Ethyl Acetate to Phenols?

[biertourist]

I remember a thread around here somewhere where AJ spoke to the difficulty with which ethyl acetate is converted to other chemicals; I've had a braggot which ended up being partially fermented with the wild yeast from unpastuerized honey that was pitched into secondary. At first the beer had LOADS and LOADS of ethyl acetate. (I brought 1 gallon out of 5 up to 80 C to boil off the ethyl acetate (and ethanol, unfortunately) to try and reduce the ethyl acetate.) -Immediately after adding it back to the main batch for the first day or too the ethyl acetate levels were still very high.

Now the ethyl acetate seems to have toned down a bit but I've got the "bandaid" phenols that drive me crazy. --It certainly SEEMS like the ethyl acetate was converted to phenols by tasting it over time but is this even theoritically possible? (I don't think it is and my guess is that I succeeded in reducing the ethyl acetate while the yeast (even at serving temps) created phenols slowly.)


Adam

[BDawg]

Wild yeasts are notorious for throwing phenolics. All yeasts throw them do one degree or another. Most strains don't produce enough to rise above taste threshold. Others (Belgian and Weizen strains) throw far more.

[De-Geert]

It certainly SEEMS like the ethyl acetate was converted to phenols by tasting it over time but is this even theoritically possible?

No, that's not possible.

[ajdelange]

Obviously plants (the common source of phenols in beer) are capable of synthezing them from ethyl and acetyl like molecules and yeasts with the POF gene certainly produce phenolics but whenever I hear "plastic" or "bandaid" I think of chlorphenolics which are usually found when the water contains chloramine and no treatment is done for it. Furthermore, as this has happened presumably since the beer has been taken off the yeast the conversion would have to be from some non biochemical reaction so I can't imagine that conversion is the cause.

Thus the first question is as to whether your water supplier chloraminates. If it does the second question is as to whether you used a campden tablet or GAC filter to remove the chloramine. If the answer to this question is no then I'd say the proable cause is chloramine and I'd hypothesize that you didn't notice it at first because it was masked by the ethyl acetate.

[biertourist]

I ALWAYS add 1/4 camden tablet to 5-6 gallons of water.

I should also add that I am VERY sensitive to phenols and although I don't mind banana or clove phenols in small doses I've definitely learned that the threshold at which I am turned-off by phenols in beer seems to be lower than most people. -I'd even say that my tongue starts to feel almost numb towards the end of a particularly phenoly beer.

I might not have a proper phenol vocabulary; I put phenols into one of 3 categories that I can recognize:
banana
clove
YUCK/ Bandaid / tongue numbing


-Its very much possible that I didn't notice it because there was LOADS of ethyl acetate before I boiled 1/5th of the batch. (I've never been able to identify with the "typical" flavor descriptors of ethyl acetate as quickly as with this beer; the concentrations were so high it was "by-the-book" ethyl acetate; -not good!) I also pitched 75 grams of crushed juniper berries (that very obviously had the white tint of wild yeast on them) towards the end of secondary fermentation, which is why I theorized that the phenols may have come from the juniper berry wild yeasts.


Adam

[ajdelange]

I ALWAYS add 1/4 camden tablet to 5-6 gallons of water.

Scratch that one then.

I should also add that I am VERY sensitive to phenols and although I don't mind banana or clove phenols in small doses...

Banana isn't a phenol but an ester: amyl acetate. Clove is a phenol: 4 - vinyl guaiacol.

I might not have a proper phenol vocabulary; I put phenols into one of 3 categories that I can recognize:
banana
clove
YUCK/ Bandaid / tongue numbing

As noted above banana does not belong on the list, clove does and certainly phenols can be resposible for the tase/sensations in the third item.

-Its very much possible that I didn't notice it because there was LOADS of ethyl acetate before I boiled 1/5th of the batch. (I've never been able to identify with the "typical" flavor descriptors of ethyl acetate as quickly as with this beer; the concentrations were so high it was "by-the-book" ethyl acetate; -not good!) I also pitched 75 grams of crushed juniper berries (that very obviously had the white tint of wild yeast on them) towards the end of secondary fermentation, which is why I theorized that the phenols may have come from the juniper berry wild yeasts.

I'd point the finger at the juniper berries - either because of their intrinsic tannin content or because some wild yeast contains the POF gene or both.