Instructions: Place the yeast in a small bowl and add 1/2 teaspoon of the sugar and 1/4 cup of the water. (If using active dry yeast, increase the temperature of the water to 110 degrees.) Stir until the yeast is dissolved. Set aside in a draft-free place until covered with bubbles, 10 to 20 minutes. (If there are no bubbles, the yeast is too old to be useful.)

In a large bowl, combine the yeast mixture, 3 cups of the bread flour, 2 tablespoons of the remaining sugar, the remaining 2 3/4 cups water and the optional malt, deli rye flavor and citric acid, if using. Whisk until very smooth, about 100 strokes; set aside.

In a very large bowl, whisk together the remaining 3 cups of the bread flour, the rye flour, the remaining 2 1/2 teaspoons sugar, the caraway seeds and salt. Gently scoop the flour mixture onto the reserved yeast mixture to form a blanket. Cover with plastic wrap and set aside at room temperature until the dough has risen considerably, 4 to 5 hours (may refrigerate for as long as overnight).

Add the oil to the dough and, using a wooden spoon, mix to combine, adding flour or water as needed to form a soft dough. On a lightly floured surface, knead the dough, adding flour as necessary to keep it from sticking to the surface, until it is smooth and elastic, about 10 minutes. The dough should jump back when pressed with a fingertip. Form the dough into a ball. Lightly oil a large bowl. Place the dough in the bowl, turn to coat with the oil, cover tightly with plastic wrap or a damp towel and set aside to rise until doubled in bulk, 1 to 2 hours (the dough will rise more slowly in a cold room).

Using your fist, punch the dough to deflate it. On a lightly floured surface, knead the dough briefly. Form the dough into a ball, return it to the bowl, cover and set aside to rise a third time for 45 minutes.

Sprinkle a baking sheet with cornmeal.

To shape the dough, roll it into an 8-inch ball or 2 smaller balls and place the dough on the cornmeal-sprinkled baking sheet. Cover with a large inverted bowl or plastic wrap that has been oiled. Set aside to rise until doubled in bulk, 60 to 75 minutes.

A little more than halfway through the final rising, adjust the oven rack to the lowest position. Place a second baking sheet on the rack. Preheat the oven to 450 F.

When the dough has risen, using a sharp knife, slash the top of the loaf twice in 1 direction about 6 inches apart, then slice again with 2 slashes perpendicular to the first set.

Carefully slide the dough directly onto the preheated baking sheet and bake the bread for 15 minutes. Reduce the temperature to 400 F and continue to bake for 50 to 65 minutes (34 to 40 minutes for the 2 small breads), until the bread is golden brown and sounds hollow when lightly tapped.

Transfer the baking sheet to a wire rack to cool slightly. Baked bread stays warm for 2 hours after baking.

* Note: Barley malt, also known as diastatic malt powder, is available locally at many grocery stores or by mail order from King Arthurs Flour (call 800-827-6836 or see www.kingarthurflour.com). Deli rye flavor and citric acid (or "sour salt") is also available from King Arthurs Flour. Citric acid is available at some grocery stores.

Yield: (Makes 1 loaf) This makes 1 very large loaf or 2 smaller ones.

NOTES : Using fresh yeast will cause the bread to rise more quickly. Preheating the baking sheet makes the bread begin to rise immediately upon contact; this results in the bread holding its shape and attaining the highest rise.

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