Acid rest

[TrustyOlJohnson]

Does an acid rest do anything other than drop the pH into a healthy range for the mash? I tend to do a decoction or single temp infusion mash, but rarely with an acid rest, and my pH ranges from 4.8 to 5.2. Would I gain anything with an acid rest for a hefeweizen recipe where I'm trying to increase clove phenolics?

 

[billl]

The literature seems to be mixed. A ferulic acid rest definitely produces ferulic acid. That's the precursor to 4-vinylguaiacol ie the clove phenolic.

With wheat, it looks like much of the same process just happens naturally during fermentation with or without the specific mash step.

So, I'd give it a try and see how it works with your particular recipe. If that doesn't get the flavor you are going after, you can look at fermentation variations - ie lower pitching rates, less O2, higher temps.

 

[Lefou]

An acid rest isn't what you really want for clove. An acid rest is done at a lower temperature than the ferulic rest and releases phytase present in lighter kilned grains. It's something brewers used when they wanted to decrease mash pH without adding lactic acid.

Increased clove phenolics can be achieved three ways.
Use a ferulic acid rest. If I do one, it's around 113F for 20-30 minutes - which is the same temp head brewer Hans-Peter Drexler of Schneider Weisse fame uses (love Schneider wheats, BTW). Ferment on the lower end of your yeast's temperature range, and use a yeast known to produce the phenolic. Some yeasts like WLP320 are neutral, but can produce phenolics when temperatures are out of the low to median range.
http://allaboutbeer.com/quirks-of-brewing-ferulic-acid-rest/

 

[arctic78]

http://braumagazin.de/article/brewing-bavarian-weissbier-all-you-ever-wanted-to-know/


Have a read of this it may be useful to you.

 

[TrustyOlJohnson]

All comments much appreciated!

 

[Lefou]

Have another.
I have Colby's blog bookmarked. Not many updates for a while since the book came out but his multi-part series on wheats is something you may find interesting. Passing it on - don't forget Parts 1, 2, and 4.
http://beerandwinejournal.com/german-wheat-beer-iii/

 

[Smellyglove]

The shortcut to phenols is the yeast strain. WLP380 would be a good choice for clove. It has a pretty defined clove-character if you cap it at 17C for the fermentation 1st gen. If you do a ferrulic acid rest, you get some more, but not extra much of the clove, but you'll get some more citrusy tones to it.