Whisk the yeast into the water. Allow to sit for about three minutes. Add the flour, mixing for another three minutes. Place in a nonreactive bowl and cover. Allow to sit in a draft-free spot until it rises and gets thick and sticky. This will take about eight hours.
Use a spoon to stir the sponge down before measuring for use in a bread.
Once risen, refrigerate for up to three days. Allow to come to room temperature before using. If it goes beyond three days, discard all but 1 cup of the sponge and make the recipe, adding the reserved sponge with the flour. Stir for two or three minutes before using.
For all of the breads based upon this sponge, allow two days since the doughs require overnight refrigeration.
For the best results, use as little of the kneading flour as possible.
To allow yourself to slide the loaves into the oven, form them on a baking sheet without sides or on the bottom of one with sides that is turned upside-down.
If you do not have a stone or tiles, bake directly on the baking sheet(s) upon which you formed the loaves (be sure to use either cornmeal or parchment between the dough and the sheet).
All of the breads based upon the sponge can be frozen for up to two weeks. Don't freeze until the bread has cooled thoroughly - then wrap in foil and freeze. When ready to use, thaw them, still wrapped, at room temperature overnight. Then, unwrap and warm at 350 degrees for 5 or 10 minutes. Alternatively, you could warm the frozen and wrapped loaves at 300 for 35 to 40 minutes.