They are actually famous for good sourdough bread.

French bakers brought sourdough techniques to Northern California during the California Gold Rush, and it remains a part of the culture of San Francisco today. The nickname remains in "Sourdough Sam", the mascot of the San Francisco 49ers. Sourdough has long been associated with the 1849 gold prospectors, though they were more likely to make bread with commercial yeast or baking soda.[7] The "celebrated"[1] San Francisco sourdough is a white bread characterized by a pronounced sourness, and indeed the strain of lactobacillus in sourdough starters is named Lactobacillus sanfranciscensis, alongside the sourdough yeast Candida milleri found in the same cultures.

https://en.m.wikipedia.org/wiki/Sourdough

By Serious Eats[0], founded by former New York Times food editor Ed Levine. Also by the BBC[1]. Arsicault Bakery in SF was named the best bakery in America by Bon Appetit. Tartine Bakery is a James Beard winner.

[0] http://www.seriouseats.com/2013/08/taste-test-the-best-sourd...

[1] http://www.bbc.com/travel/story/20131121-flour-power-in-san-...

This is seriously not meant to be a snark at all but I've only ever heard it from people in SF.