Combine all ingredients except grapes; mix well.
Gently mix in grapes. Oil and flour the bottoms of four 12 X 6 X 5 cm loaf pans. Pour one-fourth of batter into each pan. Bake at 180 C 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.
Recipe supplied courtesy of Grapes from California