Sourdough Rye Bread with Caraway

Combine yeast, 1/4 c water and sugar and let stand until very foamy Dissolve the salt in 1 C water and stir mixture into starter. Beast in the yeast mixture, then the caraway seeds. Beat in the rye flour, about 1/2 C at a time, then beat in gluten flour. Spread 2 C of the white flour in a ring on a kneading surface and pour the dough into center of ring. Mix roughly with dough scraper or spatula, then knead just until thoroughly mixed, adding as much of the remaining white flour as needed to make a medium-stiff dough. Scrape kneading surface, dust it with flour, and knead the dough very thoroughly until it is elastic and smooth. Form dough into ball, place in ungreased bowl, cover and let rise until doubled in bulk, about an hour. Punch dough down, form into two balls, cover with towel and let rest 20 minutes. Sprinkle large baking sheet with cornmeal. Form dough into balls or oblong loaves, as desired. Place on baking sheet and let rise until 3/4 proofed. Preheat oven to 425 degrees and place large pan containing 2 inches of hot water on bottom shelf. Brush loaves with glaze made of 1 tsp cornstarch cooked in 2/3 C water until translucent (about 2-3 minutes), then cooled. Slash cuts into loaves if desired. Bake 15 minutes in center of oven; lower heat to 350, remove pan of water, and bake for 30 minutes longer. Then remove loaves from baking sheet and place directly on oven shelves for 10 to 15 minutes, until there is a hollow sound when you rap on the bottom. Loaves freeze very well. Improves in flavor for at least 24 hours after baking.