Possible sources of phenols other than chlorine?

Hi everyone,

Some time ago I brewed a Belgian style using Duvel yeast which I had grown up from a bottle deposit. The beer fermented apparently normally, although I may have gotten my temperature wrong (I fermented it at room temperature, whereas I now understand this yeast is happier when kept a bit cooler than that).

Much to my surprise, the beer turned out to be extremely phenolic. In fact there's so much phenols that I consider it undrinkable. It's like drinking desinfectant.

Now everyone with whom I've spoken immediately shouts "TCP" and points to chlorine as the most likely culprit. Literature tends to back this up. However, I know for a fact that there's no chlorine in the mix in this case. I use borehole water from my own well which is not chlorinated; I do not use chlorine-based chemicals for cleaning or sterilizing, and in fact no chlorine was anywhere near the beer during any step of the brewing process. I use washing soda for cleaning (caustic soda for tough cases) and sodium metabisulfite as a sanitizer. All equipment and bottles are rinsed with hot water (just off the boil) before coming into contact with the wort or beer. None of the above compounds have ever given me any off-flavours so far.

So. Apart from Chlorine which I can garantuee was not a factor here, what other possible factors can lead to the production of phenols or of compounds with phenol-identical flavors?

Any insight in the matter would be greatly appreciated.

Cheers!

// FvW

Chlorophenol is a completely different flavor than phenols. Chlorophenol will have a "band-aid" type taste.

A high fermentation temperature, coupled with a yeast that has the phenolic trait can cause your issue. I am speculating that it was probably under-pitched as well. I would correct those issues and then brew the beer again and see how it comes out.

I agree that the yeast is the likely culprit here. I am overly sensitive to phenolic flavors, and find them off-putting even in many commercial Belgian beers.

Another common source of phenolic off-flavors is tannin from grain husks, extracted from over-sparging, or sparging at high pH.

I agree on the yeast too. Belgian yeast fermented too warm can get lots of phenols.

I had an infected yeast starter, and the only way I knew it was the incredibly phenolic beer that resulted.

Bacterial contamination is often phenolic, as it stressed yeast.

Yooper said:

I had an infected yeast starter, and the only way I knew it was the incredibly phenolic beer that resulted.

Bacterial contamination is often phenolic, as it stressed yeast.

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This is true also, but I suspect that may not be the OP's issue as the Duvel yeast has the phenolic trait itself and most likely was stressed. It would be hard to tell whether the phenol came from wild yeast/bacteria, or the Duvel yeast.