Experiment: phenols and lowering alcohol content

At a recent meeting of our homebrew club, someone was talking about their beer tasting of band-aids, and how that flavor doesn't age out.

That got me thinking about the low-alcohol experiment that Biermuncher did a few years back. I was wondering if the heat would also drive off the flavor compounds that make up the Band-Aid flavor.

Now that I look at the science, my guess is "no" - the boiling point of ethanol is 172F, where the boiling point of phenol is 359F - but hey, it's worth a shot, right?

I wanted to start out by expanding a bit on BM's work in the previous thread by getting some good measurements. Unfortunately, I don't have the SG or ABV of the beer I'm using, but I was able to get relative starting/ending numbers.

So first I weighed the beer and took a gravity reading: 317 grams at 1.003. I then put it in a pan and kept it between 175 and 180F for 30 minutes.



While I was waiting, I boiled a big starter for my Oktoberfest lager. I thought the steam coming from the mouth was cool



Then I chilled it down with my high-tech cooling apparatus.



Once it was cool, I weighed again and took another gravity reading: 247 grams and 1.013! I didn't expect to lose 70 grams - that's 22% of the original beer. I'm definitely going to have to double-check that on the next bottle.

Not knowing the OG or ABV of the beer, I don't think we can calculate exactly how much alcohol was driven off, but it's obvious that quite a bit was.

So now that's done, I'll do the same with the Band-Aid brew, being more careful to avoid oxidation so we can have a reasonable flavor comparison.

-Joe

nostalgia said:

So now that's done, I'll do the same with the Band-Aid brew, being more careful to avoid oxidation so we can have a reasonable flavor comparison.

-Joe

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Very cool experiment!

I'd love to have a lower ABV session beer with all the great taste of an IPA/APA. I've been trying to brew a low ABV beer for several years now.

Interesting. I'm reading that phenolic flavors in beer are not actually caused by phenols. It's a side effect of esters, which boil at 171F, and/or the conversion of ferrulic acid into 4-vinyl guaiacol.

Fascinating I may have to do this to a pint of other beers just to see what the effect is on them.

-Joe

nostalgia said:

Interesting. I'm reading that phenolic flavors in beer are not actually caused by phenols. It's a side effect of esters, which boil at 171F, and/or the conversion of ferrulic acid into 4-vinyl guaiacol.

Fascinating I may have to do this to a pint of other beers just to see what the effect is on them.

-Joe

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Well, what about "chlorophenols"? When I have tasted phenols in beers that I've judged, using chlorine/chloramine based water seems to have played a part.

If it's chlorophenols, and not a side effect of esters, would that have a different reaction?

If the flavor comes from phenols of any sort, I'd expect heating to 180F to have no effect on them. It appears chlorophenols don't start boiling until 327F.

-Joe

If the taste/smell is bandaid or plastic like the cause is very probably chlorphenolics caused by residual chlorine (free or bound as in chloramine) in the water. We sincerely hope that there is no actual phenol (carbolic acid) in your beer so the boiling point data for that substance can't be much of a guide but AFAIK chlorphenols aren't volatile at temperatures near that of boiling water.

If the water authority is known to use chloramination or if a glass of the water still smells of chlorine after standing over night or if addition of a pinch of powder from a Campden tablet removes all chlorine odor then it is likely that chloramine in the cause of the problem. Next time the beer is brewed add 1 Campden tablet for every 20 gal of water treated. If the resulting beer is free of the bandaid taste/smell then chloramine is confirmed. If it isn't , then I'm pretty much out of ideas.

When beer is analyzed for its alcohol content it is distilled. Fifty mL DI water is added to 100 mL beer and the resultant mix distilled until about 95 mL has been collected. This is deemed to have gotten all the alcohol but if you observe the process it is pretty plain that most of it comes over early on - you can see that the first condensate has "legs" which disappear in the typical beer after about the first 10-15 minutes (from commencement of condensation) of the distillation. Thus I believe you have driven out most of the alcohol in your experiment. I can't immagine the residue tastes very good, however.

There was a Brew Strong Q&A with Charlie Bamforth where he mentioned a non-alcoholic beer he made while in Saudi Arabia. He said they 'distilled off' the alcohol but that a ton of other things also get lost and you then have to add them back. He said it's still not right and at best you end up with something that is 'beer-like'.

ajdelange said:

I can't immagine the residue tastes very good, however.

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SpanishCastleAle said:

He said they 'distilled off' the alcohol but that a ton of other things also get lost and you then have to add them back. He said it's still not right and at best you end up with something that is 'beer-like'.

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BierMuncher's results seem to be different:

BierMuncher said:

I finally got around to sampling my NA beer I de-balled last week. It was one half of my 10-gallon batch of Anchor Steam Ale (Ale Yeast).

The best part. It tastes fantastic. I bought a couple bottles of the real deal for a taste comparison and the commercial version is a bit dryer than mine, but I did mash at 156 to keep a bit maltier taste.

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So we'll see.

-Joe

De gustibus non est disputandem.

The admission fee to the tower that straddles the border between Bahrain and Saudi Arabia includes a beverage of choice at the "bar" at the top. Unfortunately the choice does not include anything alcoholic but they did have a non alcoholic "beer". Given that was the closest I could get, that's what I took and it was pretty awful - sort of like unfermented wort. Similar experiences in Kuwait. I agree w/ Dr. Bamforth.

The comment about not tasting good was stimulated not so much by those experiences (and fortunately real beer was available in both Bahrain and Kuwait) as by the idea that removing the alcohol by boiling cooks the beer. When non alcoholic beers are manufactured other less destructive means are used such as vacuum or dialysis or fermentation with strains that do not produce much alcohol. The result still doesn't taste very good (IMO) but better than I would expect boiled beer to taste based on the way it looks and smells.