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.