Wheat produces more phenols?

**ElDuderino** · 07-07-2009, 06:59 PM

I hope I didn't reply to the following too fast:

The banana and clove are flavor notes emerging from the fermentation of the beer--thanks mainly to the wheat--which produces more phenols (the source of these notes).
from the Sierra Nevada Kellerweis post on this blog Beervana, the Blog

This seemed wrong and I responded with the following:

It is probably petty to mention, but the following is not really corect:
The banana and clove are flavor notes emerging from the fermentation of the beer--thanks mainly to the wheat--which produces more phenols (the source of these notes).
It is the yeast strain itself in combination with fermentation temperature which determines how much phenol and ester character is contributed to a beer. It would do the same with a beer made from all barley. The wheat addition leads to a lighter/drier beer and can also contributes proteins with add to the haze appropriate to the style.

Do you all agree with my response or did I just make myself look like an idiot?

bnscherm · 07-08-2009, 05:24 PM

You're an idiot.

Just kidding, sounds right to me!

**olllllo** · 07-08-2009, 05:37 PM

A little of both. Wheat and the mash influence how many 4-Vinyl guaiacol precursors occur.

Quote:

The phenolic flavors originate from phenolic acids naturally found in malt, especially ferrulic acid. Strains of yeast with the right enzymes transform these phenolic acids through a decarboxylation reaction into aromatic phenols, such as 4-vinyl guaiacol. These compounds are often described as possessing clove-like and vanilla aromas.

http://netbeer.org/content/view/33/48/1/1/lang,en/

http://brewiki.org/BeerFlavours

mysterio · 07-08-2009, 05:38 PM

Actually, you're both right to an extent, wheat malt DOES have an effect on higher alcohol production. See this presentation by Eric Warner:

Innovations In Wheat Beer Brewing For Aha Conference

Isoamyl alcohol is in turn esterified into isoamyl acetate, responsible for banana aroma. So wheat malt contains more precurser.

But you're right, it is primarily a yeast effect.

**olllllo** · 07-08-2009, 05:41 PM

It's kind of like asking, "What produces more gold? The ground or digging it up?"

**ElDuderino** · 07-09-2009, 05:54 PM

Thanks for all the replies. I will check out the links you all sent. Now I'm an idiot that can muse on decarboxylation and 4-vinyl guaiacol :-)

**Budzu** · 07-09-2009, 05:55 PM

A very recent experience was pretty eye-opening for me: Earlier this year I brewed a german hefe, fermented pretty cool at 64. Delicious phenols came out that were very appropriate.
Just a week ago I kegged an American style wheat beer, brewed with once again about 50% wheat malt, and standard american yeast. It also had phenols and banana notes! It was fermented cool as well. I was very shocked to get these flavors that I thought came completely from the yeast.

28 batches so far this year and I'm learning something new every time!