8 to 16 hours ahead or simply: the night before.

Sponge or Poolish Starter
1 cup water, preferably spring water
1/2 teaspoon dry yeast
1 1/4 cups unbleached bread flour or organic white bread flour
2 tablespoons organic whole-wheat flour
2 tablespoons organic rye flour

Dough
(all of) starter
1 cup water, preferably spring water
2 1/2 teaspoons salt
1 tablespoon sugar
1/2 teaspoon malt powder or syrup (optional - see home brewing supply or health food stores)
1/2 teaspoon yeast
3 3/4 to 4 cups unbleached bread flour