Over the past couple of decades, awareness of “kettle-soured” beers and the methods involved have spread through the trade like Lactobacillus in fresh wort. What began as a niche method to attempt styles such as Berliner weisse and gose now flourishes as an important way to support the flavors of popular fruit beers.
If early attempts were unpredictable and often nasty, soured by a handful of grains or some yogurt, brewers have since shared and adopted an array of ways to consistently acidify wort on a tight schedule. Labs have been indispensable to this progression, studying and isolating acid-producing bacteria and yeast strains that can give brewers the sort of control they’re used to having over every other aspect of their brew day.
Here’s an overview of the growing variety of options.