1Make sourdough starter at least 1 week before making bread. In large glass bowl, dissolve 1 1/2 teaspoons yeast in warm water. Stir in 3 cups flour and 4 teaspoons sugar. Beat with electric mixer on medium speed about 1 minute or until smooth. Cover loosely; let stand at room temperature about 1 week or until mixture is bubbly and has a sour aroma. Transfer to 2-quart or larger nonmetal bowl. Cover tightly; refrigerate until ready to use.
2Use sourdough starter once a week or stir in 1 teaspoon sugar. After using starter, replenish it by stirring in 3/4 cup all-purpose flour, 3/4 cup water and 1 teaspoon sugar until smooth. Cover loosely; let stand in warm place at least 1 day until bubbly. Cover tightly; refrigerate until ready to use. To use, stir cold starter; measure cold starter, and let stand until room temperature (starter will expand as it warms up).
3Measure 1 cup of the sourdough starter and all remaining bread ingredients carefully, placing in bread machine pan in the order recommended by the manufacturer.
4Select Basic/White cycle. Use Medium or Light crust color. Do not use delay cycle. (Total time will vary with appliance and setting.) Remove baked bread from pan; cool on cooling rack.