Poolish

Poolish is a liquid pre-ferment (pré-fermentation liquide) of Polish origin — hence the name — introduced to French boulangerie in the 1840s by Viennese bakers and subsequently adopted as a cornerstone technique of the French breadmaking tradition. A poolish is simply equal weights of flour and water (100% hydration) mixed with a small quantity of commercial yeast and left to ferment for 2-16 hours before incorporation into the final dough. The yeast quantity is inversely proportional to the fermentation time: 0.1% of flour weight for a 16-hour overnight poolish, 0.3% for an 8-hour poolish, or 1% for a 2-3 hour express poolish. The mathematics of timing allows the baker to prepare the poolish the previous evening and have it perfectly ripe the following morning. A poolish is ready when it has approximately tripled in volume, the surface shows a slight concavity (beginning to recede from its peak), and a network of fine bubbles is visible across the top — this indicates that the yeast has consumed most of the available sugars and the poolish has reached maximum flavour development without over-fermentation. The poolish typically represents 30-50% of the total flour in the final recipe. Its contributions to the finished bread are profound: the extended fermentation develops organic acids and flavour precursors that short-fermented straight doughs cannot match, the pre-fermented flour requires less mechanical mixing (reducing oxidation and preserving flavour), the high hydration promotes enzymatic activity that improves crust colour and crumb extensibility, and the accumulated alcohol contributes to oven spring and crust blistering. Poolish is the preferred pre-ferment for baguettes de tradition among many French artisan bakers because it enhances flavour and extensibility without the acidity of levain — producing bread with a sweet, wheaty, slightly nutty character rather than the tang of sourdough. The technique bridges the gap between the convenience of commercial yeast and the flavour complexity of long fermentation.

• Italian biga (stiffer pre-ferment)
• Austrian Vorteig
• American sponge method