16 Dec #JeremySays – Kettle Souring
Kettle sours are all the rage nowadays. It’s a great way to get a one-dimensional lactic souring on the hot side. You can do this with any beer, but it’s typical in Berliner Weiss and plays well with certain hops in an IPA.
When you build your grain bill you can add 1-2% acid malt to get the pH below 4.5. This will inhibit wild yeast growth that can produce butyric acid during the souring process. After you finish lautering, and have your full wort volume in your kettle, then immediately chill to 115F, for more funk add a handful of grain dust, or boil to sanitize then chill for a cleaner flavor. Then pitch your lactobacillus delbrueckii and blanket the top of your kettle with CO2. Lacto is anaerobic so you want to keep oxygen away. Keep it as close to pitching temp as possible for the next 24-36 hours. At this point you should have a pH of around 3.3-3.7 and a good amount of funk. Then you can boil, chill, and ferment the beer. Berliner is a great blank slate for fruit and spice additions! Cheers!