My New Favourite Sourdough Rye

I thought I had perfected my sourdough rye long ago, but this loaf made me reconsider. The addition of potato water (water left from boiling potatoes) and molasses made for one of the nicest rye breads I've ever baked. This bread will require two days to make, but you'll be rewarded with one hell of a bread.

You will need:

For the sponge:
2 cups fed sourdough starter (mine is white, but rye would be super if you have it)
2 cups water (room temp is fine)
(about) 3 cups strong flour or enough to make a firm sponge that is no longer runny

Mix all and cover with cling film. Let stand 8-12 hours.

To half the sponge add (save the rest for another bread)

1 cup room temperature potato water
1 tablespoon coarse salt
1-2 tablespoons caraway seeds
2 tablespoons full flavor molasses or dark treacle
8 teaspoons vital wheat gluten
4-5 cups medium rye flour

Mix well, and let stand 30 minutes, covered.

Over the next two hours, give a series of two folds every thirty minutes. Cover, and set in the fridge overnight.

next day:

Remove dough from fridge and shape. Place on a baking sheet covered with cornmeal. Cover with a damp tea towel, and let rise several hours until doubled (this took two and a half hours in my cool-ish kitchen. Meanwhile, make a cornstarch glaze of 4 tablespoons cornstarch dissolved in a few tablespoons of water and heated until thickened. Cover with foil, and set aside.

Meanwhile, about 40 minutes before baking time, preheat the oven to 475 degrees F. Heat a pan in the bottom of the oven as it heats. Before the bread is slashed and loaded, toss a handful of ice cubes into the pan to create steam. Slash loaf, and place in oven. Immediately reduce heat to 425 degrees F. Bake 25 minutes. Remove pan from bottom of oven, rotate the pan with the bread, and bake another 25-30 minutes or until browned and hollow sounding or if using an instant read thermometer the bread reaches an internal temperature of 205 degrees F.

Remove bread to a rack, and immediately brush a thin layer of glaze on loaf. Let cool completely before slicing. This bread will benefit from a 24 hour rest before eating-but it is doubtful you can wait that long.

Bonus Bread:
I made a combination rye/wheat sourdough also making use of potato water.