What could be causing strong phenolic flavor in beer?

[u/AdventureousWombat]

I've been homebrewing for 5 years or so, and this is the first time I'm experiencing this. I had 2 recent batches become very phenolic; tastes almost like band aid

Not 2 batches in a row, I had a couple good batches between them, but pretty close

These 2 batches had different recipes and different yeasts, one was a witbier made with 3944, another was sour with lallemand philly sour

I can't think of anything I've done wrong with these batches; The last batch, the sour, I'm pretty sure I've sampled a bit while bottling, and didn't feel any off flavors; But after a couple weeks of bottle conditioning, the band aid flavor is definitely there

The only thing I'm doing differently is the sanitizer; My local homebrew shop didn't have StarSan, and I bought BTF Iodophor instead; But it couldn't be residual iodine from the sanitizer? Google search couldn't find anything

Is there a known issue that causes phenolic band aid flavor?

[u/RumplyInk]

Lack of proper Sanitization can lead to infection and this possible off flavor. Also, chlorine and chloramine are typical perpetrators of bandaid or plasticky flavors. I would double check the sanitation practices (with the new solution) and get some campden tablets

[u/Living_Bill_5456 → u/RumplyInk]

Perché le compresse di metabisolfito , a cosa servono 

[u/xnoom]

https://beerandbrewing.com/off-flavor-phenolic/

Based on your description, most likely causes sound like chlorine/chloramine in brewing water, or infection by wild yeast.

But after a couple weeks of bottle conditioning, the band aid flavor is definitely there

That could point to an infection somewhere in the bottling equipment, or the bottles themselves.

But it couldn't be residual iodine from the sanitizer?

No, only something chlorine-based like bleach would do that.

[u/AdventureousWombat → u/xnoom]

no bleach involved anywhere. probably not the bottles themselves, since phenolic flavors are equally present in all bottles. My sanitation procedures are already pretty paranoid, but I guess it's time to sanitize my bottling equipment with extreme prejudice, it seems like the most likely source

[u/chino_brews → u/AdventureousWombat]

I agree with /u/xnoom. There are only three, likely potential causes:

1. Your flavor description is quite on-the-nose for chlorophenols. They are formed instantly when polyphenols from hops or malt touch free chlorine. The chlorine can be in your tap water or from sanitizers. Some sanitizers include or produce chlorine, even if it's not listed on the label (but not BTF Iodophor).
2. If not chlorophenols, then wild yeast, which can produce undesirable phenolic off-flavors.
3. The other, more remote possibility, is cross-contamination from a prior, phenolic, domesticated yeast you used recently, such as a saison yeast. It shouldn't taste like band-aids, but humans are super tasters of phenols and also experience them in a variety of ways.

A less likely, potential cause is leaching of plastic off flavors from plastic equipment.

[u/warboy]

Your witbier strain is phenolic off flavor positive. This should cause spicy phenolics in your beer and if you had some of that yeast carry over into the Philly Sour batch could have caused problems there.

But usually band aid or antiseptic phenolics is caused by chlorine in your brewing water.

[u/Ziggysan]

Was there a break in the water mains upstream of your point of use? If so, SOP is to send a chlorine and chloramine spike through the affected pipes once service is restored.

[u/barley_wine]

Years ago I had something like this happen. The beers all started off good, then after a few weeks they got real dry and then started to taste like a bandaid. In my specific case, I’m pretty sure it was a wild yeast infection from the bottling bucket spigot.

Ended up putting all of my plastic stuff in the top shelf of the dishwasher and washing on high heat. Also got iodophor for everything else. It got rid of it.

But you’re using iodophor so my fix won’t work for you. I did still use starsan when brewing:

If it continues, I’d look at replacing your auto siphon, bottling bucket spigot and hoses.

[u/CascadesBrewer → u/barley_wine]

I had a similar thing happen several years ago. A few batches tasted fine when I kegged them, but developed a strong plastic/band aid flavor over a few weeks. It was an infection that carried over from one batch to the next*. A solid round of cleaning and sanitization fixed the issue.

*The second batch was a Pale Ale that I harvested the yeast from. A while later I used that yeast in another batch forgetting it was from the infected batch. That led to another band aid beer that got dumped and another round of cleaning an sanitization (lucky it was a 1 gal batch this time).

[u/HighTurning]

Things that come to mind:

• Bottle conditioning at high temps
• Both strains and styles could be phenolic naturally so little change in parameters could cause them to go phenolic.
• Pitching yeast at slightly high temps.

[u/gofunkyourself69]

Do you brew with tap water? If so, how do you treat your water prior to brewing?

Tap water can vary wildly throughout the year not only in mineral content but also in chlorine/chloramine levels, especially when a municipality has been doing line work.

[u/Delicious_Ease2595]

Betting on contamination during bottling or late fermentation. Phenols don’t just appear.