National Homebrew Club Ireland

I spotted this discussion on hobbybrauer.de and it's quite specific about the development of phenols in weissbier and the 45°C step rest.

"Es geht bei Weißbier für den phenolischen Charakter aber speziell um 4-VG. Dessen Precursor Ferulasäure wird beim Maischen bei 45°C enzymatisch aus seiner Bindung mit Arabinoxylan gelöst. Das pH-Optimum der beteiligten Enzyme liegt hierbei nahe 6,0, insofern ist flyings Aussage schon korrekt. Eine Säuerung nach der Rast bei 45°C kann aber tatsächlich technologisch sinnvoll sein. Einige Weißbierbrauereien betreiben sogar noch eine Würzesäuerung (z.B. Schneider-Weisse)."

[Translation]
With weissbier the phenol character is all about the 4-Vinyl guaiacol (4-VG). This precursor of Ferulic acid during mashing at 45°C is enzymatically split from it's binding with Arabinoxylan. The optimum pH for this enzyme is pH 6.0, in this respect flyings (forum member) statement is correct. To sour after the 45c rest can be technologically useful. Some weissbier breweries even do an acidification as standard practise.

I hope this might help some of you out who are not happy with the results you're getting with weizens, but basically I'd adopt a german stepped rest schedule and start with strike at 45c and then do a rest at that temp for 15-30 minutes.(shorter 10 mins according to biertourist).

The "ferrulic acid rest" is definitely the traditional German prescription for how to get more clove notes; it's definitely done @ Schneider. BUT... hefe strain selection and temperature possibly play an even bigger role.  The Schneider brewery admits that their yeast strain is a descendant / "house strain" adapted from the Weihenstephan strain but they also freely admit that when they use the commercially available Weihenstephan strains in the same conditions they get more esters than they do with their house strain.

Many of the highly phenolic German Weiss biers also use open fermentation to reduce pressure which does elevate phenol AND ester levels, so consider an open fermentation, too.


I can say from definite experience you do NOT want to listen to those who would tell you to just underpitch to get more phenols -the phenols that you get are different and disgusting "yeast stress" phenols.


For what it's worth Kai Troester ("Brau Kaiser") did a side-by-side test on a wheat beer fermentation with a ferulic acid rest and without and found no appreciable differnce in the phenolic characteristics or intensity between the two beers. http://braukaiser.com/blog/blog/2010/06/04/how-much-effect-does-a-ferulic-acid-rest-have/

That does go against the traditional German wisdom, though.

If you DO do a ferrulic acid rest, keep it short ferulic acid is released rather rapidly so 10 minutes should do; you don't want a 30 minute or longer ferulic acid rest unless you want a glass of cloves. -and I'm talking from memory but I thought that the ferulic acid rest is also a low temp protein rest at which some proteolytic enzymes are also active so you can kill beer head if you go too nuts. (although that should be way less likely with the huge protein load of a 50% wheat grist)



Adam

I did 2 hefes recently with Schneider Weiss tap7 dregs using a ferulic rest, the 2nd using some of the yeast from the first batch. The first batch fermented at17° was disappointing but definitely had clove. The 2nd batch fermented at 19° had a lovely amount of banana. Not too much but very present.
Didn't have a control batch without the ferulic rest to compare against so can't claim to know if it makes a difference

Ok am I the only person on the planet that can't stand this style?
I think it's because I associate it with toothache

Quote from: CH on May 21, 2016, 12:50:09 PM
I think it's because I associate it with toothache

You lucky B'stad.

I wish I was given Hefe Weizzen as a kid when I had tooth ache!

All I were given were a wet stone to suck on!

Quote from: CH on May 21, 2016, 12:50:09 PM
Ok am I the only person on the planet that can't stand this style?
I think it's because I associate it with toothache

+1 ;)

Weizenbock and weisbier I struggle to drink after doing the judging course. My brain screams WRONG when I taste the phenols... :(

Sent from my E5823 using Tapatalk

Quote from: CH on May 21, 2016, 12:50:09 PM
Ok am I the only person on the planet that can't stand this style?
I think it's because I associate it with toothache

You are NOT, I feel the same way; I thought I might be one of the few people who is super phenol sensitive.

I like a lot of commercial Bavarian hefeweizens that are banana-heavy, though. I have serious problems drinking many of the craft beers in the Netherlands because so many of them use high phenol producing Belgian strains for most of their beers.

I like phenols very restrained.  If I brew a Belgian style, I use the Achouffe / Ardennes strain for exactly that reason. (Plus that strain is made by magic gnomes, so it's AWESOME.)


Adam