four days ahead of bread making, prepare the starter: combine 1 cup rye flour with 1 cup liquid, cover loosely and set in a warm place. Stir once or twice each day, adding more liquid if the mixture becomes too dry. it should bubble and give off a strong odor. when ready to prepare the dough, put the starter in a large mixing bowl, add 2 more cups of whatever liquid was used and stir. Dissolve the yeast and salt in quarter cup warm water and stir in. Then beat in the remaining rye flour and up to 4 cups of the white flour one cup at a time to make a somewhat soft biscuit like dough firm enough to hold it's shape. It should not be too sticky. turn out on a lightly floured board and knead until smooth and velvety, about 1012 minutes. Divide the dough into two equal parts and shape into balls. Place in two buttered bowls, turning to coat the dough with the butter. Cover and let rise in a warm place until doubled in bulk, about 1.5 hours. Place on a buttered baking sheet, cover and let rise again until doubled in bulk, about 40 minutes. Bake in a preheated 400o oven about 45 minutes or until the loaves sound hollow when tapped with the knuckles. Ten minutes before the loaves are done, brush the tops with the egg wash. cool, covered with towels to prevent the crust from hardening. James Beard: Beard on Bread 1973 ISBN 0-345-29550-1