Tuesday, November 5, 2013

Brett-Spiked Saison Experiment

For awhile there, I had a serious problem...

In addition to keeping up a mixed culture for wild beer, I amassed quite a collection of individual Brettanomyces strains. Cultures from homebrewers, limited lab releases, interesting strains from commercial breweries - I hoarded them all. They occupied my entire growler collection. I did my best to keep them all separate, hoping to find The Midas Strain. 

I want to evaluate the flavor profiles contributed by these strains in several applications: 
  1. Secondary Fermentation (inoculation at bottling). Most viable (i.e. least risky) option for commercial brewing; easy to compare Brett contribution vs. control. 
  2. Secondary Fermentation (inoculation after alcoholic and lactic fermentation). Most applicable to mixed fermentation methods (including barrel conditioning). I also believe the most interesting Brettanomyces activity occurs at low pH. 
  3. Mixed Fermentation (inoculation in primary). Contribution within a mixed culture fermentation.
In this experiment, I bottled a simple saison with one of three single Brettanomyces strains. I kept some 'clean' bottles for control samples, and dosed some of the remaining bottles with a mixed culture.

Though I consider it a failed experiment, I thought I'd share the results and (more importantly) lessons learned.

The results of the experiment were unremarkable. Though I have used some of these strains with great success in the past, the resulting flavor profiles in these samples were subtle. I believe the lack of character is due to over-pitching. In his 2011 NHC presentation, Chad Yakobson suggested bottle conditioning with approximately 100,000 cells/mL or inoculating a conditioning ("secondary") vessel with 0.5 - 2 million cells/mL. I dosed each bottle with about 2 mL of fresh slurry, which is about 68 million cells/mL (assumed "thin slurry" per Mr. Malty). The high density of cells drove attenuation past 1.000 but provided little in terms of flavor and aroma.

The additional attenuation also increased bitterness and revealed flaws in the base beer. Looking back at my notes, I allowed fermentation to free-rise from 62F to 70F in the first 24 hours. I also added too much hops. A healthy fermentation and attention to detail: the foundation of all great beer, obviously neglected on this brew day. 

I plan to repeat this experiment with more cultures and a well-brewed base beer. To achieve adequate pitching rates, I intend on diluting each slurry with sterile water prior to dosing. I would also like to lower the pH of some samples to observe flavor profiles at varying levels of acidity. 

Time to brew up some saison!

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