If you’ve been hanging around breweries and craft beer bars lately, you’ve probably heard people mention Brett - particularly in reference to sour styles of beer. But what is it? What is it doing in beer? What’s all the hype about?

Brettanomyces, or Brett for short, is a type of yeast. In both brewing and winemaking, yeast is the main facilitator of fermentation. It feeds on the sugars present in the wort (brewed beer before its fermented) or grape juice and yields both alcohol and carbon dioxide as byproducts. Brettanomyces is prized in the brewing industry for its ability to produce acetic acid and other compounds that give beers all kinds of unique, funky and exciting flavors and aromas.

Positive descriptors such as earthy, fruity, tart, floral and woody are often associated with Brett beers, as are some seemingly negative ones, like barnyard, hay/horse blanket, funky cheese and musk. Believe it or not, even those qualities can give both beer and wine very desirable, deep flavor profiles when present in small quantities. It is Brettanomyces, often along with the help of lactic acid-producing bacteria, that gives many of your favorite sour beer styles, their unique and dry funkiness that you can’t quite put your finger on, or get enough of. World famous brews like Belgian Lambic, Gueze, Flanders Red, Oud Bruin, Saison/Farmhouse, and many American Wild Ales are all made with this rockstar fungus.

But let’s back up for a second. Where does it come from? In the wild, Brett grows on the skins of fruit. Brett is not often intentionally introduced to wine, and its presence, at high enough levels, is often mistaken for cork taint or spoilage. It sometimes makes its way into beer and wine as a contaminant, usually carried by insect vectors – think fruit/drain flies – or hiding inside improperly sanitized barrels. Brett is generally only intentionally used in significant quantities for some Chardonnay, “natural wines” and a few red varieties.

However, in the beer brewing world Brett is intentionally sought after for many open fermented beer styles, particularly lambics and Flanders Reds. While American craft brewers seek out Brett hoping to add a unique complexity to their brews.

It is important to note that not all Brett beers are necessarily sour. When Brett is in the presence of large amounts of oxygen, acetic acid production can be high, and therefore producing the tart and funky flavors most often associated with this yeast - but creative brewers have learned that Brett will only yield a slight tartness when utilized in different ways.

Bear in mind, however, that Brett beers may not be for everyone - at least at first. Owner of Carolina Beer Temple, Rob Jacik, had this to say about his first encounter with a true Belgian sour-ale:

About 20 years ago, back when I was almost exclusively a pilsner, pale ale and IPA drinker, I was allured by the label of the Belgian classic, Duchesse de Borgogne. Having no idea what a sour-ale was. I purchased what appeared to be an exquisite brew.
After enjoying a few IPAs, I decided to crack open the bottle of Duchesse for the first time. To me, it smelt like vinegar and tasted terrible! I was appalled! I thought the beer had gone bad and I had no idea a beer could sour like that.
I asked around only to find out that Duchesse is one of the best examples of a Flemish Red in the world! What? It’s terrible, I protested.
With a bit of research and quite a few more tastings, I learned all about sour-ales and how they are deliberately made to taste funky and tart. These taste nothing like their pilsner and IPA cousins in the craft beer world - but are equally regarded as true masterpieces of brewing in their own right!
In time, I have grown to truly appreciate a good sour-ale - tangy, crisp and surprisingly refreshing - with Duchesse de Borgogne being regarded as one of the best sour-ales I know!
- Rob Jacik

Now, let’s talk about some of our favorite Brett beers.