Sourdough Bread

Global — the earliest leavened bread evidence dates to ancient Egypt (c. 3000 BCE); wild yeast fermentation is the original bread technology; sourdough declined in the 20th century with commercial yeast but experienced a global revival from the 1970s (San Francisco sourdough as the contemporary reference point) and was dramatically accelerated by the COVID-19 pandemic home baking movement of 2020

The world's oldest leavened bread — flour, water, salt, and wild yeast cultivated in a living starter of flour and water — is simultaneously the simplest and most technically demanding bread in the baker's repertoire. The starter (levain, chef, or madre) is a community of wild Saccharomyces cerevisiae yeasts and Lactobacillus bacteria that produce both carbon dioxide (for leavening) and lactic and acetic acids (for flavour): the balance of these two acids — controlled by hydration, temperature, and timing — determines whether the final loaf is mildly tangy (warm, wet environment, short ferment) or aggressively sour (cool, dry environment, long ferment). The techniques of bulk fermentation, autolyse, lamination or stretch-and-fold, pre-shaping, cold retard, and scoring have been codified by the contemporary sourdough movement but represent refinements of traditions practiced by bakers in San Francisco, Germany, and the Middle East for millennia.

Eaten warm from the oven with cultured butter; as the base for avocado toast, tartines, and open sandwiches; the flavour spectrum from mild San Francisco-style lactic tang to aggressively sour German-style Roggensauerteig (rye sourdough) represents the full range; paired with cheese, charcuterie, or as the bread for a ploughman's lunch