Combine all ingredients except grapes; mix well. Gently mix in grapes. Oil and flour the bottoms of four 5 X 2-1/2 X 2-1/4-inch loaf pans. Pour one-fourth of batter into each pan. Bake at 350ºF for 40 to 45 minutes or until wooden pick inserted near center comes out clean. Cool 5 minutes. Turn out onto wire rack and cool completely before slicing. Makes 4 loaves.