Understanding Bread Fermentation — Wild, Commercial, and Everything In Between

Fermentation is the single most important process in breadmaking. It's what transforms a lump of flour and water into something with flavour, texture, and character — and the choices a baker makes about fermentation define the bread they produce.

Wild vs Commercial Yeast

Commercial baker's yeast (Saccharomyces cerevisiae) is a single, fast-acting strain that raises bread quickly and predictably. A sourdough starter is a complex ecosystem of wild yeasts and lactobacillus bacteria, producing a wider range of flavours and a more complex crumb — but requiring more time and skill.

Why Time Matters

During fermentation, enzymes break down starches into sugars, producing flavour. Longer fermentation means more flavour development, better digestibility, and a more open crumb. A 24-hour cold ferment produces a fundamentally different bread than a 2-hour warm proof.

Cold Retardation

Many artisan bakers retard (slow down) their dough in the fridge overnight. The cold temperature slows yeast activity but allows enzymatic activity to continue, deepening flavour without over-proofing.

Reading the Signs

A well-fermented dough is puffy, jiggly, and slightly domed. Under-fermented dough is dense and tight; over-fermented dough is slack, sticky, and acidic. Learning to read these signs by touch is the most important skill in bread baking.