200grams(7 ounces / ¾ cup plus 2 tablespoons) very warm water (105º to 115ºF)
⅛teaspoonactive dry yeast
227grams(8 ounces / 1 ½ cups plus 2 tablespoons) unbleached all-purpose flour
In a medium bowl, mix the warm water and yeast together and stir to dissolve the yeast. Add the flour and stir vigorously with a wooden spoon for 1 to 2 minutes, until a smooth, somewhat elastic batter has formed. The batter will be fairly thick and stretchy; it gets softer and more elastic after it has risen. Scrape the biga into the container, mark the height of the starter and the time on a piece of tape on the side of the container so you can see how much it rises, and cover the container with plastic wrap.
Let it rise at room temperature (75º to 78ºF) for 6 to 8 hours. Or let it rise for 1 hour at room temperature, then chill it in the refrigerator for 8 hours or overnight. Remove it from the refrigerator and let it sit at room temperature for 3 to 4 hours to warm up and become active before use. Biga should more than double in volume. If you use the starter while it’s still cold from the refrigerator, be sure to compensate for the cold temperature by using warm water (85ºF to 90ºF) in your dough, instead of the cool water specified in the recipe. Use the starter while it is still bubbling up, but before it starts to deflate.