Sour beers are some of the most refreshing, as well as the most complex, types of beer out there.
Some have mouth puckering sourness and others are like a fine wine.
But, the fact that they are rare and a bit expensive makes them much harder to get acquainted with, but they are really worth the effort.
In fact, the lighter examples of sour beers can also be some of the best warm weather beer out there.
But, what makes a beer sour, exactly?
Here’s a refresher: beer is fermented primarily with one of two species of brewer’s yeast - Saccharomyces cerevisiae (for ales) and Saccharomyces pastorianus (for lagers).
These two species convert the sugars in the wort to alcohol and leave behind some trace flavors and aromas, ranging from fruitiness, bubblegum, cloves, etc…
There is another species of yeast, know as Brettanomyces, or Brett, as well as several species of bacteria, that take what we would normally think of as a beer and turn it sour.
Now, “sour” is a very broad term, and if you taste a beer expecting just one type of flavor you may be surprised.
The variety of flavors they can produce varies widely, some are described as vinegar, “barnyard”, smoky, wooden as well as just a general sour flavor like in fruit juice.
These organisms also ferment different sugars than the standard brewer’s yeast, which means the beer will end up much dryer (i.e. lower in sugars and sweetness) than a typical ale.
This is one of the reason’s sour beers are called “wine like.”
“Brettanomyces” actually means “British yeast” and was discovered by brewers trying to find out why their beer went bad.
The British have done their best to eliminate this sour character from all of the beers they brew. Which means a Birish IPA or Stout does not taste the way it did 150 years ago.
The Belgians have done the opposite and kept the “off” flavors that come from fermenting their beer in open fermenters and wooden barrels.
When the yeast and bacteria come from the air or the wood in a barrel it is called a “wild” beer, when the brewer specifically adds them in a controlled fashion, it will be a sour.
Recently, I attended the monthly “Beer School” tasting event at the Memphis Taproom (at 2331 E. Cumberland St.), this event takes place every first Wednesday of the month at noon and lets patrons get an inside look at the beer training the owners give to the staff.
This month’s even focused on sour beers made only with Brett.
As mentioned above, sour beers can be expensive, so it was an eye opener to have an inexpensive sour beer poured. This was the Green Flash Rayon Vert, available for around $5 a bottle at the bar or $9 a 4-pack over the bridge in New Jersey.
The beer has a sweet but vinegary aroma, it is dry up front, but finishes sweet.
We also tried the trappist beer Orval, the only trappist beer to be intentionally soured.
Overall, it was a perfectly balanced beer, it also benefits from aging - I think our bottles were at least two years old.
We also tried Ommegangs Biere De Mars.
I loved the aroma of this beer, but the flavor fell flat for me, it seemed thin and slightly sweet but without the complexities of the other two beers.
A wild fermented beer I recommend everyone try is the Rodenbach Grand Cru.
Its flavor can be pretty out there, with a strong sourness and vinegar, but it is a beer everyone should try once (or more than once if you really take a liking to it).
If you want to keep up to date on special events at Memphis Taproom, or be notified about the theme of the next Beer School, be sure to sign up for their mailing list at www.memphistaproom.com.
Tim Patton is a Fishtown resident, beer aficionado and brewer. His column is dedicated to showcasing everything that is great about enjoying beer in the riverwards. He can be contacted at firstname.lastname@example.org