But like other beer styles, there’s more history behind this diverse beer style than just what meets the palate. First though, one might ask, what makes a beer sour?

As yeast eats the sugars that have broken down in the mash, bacteria is produced which creates the telltale sour characteristic in taste and aroma. Your sour beer actually has a little creature in common with yogurt and sauerkraut, Lactobacillus and Pediococcus. Lactobacillus, perhaps the more prevalent of the two bacteria in beer, is the bacteria whose hard work turns milk into yogurt. Pediococcus, which in beer is less common, makes our cabbage into sauerkraut. Often Lactobacillus is easy to identify within one quick whiff of your beer; if you smell a tangy yogurt smell, that’s Lactobacillus at work.

At one point or other, much of all beer drank in the early days of beer’s long history was somewhat sour. With variations among ingredients, hygiene, brewing practices, and ultimately storage, all beer was susceptible to bacteria which produces souring characteristics. Even today in most beer, sourness is a sign of spoilage and a good reason to send your beer back.

Despite the unwanted sourness in most beer styles, one country harnessed this bacteria and learned to work with the nuances, creating a number of archetypes that are endlessly exciting and timeless-Belgium.

Belgian Sours

Belgian beers have long dominated the sour market. For a drinker wanting to expose their tongue to classic sours, the Belgian sours from the area surrounding Brussels and in North Flanders are a great way to start; Geuze, Lambic, Flanders Red Ale, and Oud Bruin are the most famous of Belgian sours. Lambic, (and therefore Gueze, since it’s a blend of Lambics that undergo a secondary bottle fermentation), are beers that are powered by wild yeasts. But all sours are not necessarily products of spontaneous fermentation.

The beers of master Lambic blender Boone are a fantastic introduction into this complex style. Geuze Oude Boone and Mariage Parfait are wonderfully full bodied sours, complex in both aroma and taste. Oude Boone starts with an extremely yogurt-like aroma, pungent and almost like old socks. Mouth puckering, it’s a fantastic example of lactobacillus at its best.

Kriek, a spontaneously fermented lambic made with cherries, is originally from the area surrounding Brussels. Again, we really like Boone’s Kriek, which uses 400 grams of cherries per bottle. The cherries, left in for a period of months, feed the yeast in such a way that all the sugar is fermented out of the beer, leaving it wonderfully dry and tart. A pleasant surprise for those who don’t like to taste fruit in beer.

Brouwerij Alvinne is a notable contemporary brewery specializing in Flemish Sour Ales, and they do remarkable things with wild yeasts and barrel aging. They have a lovely sour collection that really pushes the limits of your expectations and ideas of what beer is capable of. We found their beers to be a real adventure; Chain Reaction was just completely funky, extremely mouth puckering, and full of earthiness. Wild West, which is aged in oak barrels is considerably smoother, has a lingering sour finish and slight smokiness.

German Sours

Our fellow beer guzzling neighbors to the West also have a rich history of sour beers, which are actually at the center of what microbreweries are trying to emulate today. Berliner Weisse, by far the style that has had the most influence on Czech microbreweries, goes back to 16th century Northern Germany, but its namesake Berlin gave it fame in the 1900s. A style that just a few years ago was almost extinct, it has come back with gusto. Originally served with a kind of fruit syrup to off set the mouth puckering reaction, today’s Berliner Weisse often come fruit infused instead.

Another sour who calls Germany home, and perhaps my personal favorite, is Gose. The origins of this lesser known sour lie in the countryside around the town of Goslar (close to Leipzig), where a unique salty water source gave this sour beer its telltale salty feature. Like Berliner Weisse, Gose is a low alcohol beer, usually about 3% abv.

The New Czech Sours

Quite a few remarkable sours can be found on the Czech microbrew scene. Most are brewed in the Berliner Weisse fashion, about 3% abv., and quite often fruit infused. Here’s a rundown of some sours we’ve tried (and we’ve been drinking them for a while).

Nina-This is a line of Berliner Weisse sours brewed by Clock, one of our favorite microbreweries. We’ve tried the Raspberry and the basic without fruit Nina. We enjoyed the Raspberry Nina, which had a wonderfully fresh and natural aroma of fresh raspberries. It’s gently tart, light in body, and supremely refreshing. The tartness especially hits the top of your mouth, adding a sprite tingling sensation through to the aftertaste, which isn’t particularly dry, but more about the fresh raspberry taste which once again steals the show. An excellent sour despite being on the verge of too fruity for our tastes, and well worth a try and the extra money.  

The version of Nina without fruit is wonderfully tart and dry and extremely crisp, and no doubt able to quench some intense thirst. There’s also a highly coveted Blueberry Nina, which sadly was gone too fast for us to get our hands on a bottle.

Raven-Their Kiwi Berliner Weisse is by far our favorite. The fruitiness is subtle, which we prefer. More mildly sour than some, it’s still dry and supremely refreshing, with a hint of green tea. Supposedly they have more editions made with different fruit coming out, but we’ve yet to find one.

Sibeeria - Sibeeria brews a Pilsner Weisse, which sadly, tastes just as bland and boring as the former Beer Lab’s Pilsner Weisse (the same people are behind this flying brewery). This is a very one dimensional, flat, and disappointing beer, which also isn’t that sour either.

To find sours in Prague, check out bars like Illegal Bar, Beer Geek, and Bad Flash. Good beers shops that regularly stock sours are Pivni Galerie in Vrsovice, Beer Geek, and Illegal Bar.