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General Category => Yeast and Fermentation => Topic started by: wilsonbt on March 18, 2010, 08:46:57 PM

Title: Souring Fermentation
Post by: wilsonbt on March 18, 2010, 08:46:57 PM

I recently had the opportunity to tour the New Glarus Brewing Company as well as sample some of their beers.  I tried the Old English style porter and was shocked to the unusual sour taste.  Looking on their website, it says they performed a "souring fermentation."  I was curious is anyone knew what is meant by "souring fermentation" as I don't have a clue.

Title: Re: Souring Fermentation
Post by: MrNate on March 21, 2010, 03:56:21 AM
Some critters (like Lactobacillus) make acids that create a sour flavor.
Title: Re: Souring Fermentation
Post by: wilsonbt on March 21, 2010, 10:44:02 PM
So, would that be a bacteria they add?  Or is that something that is just a result of an open air fermentation?
Title: Re: Souring Fermentation
Post by: Kaiser on March 21, 2010, 11:50:56 PM
What about adding lactic acid taste?  How much cheating would that be?

Kai
Title: Re: Souring Fermentation
Post by: majorvices on March 22, 2010, 01:24:00 AM
Well, IMO, for an historic English ale you need a bretttanomyces strain. Brett isn't sour by itself but is essential in historic British styles and is also essential in rounding out true souring bacteria strains (such as pedio or lacto) because it helps eliminate diacetyl created by those bacterium.
Title: Re: Souring Fermentation
Post by: The Professor on March 22, 2010, 01:27:20 AM
What about adding lactic acid taste?  How much cheating would that be?

Seems to me that would be a sensible and more controlled way to accomplish the same thing (incrementally, until the desired result is reached), rather than letting wild bugs have at it over time. 
Title: Re: Souring Fermentation
Post by: MrNate on March 22, 2010, 01:28:39 AM
It's all about the profile, man! You wouldn't just chuck in some melanoidin and call it a decoction, now would you?

In all seriousness I've considered adding in a bit of distilled vinegar rather than going through the whole souring shtick, but there's a reason we still call it a hobby.
Title: Re: Souring Fermentation
Post by: majorvices on March 22, 2010, 01:36:02 AM
(With all due respect, Kai.) You guys who think that you can cheat by adding a little lactic acid don't know much about the complexities of controlled (if you can even call it that) souring. I have been experimenting for about 5 years and I can tell you, it simply ain't that simple! A lot of (hopefully) pleasant, complex flavors are created during the aging/souring that simply can;t be recreated by adding a bit of acid.

BTW: OP, the book you need to get is, without a doubt, is "Wild Brews" by Jeff Sparrow.
Title: Re: Souring Fermentation
Post by: Kaiser on March 22, 2010, 01:56:05 AM
Let me continue the topic of adding acid in a different thread. I'm thinking about an intesting subject.

Kai
Title: Re: Souring Fermentation
Post by: abraxas on March 22, 2010, 02:52:34 AM
I was given a 4 pack of that for Christmas, it's interesting but just wasn't my thing. 

Interestingly, someone had brought over a six pack a few weeks later of the Cracked Wheat (I think, I just can't remember for sure) and it tasted like it had undergone some souring as well.  I've always heard there's some risks involved with brewing with Lactobacilli  and was wondering if it was an unintentional contamination. 

Title: Re: Souring Fermentation
Post by: euge on March 28, 2010, 06:43:33 PM
Per my preferences I can't stand it. I can smell it in a fermenter and pick up the taste immediately. Really a disappointment when it happens- I'll pitch a batch out in a heartbeat if it has this characteristic.