Dissolve yeast in 1 cup warm water.

Mix yeast mixture, sourdough starter, honey, salt, and shortening with 3 cups of whole wheat flour.

Gradually add more flour until a stiff dough forms.

Knead the dough 150 strokes on a floured surface.

Place the kneaded dough in a greased bowl.

Cover the bowl and let the dough rise for 1 to 1.5 hours, or until doubled in size.

Punch down the risen dough.

Let the dough double again.

Punch down the dough a second time and roll it into a tight loaf.

Grease a bread pan and place the loaf inside.

Let the loaf double in size in the pan.

Bake at 400 degrees F (200 degrees C) for 35 to 40 minutes, or until the bread is very dark golden brown and sounds hollow when thumped.