That Wonderful San Fransisco Sourdrough Taste!!!
I've been trying for a year...of daily starter feedings, ineffectually... and came across SECRET_INGREDIENT's post that included research from Karel Kulp and Klaus Lorenz research on Lactobacillus sanfranciscensis (LBsf) entitled "70 Pounds of Sponge Later". I think it implies that LBsf thrives at 32-33C (89.6-91.4F), and all other Lactcobacillus forms (probably) don't.
So I've kept my starter culture at 90F for the last coupe of weeks, and noticed a remarkable difference, very similar to the SF tangy taste. I assume that other strains of Lactobacillus don't thrive at this high temp, and LBsf does, and is responsible for this unique taste. My proofing includes 4 hrs at 70F, 10 hrs at 60F, then 3 hrs at 90F, then into the oven for 30 min at 450F (or 190F internal temp).
I've been keeping my starter culture in an ice chest regulated by a Zilla Reptile temperature contoller plugged into a 60 watt incandescent bulb. I use a completely independent temp probe to moniter temp externally. The last 3 hrs of proofing are done in the proofing box.
So far I've had tastes very much like San Fransisco Sourdough. It would make sense, considering that "Sourdoughs" (early US western settlers, or SF 49'ers NFL mascot), kept their bread levin cultures under their shirts on necklaces, or waistbands, between baking projects at slightly lower than body temperatures.
I hope this helps anyone trying to duplicate SF Sourdough-like-tastes, since the industry has had little regard for my inquiries into the subject...sorry frigg'in bastards...