The fermentation period for bread made with dry yeast may be shortened if the following yeast ferment is first prepared: Crumble yeast and soften in half cup water. Wash, pare, and boil potato in 3.5 cups water. Drain potato. Save potato water. Mash potato and add sugar and salt. Cool to lukewarm. Add yeast, and potato water. If necessary add water to make 1 litre of the mixture. Cover unused portion may be stored in the refrigerator and kept for several days.