Update - this Ketwurst stall is no longer trading. If you want to try Ketwurst in Berlin, head for Alain Snack at Schönhauser Allee 116A, which has been selling Ketwurst since the GDR days. A full write-up may follow eventually!
Head down to the U6 platform at Friedrichstraße station and you might notice this little hot dog stand. There's something a bit more unusual on offer here, though. Ladies and gentlemen, presenting...the Ketwurst!
Back in the late 70s in the GDR, a search for new fast foods to sell to visitors at Alexanderplatz led food researchers to come up with a combination of a sausage, ketchup and a bread roll...sounds just like a hot dog, you say? Well...almost.
Not happy to serve up American-style hot dogs in the heart of communist East Berlin, the boffins at the Rationalisierungs- und Forschungszentrum Gaststätten (that is, the streamlining and research centre for restaurants) created their own, more ideologically acceptable, version. The name came from combining the words Ketchup and Wurst, in typical East German style (a lot of words came about that way - MuFuTi from Multifunktionstisch, a multi function table, for example).
To make a Ketwurst, a long bread roll is placed on a heated spike, making a hole in one end. A bockwurst-type sausage, heated in water, is then dipped in tomato sauce, which is dripped into the hole before the sausage goes in after it.
Thomas Stürmer has been growing his empire of Ketwurst stands since 2003, under the name Original Ketwurst. Frustrated by the disappearance of what he felt was authentic Ketwurst from the streets of Berlin (there are other places selling it), he dug out an old recipe and took to the streets to sell the resurrected snack. The secret to his ketwurst is in the details - the roll is a more crusty type than the typical hot dog bun and the sauce is a more tangy, spicy sauce than ordinary ketchup (he keeps tight lipped about how it's made, but I suspect there's mustard in it, amongst other things). An East Berlin butcher makes the sausages and an East Berlin bakery bakes the rolls.
Does it taste the way they did back in the GDR? That I don't know. Does it taste good? It sure does...at least if you like this sort of thing! Those after a fine dining experience probably won't find munching on Ketwurst in Friedrichstraße station very satisfying. For fans of things involving sausages and tomato sauce, though, it's well worth a go!