Secondarily Wild
Though spontaneous fermentation is rarely practiced in the United States, a few pioneers have incorporated wild native yeasts into select specialty beers. Russian River Brewing, long regarded as an innovator in interpretive Belgian-style ales, has experimented broadly with secondary fermentation in oak barrels. In 2004, owner/brewer Vinnie Cilurzo initiated the first in a series of beers that would later be blended, bottle conditioned and sold under the name Beatification.
Early production runs of Beatification were fermented with a commercial Belgian ale yeast, then aged in oak barrels previously used by New Belgium Brewing to condition their sour beer, La Folie. The result was a tart, golden ale of 40% unmalted wheat called Sonambic—a contraction of “Sonoma” and “lambic” first coined by Brian Hunt of neighboring Moonlight Brewing. Different vintages of Sonambic ales were blended to create Beatification.
Two years later, Cilurzo took Beatification to the next level by eliminating its primary yeast and allowing the beer to sit “horny” in tanks that expose the unfermented wort to the open airs. The beer is then fermented in oak wine barrels for up to 20 months. Though these barrels are too old to contribute oak tannins or wine flavor, they house “a cocktail of bugs and critters” that ferment Beatification into a sharp, acidic ale with native microbe character.
Meanwhile, in Colorado, Bristol Brewing Co. began experimenting in 2003 to create a series of barrel-aged sour beers under their Skull & Bones label. Their beers also undergo a primary fermentation with a commercial ale yeast, then age in oak Jack Daniels barrels inoculated with local microbes.
Bristol benefits from having a full-time microbiologist on staff. Ken Andrews collected a bouquet of local microflora from the fruits of raspberry bushes growing in Cheyenne Canyon outside Bristol’s 17-bbl brewery in Colorado Springs. The berries hosted two local strains of Saccharomyces, one Brettanomyces, and both Lactobacillus and Pediococcus bacteria.
Andrews grew a culture of these samples into a carboy of yeast slurry. Then he and brewer Jason Yester fed the mix to the barrels along with some honey to stimulate a secondary fermentation. Some beers get treated to further additions of fruit juices, caramelized apples or other inventive adjuncts. They then cask-condition for a year or more before serving.
Though not all of Bristol’s wild yeast beers are affected with prominent sourness, the unfiltered ales have been described as having, “lambic qualities” and their Cuvée earned a silver medal at last year’s GABF in the sour ale category.
