The popularity of sour, funky beer is not an accident, because brett is amazing. It can consume almost any sugar source including those in oak, dead yeast, and other long chain sugars left untouched by normal saccharomyces strains.
After a beer is completely dry, brett can sull break down and survive on carbohydrates, proteins, and even alcohol; continuing to create flavors and aromas months after fermentation is complete. Brett strains possess glycosides which allow them to break down the flavor and aroma compounds of ingredients such as hops and fruits to create flavors often described as tropical, which are not found ili any other beer styles. It can metabolize small amounts of acetic acid (vinegar) and other organic acids that may be present to produce unique esters such as ethyl acetate, which can add pear-like flavors (but, in high doses, can become nail polish, so be careful of oxygen exposure). It can scavenge oxygen to help keep beers tasting fresh and preserve hop flavor and aroma. Unlike other yeasts, it can survive in very Mgh alcohol beers and at a very low pH. As Chad Yakobson from Crooked Stave found, it can even turn the disgusting bile-like flavor from butyric acid into ethyl butyrate which gives a distinctive pineapple aroma.
Brettanomyces can be counterintuitive in the most novel ways. When used in secondary or for bottle conditioning, brett will completely dry out a beer and create very funky and farmhouse like flavors. But when used as the primary fermentor, it can create very clean and delicate beers that don’t necessarily become super dry. Despite there being only a few strains commercially available, the genetic structure of brett is twice as complex as normal ale yeast strains, giving it the potential for larger intraspecies variation. Some new micro-labs such as Bootleg Biology and The Yeast Bay have started releasing some really exciting new strains this year.
Very little research has been published on the characteristics of brett, so this information is just the tip of the proverbial iceberg. It is a fun time to be in the beer industry! Nobody should be wary of attempting to make sour and wild beers anymore. There is so much information available now on sites such as Milk the Funk and The Mad Fermentationist, and on the Sour Hour podcast. Chad Yakobson’s interview on The Brewing Network is full of very good knowledge. When used correctly, brett can make the most delicious of beers. So give it a try!
Kevin E. Osborne, “Bruery Batch 1731 Homebrew Competition Winner”, Beer Paper LA (December 2015), 21.