Sourdough Bread
levain (French term for the culture and the bread) · pain au levain
Sourdough is leavened by a live culture of wild yeasts and lactic acid bacteria rather than commercial yeast. The fermentation produces lactic and acetic acids that give the bread its characteristic tang, alongside a complex flavour from the extended fermentation (often 12–24 hours for a retarded cold dough). The same acids partially break down phytic acid in the grain, improving the bioavailability of the minerals in the bread — a distinction that matters if bread is a significant part of the diet.
Complex, slightly tangy from lactic and acetic acids, with a deep, slightly caramelised crust from Maillard browning. The crumb flavour varies from mild (short fermentation, more lactic) to distinctly sour (long cold fermentation, more acetic).
An open, irregular crumb with large air bubbles from the wild yeast fermentation. The crust should be hard and shattering when tapped. The crumb is chewy and slightly elastic. The balance between crust hardness and crumb tenderness distinguishes good from great sourdough.
Best consumed on the day of baking. After 24 hours, the crumb begins to stale. Store cut-side down on a board (not in a bag, which traps moisture and softens the crust). Freeze well-wrapped slices for up to 2 months — toast directly from frozen.
Slice with a serrated bread knife using a sawing motion (pressing down compresses the crumb). For toast: thick-sliced, in a toaster or under a grill. For panzanella, ribollita and bread-based dishes: use day-old sourdough that has begun to stale. Drizzle with olive oil and rub with a cut garlic clove while still warm from the toaster.