What is biga?

An Italian-style stiff pre-ferment, roughly 50-60% hydration (not equal parts flour and water — that would be a poolish). Mixed with a small amount of yeast (~0.1-0.3% of the biga's flour) and rested 12-16 hours at room temperature until tripled in volume and webbed with bubbles. The next day, the biga goes into the final dough as a pre-fermented chunk of flour. The stiff hydration is the defining difference: where poolish develops sharp, slightly tangy flavors, biga develops gentler nutty and yeasty notes. The slower fermentation also produces stronger gluten, which is why ciabatta and many Italian artisan breads use a biga rather than a poolish — the strong gluten network supports the recipe's characteristic high hydration without collapsing.