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-   -   How much effect does a ferulic acid rest have? (http://www.homebrewtalk.com/f128/how-much-effect-does-ferulic-acid-rest-have-122375/)

Kaiser 06-04-2009 03:12 PM

How much effect does a ferulic acid rest have?
 
Last night I took some time to publish the results of a side-by-side regarding the ferulic acid rest when brewing Weissbiers:

My Brewing Log | How much effect does a ferulic acid rest have?

Conclusion: For the chosen yeast holding the ferulic acid rest didn't make any noticeable difference in the clove flavor that was produced during fermentation. While additional experiments should be made to confirm these findings it is very much possible that this rest is not worth the additional work.

Next time I'd like to repeat the experiment with an array of Weissbier yeasts to see if different yeasts respond differently to that rest.

Kai

SpanishCastleAle 06-04-2009 03:25 PM

Interesting. I've recently brewed a few Belgians as well as a Weizen and Dunkleweizen and every one of them has way more clove than banana. The Belgians/Dunkle all rested the whole mash @ ~100 F during the first decoction but the Weizen was a simple temp ramp mash (starting @ 144 F).

Would it still be OK to leave the mash at acid rest temps for a decoction? I was trying to stay out of the protein rest range...any lowering of the pH would have just been a bonus with the light Belgians.

Kaiser 06-04-2009 03:51 PM

The source I have come across suggest the pH for the ferulic acid rest to be above 5.7. A higher pH like that will also suppress protoelytic activity and this is why I didn’t add the acid malt to lower the pH until I was in the sacharification temp range.

Even w/o that I don’t think that there is a problem in holding the main mash at that temp while the decoction is heated and boiled.

Kai

pjj2ba 06-04-2009 07:17 PM

So I went to dig up a link for a 2004 paper I read on ferulic acid release and on my way, found two newer papers that look like nice reads. The second one is very pertinent to this thread. In my quick look over the paper, it looks like more time might be needed at FA rest temps to get a really noticible difference. I have another paper that highlights the differences between barley varieties in esterase levels and FA release. I can dig up that link if interested

2008 Formation of 4-vinyl and 4-ethyl derivatives from hydroxycinnamic acids: Occurrence of volatile phenolic flavour compounds in beer and distribution of Pad1-activity among brewing yeasts

2008 Release of phenolic flavour precursors during wort production: Influence of process parameters and grist composition on ferulic acid release during brewing


2004 Ferulic acid release and 4-vinylguaiacol formation during brewing and fermentation: Indications for feruloyl esterase activity in Saccharomyces cerevisiae

twofools 07-18-2012 10:29 AM

How much time is recommended for the FA rest? (I only have access to the abstract.)

AnOldUR 07-18-2012 10:38 AM

Quote:

Originally Posted by 944play (Post 2153355)
Check out the chart on page 85 of Brewing with Wheat. It shows that a 10 minute ferulic rest roughly doubles the perceived phenol.

.

pjj2ba 07-18-2012 02:27 PM

It looks like a relatively short rest will give a good increase in FA levels. If you want maximum levels, it is going to take 2 hrs.

http://cdn.homebrewtalk.com/images/4...tion-55738.jpg

enricocoron 07-18-2012 06:18 PM

Weihenstephaner and Augustiner have very noticeable clove flavors, very little bananna. If you are going for a flavor profile similar to those beers I would think being traditional Bavarian brewhouses they do a FA and protein rest so you may as well. The conventional wisdom is 50/60/70 Celsius.

DSmith 07-18-2012 09:24 PM

The original poster used Vienna malt for his Hefe. The chart in the post above may only be applicable with pilsner malt so there's another factor than just a temperature/time to consider.

http://forum.northernbrewer.com/viewtopic.php?f=5&t=75368&start=0

"But Vienna is more highly kilned than Pilsner and the enzyme that liberates the ferulic acid is fairly heat liable (it starts to denature quickly in the upper 40C). A similar problem exists with the phytase which is used during the classic acid rest and only the lightest malts actually have that enzyme and can be used for an acid rest. Based on that statement there should be only little ferulase activity from the Vienna malt. This leaves the wheat malt which I assume has that enzyme as well. While wheat contributes less ferulic acid than barley malt it still contributes a significant portion.

But this is a possible explanation why I didn’t see much difference. There may not have been much ferulase in the mash to begin with b/c I used Vienna malt. Which means when I repeat this experiment I’ll should use Pilsner malt instead."

twofools 07-18-2012 09:47 PM

How about regular ole american 2-row? or British 2-row? Any chance of getting FA out of those?


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