We're heading to Mountainview Brewing Co. in Hope BC to see how they brew an experimental batch of blackberry kettle sour. The wort is soured in the kettle with lactobacillus bacteria. The lactobacillus bacteria consume the sugars in the wort and produce lactic acid. This lactic acid lowers the pH of the wort, making it sour. Blackberry puree is added during secondary fermentation to give a juicy kick to this tart beer. So let's go see how it is made.