Intro to Sours: The Tart, Funky World of Wild Fermented Beers
- Andrew Marr
- Jun 6
- 2 min read
Sour beer is one of the most exciting corners of the craft world. Bright, tangy, and often fruity, sours offer a completely different experience than your typical IPA or lager.
But how do brewers make beer sour on purpose—and why would they want to? Let’s explore.
The Science of Sour
Most beers are fermented with Saccharomyces yeast, which produces alcohol and carbon dioxide. But sour beers add other microbes:
Lactobacillus → lactic acid = tart, clean sourness
Pediococcus → lactic acid + complexity over time
Brettanomyces (Brett) → funky, earthy, fruity flavors
These microbes lower pH and create acidity, giving sour beers their signature zing.
Kettle Souring
A popular modern method is kettle souring:
The brewer makes wort (unfermented beer).
Lactobacillus is added and held warm (95–115°F) for 1–3 days.
Once desired tartness is reached, the wort is boiled (killing bacteria), then fermented normally.
Kettle sours (like Berliner Weisse or Gose) are fast, consistent, and bright.
Mixed Fermentation & Barrel Aging
For deeper complexity, some brewers use mixed fermentation:
The beer is inoculated with multiple yeast and bacteria strains.
It’s aged for months (or years) in stainless or oak barrels.
Brett and bacteria evolve flavors over time, creating earthy funk, vinous notes, and layers of acidity.
Styles like Lambic, Flanders Red, and American Wild Ales showcase this traditional method.
Explore the Sour Side
If you’re new to sours, start with approachable kettle sours. Then work your way toward mixed-fermentation beers for a more adventurous ride.
Use your Craft & Brew Passport to seek out NJ breweries making sours—many offer small-batch releases that disappear fast. Don’t be afraid of a little pucker. 🍋
