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Grizzlybrew 07-10-2010 12:50 PM

Looking for Complete Phenol and Ester Info
 
I was hoping someone here could help. I did a quick search, but couldn't find exactly what I was looking for. I am interested in finding a resource that will give more complete info on phenolic compounds and esters typically produced in beer.

Looking for more of the following type of info:

Esters:
ethyl-acetate - pear-like (low levels) - solvent-like (high levels)
isoamyl-acetate - banana-like

Phenols:
ferrulic acid + yeast = 4-vinyl guaiacol (cloves)
chlorophenols - result of residual chlorine in brewing process
polyphenols (tannins) - extracted from malt/hop matter

I would like to find a list of the different chemicals/compounds/processes involved in phenol/ester production and their flavor and aromatic qualities.

And more importantly, how to manage them (i.e. increase, decrease, etc.)

Thanks in advance!

Grizzlybrew 07-10-2010 04:01 PM

bumpity bump bump...

david_42 07-10-2010 05:16 PM

I've never seen this information anywhere. Be interesting if someone can find it.

Maarten 07-10-2010 06:16 PM

Give me a gas chromatograph and I will tell you. Seriously, I will search the scientific literature and will come back if I find something.

ghpeel 07-10-2010 11:49 PM

From Radical Brewing, by Randy Mosher:

Esters: Fruity or sometimes spicy aromas mostly due to yeast activity. At high levels in Belgian yeasts, especially when fermented at higher temperatures.

Ethyl acetate: Fruity, nail polish
Isoamyl acetate: Banana
Ethyl hexanoate: Ripe apple

Phenol: A wide range of chemicals, many of which are noxious - smokey or medicinal, for example. Desireable ones may me produced by specialized Belgian yeasts such as strains used in Bavarian Weizen or Belgian ales.

4-vinyl: guiaicol: "Clove" aroma found in Weizens
4-ethyl phenol: Barnyard, a marker for Brettanomyces activity

ghpeel 07-10-2010 11:52 PM

More......

Phenolic: A broad category of flavor gremlins. The worst of them - 3, 5 dimethoxyphenol - is an indicator of wild yeast infection, and smells like an electrical fire. Other, more subtle, even pleasant ones, can come from certain yeasts strains (weizen) or honey. UserL a nice fresh Weizen for the clove-like yeast character; honey diluted 1:4 in water; for the really nasty one, perhaps a piece of phenolic circuit board, the amber colored kind, freshly rasped or broken for intense aroma. Use: don't bother to dunk them in beer, just sniff the objects.

Nickme23 07-11-2010 12:25 AM

Hey Grizzlybrew, I have a good book on wheats and if you don't mind waiting a day or two I'll try to compile some of the info for ya and post it here. I'm by no means an expert although I might be tending towards an EAC, but I can definitely compile other people's great ideas :D

a10t2 07-11-2010 02:29 AM

Get a copy of Principles of Brewing Science by George Fix. It has essentially everything a brewer would ever need to know about fermentation byproducts, including flavor thresholds and the metabolic pathways for the common ones.

Grizzlybrew 07-12-2010 07:54 PM

Thanks for the responses so far!

Quote:

Originally Posted by ghpeel (Post 2153972)
From Radical Brewing, by Randy Mosher:

I actually have this sitting in my library, but haven't flipped through it in a while.

Quote:

Originally Posted by Nickme23 (Post 2154004)
Hey Grizzlybrew, I have a good book on wheats and if you don't mind waiting a day or two I'll try to compile some of the info for ya and post it here. I'm by no means an expert although I might be tending towards an EAC, but I can definitely compile other people's great ideas :D

Looking forward to it. Is it Stan H's new book by chance? I just read the other day that wheat contains such a higher level of ferrulic acid than barley - that's why hefeweizens can have such a strong clove flavor...

Quote:

Originally Posted by a10t2 (Post 2154109)
Get a copy of Principles of Brewing Science by George Fix. It has essentially everything a brewer would ever need to know about fermentation byproducts, including flavor thresholds and the metabolic pathways for the common ones.

I'll definitely check it out. I'm also hoping that Jamil and Chris White's new yeast book covers this stuff as well.

Nickme23 07-12-2010 11:12 PM

Quote:

Originally Posted by Grizzlybrew (Post 2156346)
Thanks for the responses so far!

Looking forward to it. Is it Stan H's new book by chance? I just read the other day that wheat contains such a higher level of ferrulic acid than barley - that's why hefeweizens can have such a strong clove flavor...

"Brewing with wheat: The 'wit' and 'weizen' of world wheat beer styles"
by Stan Hieronymus

If that's the book and you've read it then I'm not going to bother researching it :P Hah


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