San Francisco sourdough gets its distinct tang from a wild yeast strain, Lactobacillus sanfranciscensis, first identified and named for the city's own Gold Rush-era bakeries.
A round loaf of tangy sourdough is hollowed out and filled with hot, creamy clam chowder, eaten by scooping out the bread as you go until the bowl itself is gone. Walk-up stands along Fisherman's Wharf hand it over in a paper wrap for eating on the pier.
Philly Cheesesteak