This one:
https://sourdo.com/product/original-san-francisco-culture/
And this one is extra sour:
https://sourdo.com/product/austria-culture/
I grew up in Oakland and Castro Valley. In CV we had a Columbo and Francisco's bakery up the street and would get fresh baked or day old bread.
Lots of memories going to Fisherman's Wharf, GG Park and Kezar and Warren for football. Those were the days of Y.A. Tittle, John Brodie, Daryl Lamonica and George Blanda!