Overview

San Francisco–style sourdough is a naturally leavened bread characterised by pronounced acidity and distinctive flavour. It is produced using a stable microbial starter culture maintained through backslopping.

Raw Materials

  • Wheat flour
  • Water
  • Sourdough starter culture

Fermentation Process

Flour and water are mixed with a starter culture and allowed to ferment over several hours to days. The dough undergoes repeated refreshment cycles, followed by baking to produce leavened bread.

Microbial Ecology

Fermentation is dominated by:

  • Lactobacillus sanfranciscensis
  • Saccharomyces spp.

These microorganisms coexist symbiotically, producing organic acids and carbon dioxide.

Functional and Nutritional Aspects

  • Improved mineral bioavailability
  • Organic acid production contributes to flavour
  • Extended shelf-life compared to yeast-only bread

Cultural Significance

San Francisco sourdough is a regional food identity and a well-studied model system in cereal fermentation microbiology.

References

  1. De Vuyst, L., & Neysens, P. (2005). The sourdough microflora. Food Microbiology, 22(4), 293–302.
  2. Hammes, W. P., & Gänzle, M. G. (1998). Sourdough breads. Food Microbiology, 15, 189–197.
  3. Steinkraus, K. H. (1996). Handbook of Indigenous Fermented Foods. Marcel Dekker.