Mix water with 1 cup cereal. Sift flour with baking soda. In a large bowl, beat butter until creamy. Add sugar 1/2 cup at a time, beating after each addition. Blend in eggs, one at a time, beating well after each addition. Scrape sides of bowl often. Stir in flour mixture 1/2 cup at a time, alternating with butter/sour milk, added 1/2 cup at a time also. Stir in soaked bran and the remaining bran cereal. Cover and store in refrigerator at least 6 hours before baking. To bake muffins, heat oven to 400 degrees F. Grease 2 1/2-inch Muffin Cups. Stir batter gently. Fill each muffin cup with about 1/4 c batter. Bake about 20 minutes, or until nicely browned. Remove from pan and serve hot with butter. Makes 6 cups batter or about 24 2 1/2-inch muffins.