Potato Sourdough Bread

This is an old fashioned hearty bread.  It uses a sourdough starter so it takes some time to make.  The flavour is wonderful and it goes well as an accompaniment to soup or stew or on its own in the toaster.  From Food & Drink Winter 2012

48 HOUR STARTER
(enough for 2 large loaves)
1 medium baking potato such as Idaho, about 175g
1 1/2 cups cold water, divided
1 1/2 tsp instant or traditional yeast
1 cup all purpose flour

SINGLE LARGE LOAF
1 tbsp yeast
1 tbsp sugar
1 1/2 cups water, just warm to the touch
1/2 48 hour starter mixture, about 1 cup
2 tsp salt
3 1/2 to 4 1/2 cups all purpose flour.

1. To make starter, peel and dice potato; add to small pot with 1 cup cold water.  Bring to a boil, cover and simmer over low heat for 20 minutes or until potatoes are very soft.  Pour in 1/2 cup cold tap water.  Whirl in a blender or food processor until a thick liquid; cool to lukewarm.
2. Turn potato liquid into a large steel or glass bowl; stir in 1 1/2 tsp yeast ( no need to proof this starter yeast) and flour.  Cover bowl loosely with plastic wrap and a tea towel.  Let stand at room temperature for 48 hours.  Stir occasionally; starter is ready when it smells slightly sour and looks curdled.  Starter amount is enough to make 2 large loaves.  When ready, cover starter with plastic wrap and store in the refrigerator for up to 3 days, stirring occasionally, or divide into 2 portions, 1 to use now and another for the freezer.
3. To make loaf, proof 1 tbsp yeast by stirring sugar into water and sprinkling yeast overtop, then setting aside for 5 minutes.  Then stir to dissolve yeast completely.
4. Meanwhile stir about 1 cup starter (half of the original mixture) with salt in a large mixing bowl or the bowl of a stand mixer with dough hook attached.  Stir in 1 cup of flour; then proofed yeast mixture.  Continue adding flour until dough is becoming hard to stir.  Then turn out onto a well floured work surface.  Or continue using stand mixer to knead dough.
5. Begin to knead dough, adding flour slowly as needed to have soft yet well formed dough, from 5 to 10 minutes.  All flour may not be needed.  Turn into a large, generously oiled bowl; turn dough ball in bowl so all is coated with oil.  Loosely cover with a piece of plastic wrap; let rise for 50 to 60 minutes or until doubled.  (If making to bake later, cover well and chill for up to a day.  While in the refrigerator, dough rises slowly; punch down occasionally.)
6. Preheat oven to 375 F
7. Turn dough out onto lightly floured work surface.  Lift outer edges into middle while pressing down to burst large bubbles.  Shape into a round ball.  Place smooth side up on parchment lined baking sheet.  Evenly press down until about 2 inches thick.  Or for 2 medium loaves divide dough in half and shape to fit 2 greased 9 x 5 inch loaf pans.
8. Generously coat top with flour; loosely cover with plastic wrap.  Let rise for 30 to 40 minutes or until dough has doubled.  (Refrigerated dough takes approximately 1 1/2 hours to rise.)
9. Remove plastic wrap.  Using a serrated knife gently placed on top of loaf, draw knife at an angle along top to shallowly slice a pattern of 3 or 4 slashes.
10. Bake round or loaf pans in centre of preheated oven for 30 to 35 minutes or until quite golden and smell of baking bread is very evident (love this smell). A tap on loaf bottom sounds hollow.  Cool on a rack without pan.  Bread is best on the day it is made.