I plan to make a Berliner Weiss, my first. I'm interested to hear opinions about the ideal pH to lower the wort to before souring, and also the ideal temperature for the souring step. I'm planning to do the souring in a corny keg (with some unmilled base malt), purged of O2, and sealed with just enough CO2 pressure to keep the lid sealed, unless there's a reason not to do it that way. TIA!
I'd use lactic acid, and lower the pH before souring to around 4.8-4.9 probably. I find it helps ward off "the yuck". Temp wise, I find it a toss up. Honestly, warmer will speed it up, but if you time table is like mine, I'm only free on the weekends to brew, and don't have the desire to fire the kettle up at 7 PM on a Wed. evening. Room temp, or even something around 75-80 would work, and take probably a week in my experience. I don't speed it up, and like the level of sour in the end. Around 3.2 pH is where I like to be. Atleast under 3.4 . I don't think under pressure should cause an issue, I've never done it, but I don't see what it would really affect since it's such a short time. I think the purged space would be ideal, especially when you sample, you can purge the keg headspace out easy enough. Keep it 80, and I think you'd have something sour enough in 5 days. Hotter= shorter, cooler=longer usually.
I did a series of about 10 sour mash beers a couple years ago, but became sensitive to the "sour mash flavor" and haven't done one in about a year. I used to lower the pH to </= 4.5 to keep aerobes at bay (along with a THOROUGH CO2 flush). I also kept the sour mash temp high (115-120) to suppress Clostridium sp. If non-Lactobacillus microorganisms are adequately suppressed, a soured mash should have no off aromas and should smell cleanly lactic (mine usually smelled like apple cider). My favorite BWs were ones with post-fermentation additives. Heavy-handed dry hopping/keg hopping with American hops make a nice little beer.
I've heard that 4.5 is an ideal ph pre souring (chad yakobson). Doing it in a keg is fantastic as well to ensure no/limited oxygen. If your pitching a clean sacch strain i reccomend pitching that at around a ph of 4 to ensure a more full attenuation. If your pitching Brett (trois would be my choice) I think you can wait till a ph of 3.6-3.8 to pitch. I pitched a kolsch yeast into a 3.4 ph beer and it hated it, Brett Custersianus did well tho. Edit. I agree with @FATC1TY on temps and time tables.
Very good points I didn't post. If you are using a sach strain, I've only used Kolsch and US05, I think a german ale would be pretty nice myself for the next time. Only problem is this.. If you boil after souring, then you will struggle with the yeast as the beer will have a low pH after boiling. I think a plus to the sour wort method is keeping everything away from the lacto on the cold side. Problem is you work for it with the yeast selection and pitching. Lager like pitching amounts for that low pH. If boiling it, and souring it after the boil, then yes.. pitch sach after giving the lacto a head start. Ferment out, and warm it to sour it to your level.
I've done a sour wort berliner twice. Both were kept around 100F in the kettle with grain for about 24hrs before boiling. The first went to 3.5 and was near perfect while the second went to 3.2 and gave the yeast trouble. Fermented with kolsch yeast both times.
Not sure what pH I was at last time, but I've done successful sour mashes(in a purged keg) with roughly 10% acid malt into the base recipe. I added the acid malt after the main mash converted, pasteurized, cooled to 120 and racked to the keg.
Anyone have a favorite water profile for a Berliner? I'm talking about mineral content (aside from pH considerations). TIA!
I don't do much with any of my sour beers. ~100 PPM chloride wouldn't hurt to add a little mouthfeel considering the low OG/FG. Other than a bit of calcium for yeast health I'd keep everything low. You can always dose minerals to taste in the soured beer to see how they influence your perception of it!
