Brettanomyces is a strain of yeast, used to fully or partially ferment and in some cases, to bottle condition beer, in which a small dose of yeast is added to the bottle before the beer undergoes some type of storage, conditioning period or shipment.

In order to fully begin to understand this illusive yeast strain, we had to wrap our head around the different strains that are used, in brewing, because much of the time we just say “brett” when referring to this yeast, which is only partially correct. There are four strains known to the brewing world, but only two are typically used: Brettanomyces Bruxellensis (also called Brettanomyces Lambicus) and Brettanonmyces Anomalus (also called Brettanomyces Claussenii). Aroma and flavor descriptors often range from horse blanket, barn yard, funk, fruitiness (especially pineapple), spicy and even smoky to leathery and acidic. The two strains that have not been experimented with much, to-date, are Brettanomyces Custerianus and Brettanomyces Naardenensis. Beers fermented, even in part, with Brettanomyces are often drier, which is a character of final beer flavor that is appealing to some.

Brettanomyces-fermented beers are not always sour, despite common misconceptions. They certainly can develop extremely generous sour and acidic character, over time. Predominant characters in “brett” beers tend to be more of pineapple, hay, and barnyard funk, which increase with intensity as the beer ages. Beers known for having “Brett” character have, in large part, been beers from Belgium, such as Flanders Red, Oud Bruin, Lambic and Gueuze styles, as well as some farmhouse beers.

“Brett” or “Brettanomyces” has been around for hundreds of years and literally translates to “British Fungus” but has become more wildly (pun intended) spoken about in today’s craft brewing industry, as the number of breweries is nearing 7000. More breweries means more creative brewing minds, which inevitably equals innovative styles or twists on classics. Still, though, beers with Brettanomyces account for less than five percent of the beers in our stores.

So why are we dedicating time and energy to something that affects such a small percentage of the beers, and thereby customers purchasing these beers? As we learned from Professor Piendl of the Technical University at Weihenstephaner, yeast is the spirit of a beer. Working to better understand and be able to explain all beer ingredients to our customers, helps us to be better beer-cierges, ultimately.

While “Brett” can be a funky and off-putting resident in some beers, there is no doubting that this yeast adds character and creativity to beer and in an industry that continues to be on the rise, we look forward to continuing to explore its’ character.

Featured image courtesy of Craft Beer & Brewing Magazine