Apologies if I missed the answer is it was posted here, but saurgut is essentially just a lactic fermented beer, right? Would a kettle-sour Berliner Weisse style beer that was inoculated with a handful of Pils malt be in the ballpark? I don't think I'd make saurgut just for the sake of saurgut, but if I had some lactic sour beer laying around I'd possibly consider adding some to my mash instead of lactic acid as a pH adjustment.