Saturday, July 12, 2014

Quick piece on attenuating beer up to and past 8% abv w/lacto/pedio

Sour Recipe Considerations

First off, pedio and lacto don't like working above 8%.  Some say they work more slowly, others say they just won't work.  Secondly, Brett will work upwards of 18%.  With those constants, let's assume the beer attentuates down and hits 8%, and as a result pedio/lacto will take a back seat to Brett for the duration of fermentation/conditioning/aging.

Conclusion #1 - The further the beer has to attenuate to 8%, the more souring we will get because it is the pedio and lacto that are the main souring agents in a beer. In other words, time below 8% is proportional to perceived souring.

Conclusion #2 - After 8%, Brett funk continues to increase with time and sour character stays relatively flat because Brett, as the primary souring agent, is less effective than lacto/pedio. 

With that in mind what recipe considerations might the learned homebrewer derive?

1. Starter - an underpitch will reduce attenuation thereby leaving more residual sugars (bug food).

2.  Specialty malts - the use of a higher percentage of specialty malts will leave additional residual sugars (bug food) available to the bugs later.  Keep in mind, the use of roasted malts must be restrained as these bugs, especially Brett, accentuate the astringent character in these malts and can often lead to an undesirable perception of astringency.

3. Simple sugars - consider that their use will only make the wort more fermentable leaving (less bug food) for later and a higher alcohol now, thereby closing the gap to our 8% transition from lacto/pedio character development to Brett character development

4. Mash temp:
A. In 100% Brett fermentation: Chad Yakobson of Crooked Stave likes rolling with standard mashes around 152. (more bug food)

B. Vinny Cilurzo of Russian River likes to go high, 160 plus.  Of course we dont want to kill the enzymes, so be aware of calibration errors in your thermometers if your going to go for an all star mash temp of 168. (lots more bug food)

5.  Fermentation profile: Pitch below optimum fermentation range and allow free rise into the optimal range, then bring the ambient temp up to meet the yeast as fermentation settles (and the temperature begins coming back down) to complete the fermentation in the optimum range.  This cooler fermentation profile will reduce attenuation in primary. (Yes, more bug food)

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