To make a biga
2 1/2cups (11.25 oz) unbleached bread flour
1/2 t (.055 oz) instant yeast
3/4-1 cup (7 or 8 oz) water
Make sure your dough is tacky, not sticky. Knead for 4-6 minutes (or use a dough hook on medium for 4 minutes), until the dough is soft and pliable.
Coat a bowl with oil, dump in the dough, cover with plastic wrap, and allow to ferment at room temperature for 2-4 hours. Allow it to nearly double in size.
Remove from the bowl and knead lightly to degas. At this point, you can either use the biga in a recipe, or cover again and leave in the fridge overnight, which further develops the flavor. (Overnight is recommended.)