Sour Power


One of the most intriguing trends in craft beer in the United States has been the emergence of sour beer styles. While these styles of beers feel relatively groundbreaking to us, beer producers in Germany and Belgium have been making them for a very long time. Before the sanitation practices of the current day, sour flavors in beer were common. Per usual, what makes sour beer production in the United States exciting is that we are not beholden to any particular style guidelines, but that doesn’t mean we don’t take inspiration from European expertise.

A great place to start telling the sour beer story through the Saint Arnold lens is Boiler Room – a German-style Berliner weisse we first released in 2014 and has been brought back for a limited time in six pack cans to-go at the Saint Arnold Beer Garden & Restaurant. A Berliner weisse is the ultimate refresher, with just the right amount of tartness to keep you coming back for another sip. The low alcohol content of the style also makes it perfect for a drinking session on a hot day.

So, what gives Boiler Room its characteristic tart flavor? This might not be the answer you expected – but it’s the introduction of bacteria to the wort. Specifically, lactcobacillus. Lactobacillus is a common bacteria found in several types of food: yogurt, cheese, sauerkraut, pickles, and many other fermented foods. Lactobacillus converts the sugar created during the mash into lactic acid. After we introduce the bacteria to the wort in the kettle and achieve our target pH, we boil to stop any further souring from taking place. This process is referred to as “kettle-souring” and allows breweries to stop their wort, and thus beer, from continuing to develop sour flavors (more on embracing that process later).

The boiled wort is transferred into a fermenter. For Raspberry AF, we add raspberry puree once it reaches a specific gravity. And not just a little raspberry puree, but 2300 lb each batch, which amounts to about ¾ lb per gallon. When it comes to a great place to start with sour beers, Boiler Room, Raspberry AF, and Berliner weisse are ideal.

We don’t always let the souring process stop developing in the kettle, though. As do breweries in Belgium when they make styles such as lambic, Flanders Red and Oud Bruin, often times we let wild yeast like Brettanomyces and bacteria like lactobacillus and pediococcus run wild in the confines of a wooden barrel. Making these beers is an artform that requires patience and willingness to part ways with beer that just didn’t develop the way you wanted it to. When you achieve the perfect balance of acidity, funk, beer character, barrel and sometimes fruit, it creates a symphony of flavor that you must taste to understand.

While it takes roughly two to six weeks for most of the beers we make at Saint Arnold, these funky and wild barrel aged beers we’ve released have taken anywhere from eight months to almost three years. These beers require patience as well as a sense of what the desired direction of the beer is intended to go. The brewer doesn’t necessarily “direct” the beer… he/she acts more as a chauffeur. We provide shelter (the barrel and temperature control), food (bacteria, wild yeast, sometimes fruit), and love (actual love). The end result isn’t always a positive, or even palatable one. Tasting these beers as they develop in the barrel is truly an incredible education on what these bacteria and yeast strains bring to the table.

We dump a fair amount of beer from our barrel room. However, the excitement that comes from a beer’s maturity and the time invested in waiting, and then blending, creates a deep bond with the beer and brewer… and hopefully the consumer as well. Blending is the act of taking several barrels, sometimes of the same beer and sometimes not, and creating a beer that is greater than the sum of its parts.

We’ve released a few barrel aged sour beers as of late, including a Raspberry Sour and a couple iterations of a barrel aged Wild Saison. Keep your eyes peeled for more releases in this category over time.

While not for everyone, sour beer provides an ever-expanding frontier of flavor that surprises and delights even the most veteran of craft beer drinkers. Start with a Boiler Room or Raspberry AF, and see where the journey takes you.


Published August 11, 2020