In large bowl, combine 1 1/2 c flour, and next five ingredients (wheat germ, sugar, salt, ginger and yeast); blend well. Add water, sour cream and vinegar to flour mixture. Blend at low speed until moistened; beat 3 minutes at medium speed. Stir in an additional 2 to 2 1/2 c flour until dough pulls cleanly away from sides of bowl.
On floured surface, knead in remaining 1/2 to 1 c flour until dough is smooth and elastic, about 5 minutes. Place dough in greased bowl; cover loosely with plastic wrap and cloth towel. Let rise in warm place until light and doubled in size, 25-35 minutes.
Grease large cookie sheet. Punch down dough several times to remove all air bubbles. Allow to rest on counter covered with inverted bowl for 15 minutes. Divide dough in half; roll each half to 14x8" rectangle. Starting with longest side, roll up; pinch edges firmly to seal. Place seam side down on greased cookie sheet; taper ends to a point. With sharp knife, make five 1/4" deep diagonal slashes on top of each loaf. Cover; let rise in warm place until light and doubled in size, about 15 minutes.
Heat oven to 375F. Bake 25 minutes. In small bowl, beat egg white and water. Remove bread from oven; brush with egg white mixture. Sprinkle with poppy seed. Return to oven. Bake an additional 5 to 10 minutes or until loaves sound hollow when lightly tapped. Immediately remove from cookie sheet; cool on wire racks. Makes 2 (17 oz. ) loaves.
A Pillsbury Bake-off winning recipe, by Judy Lausch.