I brewed a kettle-soured Berliner Weisse with an OG of 1.034. After two weeks fermenting at around 70 (raised to 72 at the end) with a packet of Safale US-05, it got down to 1.014, apparent attenuation of 58%. The malt bill is also about 7% acidulated malt. Mash temp was low, about 148. Souring was done in the kettle with some unmilled malt, insulated, kept at 100-110 for about 48 hours.

I've read that that the low pH can lead to low attenuation like this. I'm wondering - what are normal attenuation rates for ale yeast in sour worts with high-acid/low-pH? I've also heard of people hitting attenuation in the 80s with Berliners as well.

1 Answer 1


I used to mash-in my berliner at 150 F, and then just let it cool down to 120 F or so. From there my souring process was pretty much identical to yours. But, I usually pitched straight L delbruckii, with a followup pitch of WLP630 or some other ale yeast(s). With multiple organisms at work, there's more potential for attenuation, and I would always see the equivalent of 80% - dry enough that we didn't worry about it, to say the least.

One trick I always liked: throw in an active starter of champagne yeast, and let it run. This will get your berliner dry!

I don't have much experience with US-05 - Fermentis claims it'll do 81% apparent attenuation, but I understand that in practice 70% is more in the range of reasonable.

One observation: did you take a pH reading? Not knowing the exact mash bill/story, you might just be assuming your wort is/was highly acidic, though with that much acid malt I guess it's probably the case!

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.