In the bowl of an electric mixer, combine 4 cups of bread flour, 1 cup (125gr) of whole wheat flour, yeast, and salt. Using the flat stirring blade of the mixer, turn the mixer on and gradually pour in small amounts of the sourdough starter and water alternately until all has been added. Change the flat mixing blade to the dough hook and add small amounts of the remaining flour until all is incorporated. The dough should be firm and fleshy, not sticky. If necessary, add more flour a spoonful at a time while the mixer kneads. Knead the dough for a total of 4 minutes on medium low speed. You can add up to an extra ½ cup (62gr) of bread flour if necessary.

Remove the dough from the mixer. If it is still sticky, hand knead it on a liberally floured surface for another minute to incorporate the right amount of flour. The dough should be bouncy and firm, but not hard. (The right texture takes practice, but you will get the hang of it!)

Coat the interior of a large bowl with olive oil. Place the kneaded dough in the bowl, and turn 1-2 times to coat the dough with olive oil. Cover with a towel, and allow to rise in a warm place for 1 hour, until doubled in bulk.

Coat the interior of 2 medium loaf pans 9″x5″x2.75″ (23cmx12.7cmx7cm) with olive oil or food spray. Punch down the dough, allow to rest for 5 minutes, and then shape into two loaf, placing the dough in the prepared pans. Allow the loaves to rise in a warm place for another hour, until they are doubled in bulk. Preheat your oven to 400°F (204°C) for at least 15 minutes before the end of the rise time.

Once the loaves have fully risen, place in the preheated oven and bake for 25-30 minutes. Bread is fully cooked when it sound hollow when crust is tapped. Remove the bread from the pans after 5 minutes of cooling, and then allow to cool completely before slicing.