Cream the yeast with 3 tablespoons (1/4 cup) of the water.
Sift the flours and salt into a warmed bowl.
Stir in the sugar.
Make a well in the centre and pour in the yeast liquid and remaining water.
Draw the flours into the liquid and mix until the dough comes cleanly away from the sides of the bowl.
Turn onto a floured surface and knead for 8-10 minutes until the dough is smooth and no longer sticky.
Place in a bowl, cover with a damp cloth and leave in a warm place for 2-2 1/2 hours until doubled in bulk.
Turn onto a floured surface and knead for a further 10 minutes.
Divide the dough in half.
Form each piece into a smooth ball and place on a greased baking sheet.
Put into an oiled polythene (plastic) bag and leave in a warm place for 45 minutes or until doubled in size.
Remove from the bag.
Bake in a moderately hot oven, 375°F, Gas Mark 5 for 45 minutes until golden brown.
Turn onto a wire rack to cool.