Micro Flavor Machines

By Caroline Hatchett | Megan Swann

By

Caroline Hatchett
Megan Swann
Shadows of Their Eyes: Oak-aged Dark Sour
Shadows of Their Eyes: Oak-aged Dark Sour

When Brewer Jay Goodwin submitted Shadows of Their Eyes (a Belgian-Style Flanders oud bruin) to the 2014 World Beer Cup, he won bronze. He also created a stir. A Belgian judge wanted to know if he added cherries to the beer (he didn’t), and a brewer from renowned Brasserie de la Senne wanted to know how an American brewed such an impeccable beer (he can go to San Francisco to find out). Shadow of Their Eyes did have strong notes of cherry, along with a dark spirit and Sherry-like qualities. While some of those attributes came from the barrel the beer was aged in, much of its characteristic flavor—cherry included—came from the yeast and bacteria responsible for fermenting and souring the beer, respectively. At Rare Barrel, Goodwin and his team are obsessively mapping and chronicling the effect that bacteria, microorganisms, and yeast have on beer—not to mention barrel characteristics, water attributes, time, etc.—all to illuminate the murky world of souring beers. Here’s a primer on where and how flavor develops on a micro level. 

BRETTANOMYCES VAR. DREI AND LACTOBACILLUS DELBRUECKII
These fermentations take fruit well and are great for blending. This is the fermentation used for Ensorcelled (dark sour with raspberries) and in the past, Sourtooth Tiger (golden sour with ginger). The profile features clean, bright acidity. When used in dark wort, this fermentation creates notes of dried fruit—think dried cherries and currants.

PEDIOCOCCUS
As the sole bacteria in a beer, Pediococcus can create a richer, rounder acidity than Lactobacillus, and a fuller, smoother mouthfeel. It works slower than Lacto, and needs to be paired with Brettanomyces to eliminate the diacetyl (a buttered popcorn/butterscotch off-flavor) created during fermentation. Apropos of Nothing (golden sour with lavender and elderberries) was soured solely with Pediococcus.

WILD CULTURE
Rare Barrel has an evolving house culture they call “CY”, and they’re not entirely sure what yeast and bacteria and other microorganisms are present. It’s more funky and complex than some of their controlled pitches, with some lemon rind, stone fruit, and a mild earthy character. The upcoming Map of the Moon (golden sour with apricots) was fermented with this culture.

SAISON SACCHAROMYCES
Rare Barrel uses a number of Saison saccharomyces strains alongside Brett and bacteria. These beers have softer, more aromatic attributes with floral (heather/sage) and spice (white pepper). They’re selective about base beers and secondary ingredients, though, as the yeast character can clash with or enhance the ingredient addition. A recent draft of Soliloquy (golden sour with rosehips and orange peel) and Forces Unseen (blended golden sour) showcase saison.

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