I'm struggling a bit with imperial units and also with mathematically converting DME into malt because I'm not used to using either but the 12 oz of acidulated malt in your
recipe don't sound excessive. If I have calculated accurately this comes to about 6% acidulated malt in the grist, and I have only recently tasted a red ale of a fellow homebrewer with 8% acidulated malt, and I could not detect any sourness. That was a darker and maltier beer though, so the acidulated malt may have come through more in your beer.
Having said all that, I also looked a bit into the resources I have on historical beer styles. There aren't any posts on this on my "home" forum hobbybrauer.de but I found a few links to old books and discussions, and in the
Krünitz Encyclopedia of 1775 there is a mention of Kottbusser. It's been very briefly described as a beer "very similar to the Broyhan but more warming to the stomach"
. The Broyhan (named after the inventor) in my understanding was a lightly soured beer, stems from the early 16th century and was also the predecessor of the Berliner Weiße, probably also Lichtenhainer and Gose. They all had (or have, they still exist) some lactobacillus-induced sourness, and as such using acidulated malt is probably the easiest way to replicate this if you don't want to engage in lacto fermentation.
It is certainly very interesting that the beer style goes back a very long way! The Broyhan (as its predecessor), according to Krünitz, was also brewed with various spices, such as clove, cinnamon, coriander and other spices I have never heard of let alone do I know their translation into English. Who knows how it evolved over the centuries though? It appears the records are thin on this point.
I definitely put this beer on my list of ideas, even though I'm not sure whether I will engage in lacto-induced fermentation. Your descriptions sound so tongue-tickling that I simply have to try, I guess.
It's quite fascinating that Randy Mosher has engaged in this beer style also. One of his recipes (Dick's Elixir Wheat Porter) was picked up by a German homebrewer, eventually a several-stage adaptation of the recipe ended up at Schneider brewery, and they produced one of their annual special beers from it. So it wouldn't be the first time that a long-forgotten beer style comes back here via the US!